- Open navigation
Herschel and the Puzzle of Infrared
By jack r. white.
An astronomer took a mental leap to first connect light and heat.
This Article From Issue
May-june 2012, volume 100, number 3.
Most encyclopedias and physics books credit the great British astronomer Sir William Herschel with the discovery of infrared radiation in 1800. It’s a good story, but it is not strictly correct—it trivializes the true significance of what Herschel found.
We all discover infrared at a young age when we feel warmth at a distance from a hot object, and we know that these rays are invisible—warmth can be felt in total darkness. What Herschel discovered was subtler than the existence of invisible radiation. He found the first solid evidence that light and infrared are the same quantity that we know today to be electromagnetic radiation. Through a series of simple experiments, Herschel found the first piece in one of the great puzzles of physics that took another century to solve.
Figure 1. An image of infrared radiation from a hot mug is colored with red, orange and yellow shades to show heat, but hot objects on their own often do not show any visible signs of their emissions. Although it is now common knowledge that both infrared and visible light are part of the electromagnetic spectrum, connecting the two seemingly disparate energy sources took some intricate experiments—and unfettered curiosity—by the famous 18th-century British astronomer Sir William Herschel.
Photograph courtesy of the author.
The best information about Herschel’s experiments is found in his original papers. His recorded data and many of his comments appear to have been taken directly from his lab notes, and their freshness and authenticity come through even today. The biggest challenge reading his work is to follow his line of reasoning through many digressions and pages of raw temperature data.
In a paper read before the Royal Society on March 27, 1800, Herschel called this warmth felt at a distance “radiant heat.” This description is still a good working term for infrared radiation. The term “infrared” did not enter scientific vocabulary until the 1880s. Infra is Latin for “below,” but researchers have been unable to trace the source of who initially coined the name.
Figure 2. A 1785 portrait of Sir William Herschel by Lemuel Francis Abbott shows the astronomer in his late 40s.
National Portrait Gallery, London
Herschel was not originally a scientist. He rose from obscurity as a German immigrant in a military band to become an accomplished musician and composer. In 1773, at age 34, six years after moving to Bath to take a position teaching music and playing in concerts, he did something that changed his life and fortunes. He bought a small telescope and a book on astronomy.
By the following year, he was grinding his own mirrors to build larger and better quality telescopes, and spending his nights studying the heavens. Herschel’s craftsmanship rapidly took his hobby to public recognition as the foremost telescope manufacturer of his time. His fame peaked after he discovered the planet Uranus in 1781, which led to his appointment as the king’s astronomer.
Following his appointment, which came with an annual salary of £200, Herschel was able to devote all his time to astronomy. He and his sister, Caroline, settled in the town of Slough, near Windsor Castle. A condition of his appointment was that he be available to King George III and the royal family any time they wished to view the stars.
Herschel’s foray from astronomy to infrared was a fortuitous tangent from his effort to find the best color for a filter that would allow him to safely view the Sun. His speculations and conclusions were often contradictory: Many were wrong, but some were extraordinarily prescient. The story of Herschel’s experiments is that of the role of human perception in scientific discovery, as well as the conflict between conventional beliefs and concepts never before encountered.
Joining Heat and Light
The vast electromagnetic spectrum stretches from gamma rays (whose wavelengths can be smaller than the width of an atom) to radio waves (whose wavelengths can reach thousands of kilometers). Of this range, humans are only able to directly sense radiation in two small bands. Our eyes see light, which occupies a narrow sliver of wavelengths from 0.4 to 0.7 micrometers, centered approximately where the Sun’s radiant power is at its maximum. Our skin feels warmth mainly from infrared, which spans the range of wavelengths between light and microwaves, up to about 1,000 micrometers.
Figure 3. The electromagnetic spectrum stretches from gamma rays to radio waves, but human beings can directly sense only two small segments. Our eyes see light, a narrow band of wavelengths centered approximately where the Sun’s radiant power is at its maximum. Our skin feels warmth across the spectrum, but mainly from infrared, which spans the range of wavelengths between light and microwaves. Everyday experience alone would not lead us to believe they are the same quantity.
The boundary between light and infrared is determined by the long-wavelength limit of the human eye’s response. Everyday experience would not lead us to believe light and infrared are the same kind of energy. Indeed, two compelling pieces of evidence suggest, logically, that they are not related.
First, we experience light and infrared differently with different senses. We see light, perceiving different wavelengths as different colors, but we feel infrared only as warmth. Second, light and infrared aren’t always found together. Most sources of light also emit infrared, but infrared is often found by itself. A familiar example is an electric grill not hot enough to glow: If the room is completely dark, we can still feel the warmth from the grill, but we can’t see it.
Figure 4. Herschel’s mental leap to connect light and radiant heat had to overcome everyday experience with each energy: If light and heat are the same, we’d expect to find them together, and sometimes radiant heat can be found alone (as with hot coffee or the human body, at middle and bottom insets ). A century after Herschel, quantum theory explained that radiant power had a wave-shaped distribution whose position on the spectrum shifts upward and toward shorter wavelengths with increasing temperature ( blue arrow ). Around 700 degrees Celsius, the shortwavelength edge of the curve pushes sufficiently into the visible range for the human eye to see a red glow, such as from an electric grill ( top inset ). Infrared images were taken in the band of wavelengths indicated by the gray box.
Photographs courtesy of the author.
These differences may be why the connection was not made for so many centuries in spite of much experimentation. Perhaps this counterintuitive association is why the connection was found almost by accident by a person with no formal scientific training.
Herschel had observed features on the Sun’s surface for a number of years, presenting a paper on the Sun and fixed stars to the Royal Society in 1794. Being able to observe sunspots with a large telescope without damaging his eyes had long been a challenge. Through experiments with different combinations of colored and darkened glass, Herschel observed, as he noted in this paper:
What appeared remarkable was, that when I used some of them, I felt a sensation of heat, though I had but little light; while others gave me much light, with scarce any sensation of heat.
This observation led to the thought that different colors might, in Herschel’s words, “have the power of heating bodies very unequally distributed among them.” Herschel further reasoned that if the heating power were unequally distributed, the illuminating power might be as well. There might be a single best color for seeing, and it might be different than the one for maximum heating. Knowing these qualities would help him find the best filter to view the Sun.
Drawing on his experience making telescopes, Herschel built an instrument to test his hypothesis. He made what we would call a spectrometer, or more precisely, a spectroradiometer: an instrument to measure the magnitude of radiant power at different wavelengths.
His first instrument consisted of three components: a prism set in a south- facing window to catch the sunlight and direct and disperse the colors down onto a table; a small panel of cardboard with a slit wide enough for only a single color to pass through; and three mercury- in-glass thermometers (of which he used two) with their bulbs blackened to better absorb light. Thermometers were not common household items in 1800, but Herschel had one of his own and borrowed two more from a colleague.
Figure 5. Herschel directed the dispersed colors from a prism onto a piece of cardboard with a slit that allowed only a single color to pass. To measure relative heating, he kept one thermometer in the light and the other in shadow.
He placed one thermometer in the light and kept the other two in darkness to measure the room’s ambient temperature. Herschel understood there were, as he expressed it, “causes acting in different ways” (in other words, conduction and convection) that affected the stabilization temperature of the thermometers, and he wanted to quantify the heating caused by the light alone.
Spectrometers today have much higher resolution, greater sensitivity and faster response, but the basic functional elements are the same as Herschel’s. Prisms are still used, but better resolution is usually obtained through wave interference —wavelengths are separated by constructive and destructive interference, where their waves either add together or cancel out. The detector today would be a cryogenically cooled semiconductor—much smaller, faster and more sensitive than a mercury thermometer. But Herschel’s instrument, in the hands of the careful experimenter that he was, gave surprisingly accurate measurements.
With his device set up on a sunny day, Herschel methodically took temperature measurements, first comparing the thermometers’ readings at ambient conditions to ensure baseline agreement. It was cold in the room. His starting temperatures averaged 43.5 degrees Fahrenheit. After some experimentation, he settled on using his own thermometer with its half-inch-diameter bulb exposed to the light and used the larger of the borrowed ones as the ambient reference.
Herschel positioned the measuring thermometer in the band of colored light for each reading. At each color position, he allowed the thermometer to stabilize for 10 minutes before taking a reading. He took a series of measurements, starting with red, which gave an average reading of 67/8 degrees above ambient. Green gave 31/4, and violet light gave a 2-degree average increase.
From these data, Herschel felt that he had proven his hypothesis about heating being unequally distributed and could move on to the illumination experiment. As he stated in his initial conclusion:
Which only goes to prove, that the heating power of the prismatic colours, is very far from being equally divided, and that the red rays are chiefly eminent in that respect.
To find the maximum of illumination, he directed colors onto a variety of small objects that he viewed through a 27-power microscope. From the brightness and clarity of what he saw, he judged the relative illumination.
The illumination experiment also went well. He did 10 separate experiments with objects viewed in different colors. He attempted to distinguish between the color having the maximum of illumination and that having the sharpest resolution or “distinctness.” He was unable to reach a conclusion about resolution, but for illumination, he was able to state:
The maximum of illumination lies in the brightest yellow, or palest green. The green itself is nearly equally bright with yellow; but, from the full deep green, the illuminating power decreases very sensibly.
This observation is remarkable: Yellow-green is near the wavelength where the Sun’s radiant power is a maximum and is exactly where the eye’s sensitivity is greatest.
A Fortuitous Tangent
Feeling he had proven that both radiant heat and light are not equally distributed across the colors, and with measurement results showing their differences, Herschel should have been ready to move on to applying these results to his problem of viewing the Sun. But he didn’t do so immediately. Instead, he returned to the temperature data.
Something about the temperature readings clearly bothered him. He had expected, as he found, that the readings would be different for the various colors. But the measurements also showed something he did not expect: a trend, rather than a peak.
Figure 6. With his first temperature readings, Herschel believed he had proven the heating power of light was not equally distributed across the visible spectrum, as he had found the greatest heating from red. But his readings also showed a trend that appeared to point toward a maximum somewhere in the dark region beyond red. It was a trend that he felt compelled to follow.
The heating was greatest in red, but the curve did not appear to reach a maximum in the visible spectrum. Instead, the readings seemed to point somewhere in the dark region beyond red. He felt compelled to follow this trend.
If the maximum lay outside the visible spectrum, then the heating was not from light but from something else. Herschel used the expression “invisible light,” cautiously phrasing it in a way that indicated he knew it to be an oxymoron. (If rays are invisible, then they aren’t light.) As he expressed it:
I likewise conclude that the full red falls still short of the maximum of heat; which perhaps lies even a little beyond visible refraction. In this case, radiant heat will at least partly, if not chiefly, consist, if I may be permitted the expression, of invisible light; that is to say, of rays coming from the sun, that have such a momentum as to be unfit for vision.
By describing the rays in terms of momentum, Herschel was not anticipating the discoveries of quantum physics, still a century in the future. Photons at infrared wavelengths do have less energy than those in the visible band. As a result, they do “have such a momentum as to be unfit for vision.” He was not looking a century ahead but a century back—to Isaac Newton’s experiments with light in the late 1600s.
Herschel accepted without question Newton’s beliefs on the “corpuscular” nature of light. A strong case for light being a wave had been made by Newton’s contemporary, Christiaan Huygens, but the theory of light as streams of minute particles dominated science at the time, especially in Britain. This viewpoint changed within the next 15 years, but at that moment, Herschel thought of light as particles that had more or less “efficacy” in their effect on matter.
It wasn’t the concept of invisible rays that so interested Herschel. What captivated him were the properties of these rays. It was clear to him that radiant heat had the same optical properties of “refrangibility” (“refraction” in modern usage) and dispersion as light.
Refraction is the change in direction of a ray as it enters or exits a transparent medium that causes a change in velocity, such as between air and glass. Dispersion is the effect of refraction on multiple wavelengths, causing different rays to refract at differing angles. We see the effects of the dispersion of light most commonly from rainbows and prisms. Herschel didn’t think of light in terms of wavelength, but as a lens-maker, he was very familiar with the effects of dispersion and how to correct for it to produce lenses that minimize what is known today as chromatic aberration , where different colors converge to a focus at varying distances from the lens. As he wrote:
I must now remark, that my foregoing experiments ascertain beyond a doubt, that radiant heat, as well as light, whether they be the same or different agents, is not only refrangible, but is also subject to the laws of dispersion arising from its different refrangibility.
The telescope designer in Herschel grasped the significance immediately: If light and radiant heat have the same optical properties, if they exhibit the same behavior in their interactions with matter, might that indicate they are the same quantity? He notes: “
May not this lead us to surmise, that radiant heat consists of particles of light of a certain range of momenta, and which range of momenta may extend a little farther, on either side of refrangibility, than of light?
It was a question that dominated Herschel’s thoughts and effort for much of the rest of the year. He must have worked rapidly, because just 9 days after writing his first paper and 10 days before he formally presented it, he wrote a second, shorter paper to the Royal Society titled “Experiments on the Refrangibility of the Invisible Rays of the Sun.”
The title of this paper has an intriguing echo of Newton. In Newton’s Opticks (1730), his Proposition II, Theorem II is titled “The Light of the Sun consists of Rays differently Refrangible.”
Newton clearly had great influence on Herschel. The latter’s approach was nearly identical to Newton’s experiments using a prism placed in a window to project colors onto a wall. Herschel took Newton’s basic qualitative method of viewing the spectrum and turned it into a quantitative instrument. He may have felt—justifiably—that he was continuing the work Newton had begun with the colors of light by extending the concept of “different refrangibility” to the rays of the Sun that lay beyond the visible colors.
Figure 7. Herschel had to modify his instrument to follow the heating trend into the invisible, as this drawing from his second paper shows. Lacking the concept of wavelength, his only reference was in relation to where the last visible light fell. He marked off five parallel lines and positioned the board so the edge of red fell at the first line. His temperature readings increased to a maximum at approximately half an inch beyond red and diminished beyond. The experiment demonstrated that radiant heat has the same optical properties as light.
Herschel began his second experiment by slightly modifying his spectrometer to take temperature readings into the dark area on his board, beyond red. His only reference was in relation to where the colors fell on the table. He marked off five parallel lines spaced half an inch apart on a sheet of white paper, with the first line at the edge of the band of red light. Thus anchored to the edge of the visible, Herschel ventured into the darkness beyond.
He took readings with his thermometer, following the upward trend to a maximum and beyond, until the heating began to diminish. The tone of Herschel’s second paper is one of excitement and confidence in his findings. Throughout his experiments, he ventures few opinions that are not firmly supported by data, but he concludes this paper with an argument based on philosophy:
To conclude, if we call light, those rays which illuminate objects, and radiant heat, those which heat bodies, it may be inquired, whether light be essentially different from radiant heat? In answer to which I would suggest, that we are not allowed, by the rules of philosophizing, to admit two different causes to explain certain effects, if they may be accounted for by one.
Herschel’s reputation as an astronomer probably helped ensure that his papers were favorably received by most scientists, but not by all. His third paper opens on a decidedly defensive note. He appears to have been attacked by a person he refers to as a “celebrated author,” who took offense at the phrase “radiant heat.” This detractor may have been John Leslie, who was considered an authority on heat and clearly resented the intrusion of an amateur into his domain. In a letter published in A Journal of Natural Philosophy, Chemistry, and the Arts by William Nicholson , Leslie wrote:
It would appear this able astronomer, on entering a new line of enquiry, has neither employed apparatus suited to the nicety of the subject, nor guarded sufficiently against the numerous and latent sources of error. I consider myself entitled to speak with the greater confidence because I had long directed my researches in the same channel.… I do not hesitate, therefore, to maintain that Dr. Herschel’s capital proposition originates in fallacious observations.… And whatever my sentiments were respecting the validity of the conclusions, I resolved calmly and impartially to subject the pretended facts to the test of experiment. When a photometer was placed beyond the spectrum, … no effect whatever was perceived.
If Leslie’s differential thermometer (he called it a “photometer”) found no heating beyond the visible as he claimed, then it was badly in error. This point was later proven dramatically by independent experiments conducted by the Royal Society. To deflect criticism, Herschel switched from the term “radiant heat” to “the rays that occasion heat.”
Light was also a contentious issue. Herschel’s brash assertions about radiant heat and light had stepped on the toes of conventional belief. With light, he again adopted a cautious stance, but this time he countered with a challenge calculated to silence his critics:
I must also remark, that in using the word rays, I do not mean to oppose, much less to countenance, the opinion of those philosophers who still believe that light itself comes to us from the sun, not by rays, but by the supposed vibrations of an elastic ether, every where diffused throughout space; I only claim the same privilege for the rays that occasion heat, which they are willing to allow to those that illuminate objects.
The criticism he received did not slow his experiments, but these attacks may have had an impact. By the second part of his final paper, his emphasis changed from finding evidence supporting the similarity between light and radiant heat to that supporting their difference.
Herschel’s third paper proposed seven comparisons between light and radiant heat. The first concerns two human senses. The next five are interactions with matter that were known in 1800: reflection, refraction, “different refrangibility” (dispersion), transmission through “diaphanous bodies” (transparent media) and scattering from rough surfaces.
The paper’s final proposition asks whether radiant heat, if sufficiently strong, is able to stimulate vision. This question is critical because the complete answer explains why light and infrared are usually together but infrared can be present without light. With his 18th experiment, Herschel determined beyond doubt that increasing its power cannot make infrared visible.
Herschel embarked on an extensive instrument-building program to examine and measure each property. To the original prism and mercury thermometers he added a variety of lenses and mirrors in a dozen different configurations and an extensive array of transparent materials to compare transmission.
In more than 200 experiments, he recorded page after page of readings using every available illuminating source viewed through different combinations of mirrors, prisms and lenses. He confirmed again and again, in every way he could test, that light and radiant heat have the same optical properties.
The frantic pace of his later experiments may have caused him to miss or misinterpret connections, especially after he began to look for differences instead of similarities. He did a detailed experiment showing that the focal length of a refractive converging lens was longer for heat than for light, without realizing that the difference in focal length is caused by the same dispersion as a prism.
He measured the effects of scattering, and found, correctly, that light scatters more than infrared. Herschel attributed the difference to light and heat having different natures, rather than as evidence of similar behavior in a different interaction with matter (as scattering is dependent on wavelength).
Herschel did not have a scientist’s insight into the causes of these phenomena, and he had limited ability to formulate mathematical descriptions of his findings. His strengths were his practical knowledge of optics combined with craftsmanship in the fabrication of instruments and his powers of observation.
Figure 8. Herschel’s final paper in 1800 contained the first graph showing the spectral distributions of visible light and radiant heat (what he called the “spectrum of illumination” and the “spectrum of heat”). Its two curves are of different, almost unrelated quantities and their misleading appearance on the same graph ultimately led Herschel to wrongly conclude that rays of light and radiant heat are of a different nature after all.
His final paper, presented November 6, 1800, contained the first graph made showing the spectral distributions of visible light and infrared radiation. He called these curves the “spectrum of illumination” and the “spectrum of heat.” On the vertical axis, Herschel plotted measured temperature and perceived brightness. He set their maxima equal (a format called peak-normalization ) to compare the relative extent and shape of the distributions and the location of their maxima. For the horizontal axis, not having the concept of wavelength, he used distance in relation to where the visible colors fell. The horizontal axis is reversed from today’s convention of increasing wavelength from left to right.
Herschel’s graph was the product of imagination, insight and months of painstaking work, but it was fatally misleading. Its appearance was probably the deciding factor in his conclusion that light and radiant heat are fundamentally different after all. As he wrote (with the area “ASQA” encompassing the spectrum of heat and “GRQG” the spectrum of illumination):
A mere inspection of the two figures... will enable us now to see how very differently the prism disperses the heat-making rays, and those which occasion illumination, over the areas ASQA, and GRQG, of our two spectra! These rays neither agree in their mean refrangibility, nor in the situation of their maxima. At R, where we have most light, there is but little heat; and at S, where we have most heat, we find no light at all!
Reevaluating the Data
The presentation of data can strongly influence their interpretation. Even today, it is difficult to look at Herschel’s graph without the impression that light and radiant heat are two different types of rays. Herschel’s curves are both accurate, but they are of different, almost unrelated quantities and should not be graphed together. His error was not in his basic data but in his assumption that the curves were comparable.
To evaluate Herschel’s spectra, we need to see how the Sun appeared from the village of Slough at the time of his measurements. Herschel did not record the date and time, but analysis of the curve shape indicates the data likely came from his first experiments, and thus were probably taken sometime in late February or early March. Slough lies at latitude 51.5 degrees north, which would make the solar zenith around 61 degrees (29 degrees above the horizon) at local noon.
If Herschel’s measurements had been made in summer, when the Sun is higher in the sky, the maximum he found would have been closer to the center of the visible spectrum. But in winter, with a longer atmospheric path, the maximum of the spectral irradiance (the incident power density as a function of wavelength) is pushed toward red due to atmospheric scattering of the shorter wavelengths.
A computer atmospheric model was used to calculate the distribution of solar irradiance that illuminated Herschel’s prism, and the curve was normalized for comparison. Herschel was meticulous in recording his temperatures, but although he owned a number of prisms of both crown and flint glass with a variety of angles, he did not record what was used in his first experiments. The curve shown assumes his prism was of crown, which was common in 1800, and had a 60-degree angle.
Figure 9. Comparing Herschel’s “spectrum of heat” with that of sunlight shows his measurement was surprisingly accurate. His curve is displaced toward longer wavelengths due to the dispersion curve of glass. Without the concept of wavelength and a known radiation source, this effect could not have been corrected in Herschel’s time. Herschel’s curve confirms his first hypothesis that the heating power of sunlight is not equally distributed across the spectrum. And, the fact that his curve is continuous in its transition across the visible and into the infrared strongly supports his second hypothesis that light and radiant heat are the same quantity.
Comparing his spectrum of heat with the solar spectrum shows that Herschel made remarkably good measurements considering the limitations of his instrument and that he had no idea how a solar spectrum should look. His curve is displaced toward longer wavelengths because of the dispersion curve of glass.
Relating the index of refraction to wavelength, the dispersion curve causes refraction to spread the wavelengths across the target board nonuniformly. At each position, moving toward longer wavelengths, the spectral width or band of wavelengths that the thermometer receives becomes progressively wider. A wider spectral width contains more power, which increases the reading. The result gives readings at longer wavelengths that are weighted more heavily than those at shorter wavelengths.
Today, the nonuniform response of a spectrometer can be corrected. But such calibration requires knowledge of wavelength and a source of known radiant power, neither of which were concepts in Herschel’s time. The displacement of his heat curve is not erroneous in itself; it was actually serendipitous because it created the temperature trend that led him into the infrared.
In spite of its displacement, the shape of Herschel’s curve confirms his first hypothesis that the heating power of sunlight is not equally distributed across the spectrum. The fact that his curve is continuous in its transition into the infrared supports his second hypothesis that light and radiant heat are the same quantity.
For the spectrum of illumination, it must have seemed logical to Herschel to plot this on the same graph because his original objective was to find a filter that would maximize light while minimizing heat. His curve was accurate, but it did not show what he thought.
Figure 10. The output of any sensor is the product of two curves: the spectral distribution of received radiation and the spectral response of the sensor. The narrowness of the eye’s response ( black dashed line ) produces a product curve ( red line ) that is nearly the same shape as the response curve. The result is more a map of how the human eye responds than of how light is distributed. Herschel’s error was assuming that this curve should resemble his temperature measurement.
Herschel was missing a concept, unknown in 1800, but fundamental to radiometry today: the effect of sensor response. The reading obtained with any instrument or sensor, including the human eye, results from the product of two curves: the distribution of the received power and the curve of instrument response, which includes the spectral transmission of all optical elements.
If an instrument responds nonuniformly, as most do, then the response shape is impressed on the received radiation in a way that cannot be extricated without independent knowledge of how the radiation is distributed and how the instrument responds. Lacking this concept, Herschel assumed the spectra he measured accurately represented how the radiation was distributed.
Any spectrum created from what the eye sees will be zero outside the eye’s limits. Inside its limits, the power received at any wavelength will be weighted by the eye’s sensitivity to that color. The greatest sensitivity, as Herschel correctly determined, is yellow-green at a wavelength of 0.555 micrometers.
Human color vision is more complicated than shown, but the International Commission on Illumination curve for the light-adapted (or photopic ) eye illustrates the concept (see figure 10). The sensation of sight is so rich in information that we don’t often think about how narrow is the slice of the electromagnetic spectrum that we see. Because of its narrowness, the shape of the response curve and that of its product with the solar spectrum are nearly identical.
As a result, Herschel’s spectrum of illumination is more a map of how the human eye responds to colors than how light is actually distributed. He saw the shape of his curve as evidence that light is not equally distributed across the spectrum. His hypothesis was correct, but his data did not show it. He would have gotten an almost identical curve even if the distribution were uniform.
By November 1800, Herschel was approaching the end of what was possible to achieve given the knowledge and technology of his time. He was also almost certainly feeling pressure to return to astronomy.
In the end, the misleading appearance of his graph and the different sensations of seeing light and feeling heat won out over all of his carefully collected evidence, leading him to conclude that the two energies are not the same after all. Actually, he never reached a firm conclusion. The closest Herschel came was to again invoke philosophy, this time to argue against his original thought:
It does not appear that nature is in the habit of using one and the same mechanism with any two of our senses.… Are we then here, on the contrary, to suppose that the same mechanism should be the cause of such different sensations, as the delicate perceptions of vision, and the very grossest of all affections, which are common to the coarsest parts of our bodies, when exposed to heat?
This argument would not be credible today and probably sounded weak even in 1800, but it was a way of bringing his quest to a close. Herschel was surely disappointed, but he had achieved more than he or any contemporary realized.
He discovered that radiant heat has the same optical properties as light. He confirmed his hypothesis that heating power is not equally distributed across the spectrum. He performed the first radiometric measurement of spectral radiant power across the visible into the infrared and found it to be a smooth, continuous curve.
Our present understanding of electromagnetic radiation grew from Herschel’s simple measurements of temperature in sunlight to the unification of the spectrum mathematically by James Clerk Maxwell in 1861 and, ultimately, to Max Planck’s formulation of the quantum theory in 1900. Herschel could not conclusively prove that light and radiant heat are the same quantity, but his experiments provided very strong evidence and were the first piece of the puzzle that others later built on.
- Barr, E. S. 1960. Historical survey of the early development of the infrared spectral region. American Journal of Physics 28:42.
- Chester, T. 1999. Reconciling the Herschel Experiment. http://tchester.org/znet/calculations/herschel/index.html
- Englefield, H. 1802. Experiments on the Separation of Light and Heat by Refraction. In a Letter from Sir H. C. Englefield, Bart. F.R.S. to Thomas Young, M.D. F.R.S. Journal of Natural Philosophy, Chemistry, and the Arts: by William Nicholson. London: G. G. and J. Robinson. Vol. III pp. 125–130. http://books.google.com/books?id=6iTPAAAAMAAJ
- Herschel, W. 1800. Investigation of the Powers of the Prismatic Colours to Heat and Illuminate Objects; With Remarks, That Prove the Different Refrangibility of Radiant Heat. To Which is Added, an Inquiry into the Method of Viewing the Sun Advantageously, with Telescopes of Large Apertures and High Magnifying Powers. Philosophical Transactions of the Royal Society 90:255–283.
- Herschel, W. 1800. Experiments on the Refrangibility of the Invisible Rays of the Sun. Philosophical Transactions of the Royal Society 90:284–292.
- Herschel, W. 1800. Experiments on the Solar, and on the Terrestrial Rays that Occasion Heat; With a Comparative View of the Laws Which Occasion Them, Are Subject, in Order to Determine Whether They Are the Same, or Different. Part I and Part II. Philosophical Transactions of the Royal Society 90: 293–326 and 437–538.
- Herschel, W., and J. L. E. Dreyer. 1912. The Scientific Papers of Sir William Herschel, Volume I. London: The Royal Society and The Royal Astronomical Society, and Dulau & Co., Ltd.
- Holden, E. S. 1881. Sir William Herschel, His Life and Works . London: W. H. Allen. http://books.google.com/books?id=GIwBAAAAQAAJ
- Leslie, J. 1801. Observations and Experiments on Light and Heat, with some Remarks on the Enquiries of Dr. Herschel, Respecting those Objects. Journal of Natural Philosophy, Chemistry, and the Arts: by William Nicholson. London: G. G. and J. Robinson. Vol. IV pp. 345. http://books.google.com/books?id=tItEAAAAcAAJ
- Lovell, D. J. 1968. Herschel’s dilemma in the interpretation of thermal radiation. Isis 59:196.
- Newton, I. 1730. Opticks: Or a Treatise of the Reflections, Refractions, Inflections and Colours of Light . London: William Innys. http://books.google.com/books?id=GnAFAAAAQAAJ
- Young, T. 1802. The Bakerian Lecture: On the theory of light and colours. Philosophical Transactions of the Royal Society 92:12–48.
American Scientist Comments and Discussion
To discuss our articles or comment on them, please share them and tag American Scientist on social media platforms. Here are links to our profiles on Twitter , Facebook , and LinkedIn .
If we re-share your post, we will moderate comments/discussion following our comments policy .
Read More in This Issue
Plenty of room at the bottom.
- More in Physics
AMSCI ICON NAVIGATION:
- Navigation Menu
- Log In, Register
- Select Options (not present on all pages)
Click "American Scientist" to access home page
- View all journals
- Explore content
- About the journal
- Publish with us
- Sign up for alerts
- BOOKS AND ARTS
- 26 June 2019
The infrared Universe
- Michael Rowan-Robinson 0
Michael Rowan-Robinson is emeritus professor of astrophysics at Imperial College London and author of Night Vision: Exploring the Infrared Universe .
You can also search for this author in PubMed Google Scholar
You have full access to this article via your institution.
The Eagle nebula imaged by the Spitzer Space Telescope. Credit: NASA/JPL-Caltech/Institut dAstrophysique Spatiale
More Things in the Heavens: How Infrared Astronomy Is Expanding Our View of the Universe Michael Werner and Peter Eisenhardt Princeton University Press (2019)
Infrared astronomy has revealed a dynamic cosmos. By harnessing infrared radiation — electromagnetic radiation with wavelengths longer than those of visible light — astronomers can study interstellar gas and the dust grains spread through it, the birth and death of stars, the formation of planets and the monster bursts of star formation when galaxies collide. After William Herschel used a thermometer to discover radiation beyond the red end of the visible spectrum in 1800, the field developed slowly. By the mid-to-late twentieth century, it had come into its own, evolving from ground-based observations to airborne and finally space telescopes.
In More Things in the Heavens , Michael Werner and Peter Eisenhardt focus on the Spitzer Space Telescope, the NASA mission, launched in 2003, on which they have both worked for decades. They unashamedly fly the flag for its achievements, from imaging dwarf planets in the outer Solar System to detecting the Universe’s most distant galaxies.
Spitzer, named after US astrophysicist Lyman Spitzer (1914–97), is an 85-centimetre telescope capable of cooling passively in space to 26 °C above absolute zero (26 kelvin); a helium cryostat further cools its three instruments to 1.2 kelvin. These instruments are the Infrared Array Camera, the Multiband Imaging Photometer and the Infrared Spectrograph. Launched in an unusual orbit of the Sun, trailing behind Earth, Spitzer is now two-thirds of the way to the opposite side of our planet’s orbit.
Spitzer is only one of six infrared telescopes that debuted between 1983 and 2009. (I was lucky enough to have been involved with five of them, either as a member of the science team for the mission or one of the instruments, or as leader or co-leader of major survey programmes.) The first was the Infrared Astronomical Satellite (IRAS), launched in 1983 as a joint project of the United States, the Netherlands and the United Kingdom. That was followed by the European Space Agency (ESA) Infrared Space Observatory (1995), Japan’s Akari (2006), ESA’s Herschel Space Observatory (2009) and NASA’s Wide-field Infrared Survey Explorer (WISE, 2009).
In some ways, Spitzer has been the most remarkable. As Werner and Eisenhardt note, it took 32 years to reach the launchpad. Originally proposed in 1971 as a mission based on the Space Shuttle, five years before the pioneering free-flying survey mission IRAS was conceived, Spitzer entered a saga of funding squeezes, cancellations and de-scoping. Yet the science team, including the authors, doggedly persisted, and brought the project to fruition. Perhaps because Spitzer’s Byzantine path through the NASA system was vividly described by George Rieke in his 2006 book The Last of the Great Observatories , Werner and Eisenhardt relegate it to the appendix. Yet, by doing so, they miss an opportunity to share some of the pain and triumph.
Technicians put final touches on NASA’s Spitzer Space Telescope before its launch. Credit: NASA/JPL
The second unusual feature of Spitzer was that in 2009 — on completion of its nominal mission and when its coolant was exhausted — it entered an ‘extended mission’. Although most of its instruments could no longer function, the two shortest-wavelength cameras on the Infrared Array Camera continued to operate at the spacecraft temperature of 26 kelvin. They are still going.
What has been achieved over that extra decade, related in More Things in the Heavens , was a complete revelation to me. Most notable is what Spitzer has revealed about exoplanets, outer Solar System objects and the disks of dust and debris that orbit stars, analogous to the Solar System’s Kuiper belt. IRAS first detected disks around other stars in 1983, but Spitzer has enormously expanded our understanding of their connection to planet formation. More than 140 Kuiper belt objects similar to Pluto have been found, and 45 imaged by Spitzer.
On the road with Star Men
The sections dealing with these subjects, and with the outer Solar System and comets, are the most original; much of the material is relatively new. High points from 2014 to 2017 alone include the imaging and mass determination of a near-Earth asteroid, and detection of an exoplanet by measuring how its gravity affects light from a background star. Werner and Eisenhardt also discuss insights from infrared observations of the Milky Way, the close neighbouring galaxies called the Magellanic Clouds, and others. After a ponderous chapter on infrared galaxy counts come quasars and active galactic nuclei, galactic clusters, the history of star-formation and, finally, Spitzer’s role in estimating the redshifts of the most distant galaxies, a remarkable achievement for a telescope of its size.
Werner and Eisenhardt mention, too, how NASA devoted a large proportion of Spitzer’s first-year observation time to six ‘large programmes intended to leave a lasting scientific legacy. These covered a wide range of scientific goals. GLIMPSE, for instance, was a survey of the Milky Way, whereas SWIRE, COSMOS and GOODS explored the extragalactic Universe to various depths. This — in my view — enlightened approach continued throughout the mission: in the end, more than 30 legacy programmes were approved. However, there is little systematic account of them here.
The book’s title refers to Hamlet’s declaration in William Shakespeare’s eponymous play: “There are more things in heaven and earth, Horatio,/Than are dreamt of in your philosophy.” There are also more things in the story of infrared astronomy than appear here. The contributions of other missions and ground-based efforts tend to be mentioned only in passing. I might have preferred to see a bit more on the theoretical work that makes sense of the Spitzer observations. And the general reader might find the many scientific diagrams perplexing.
Spitzer, however, merits a detailed and authoritative account of its successes, and More Things in the Heavens is just that. Eisenhardt was also a member of the science team for the WISE mission, launched in December 2009. Werner, by contrast, has devoted his entire scientific career to Spitzer, and deserves to bask in the glow of its success.
Nature 570 , 443-444 (2019)
- Astronomy and astrophysics
- Astronomical instrumentation
Europe’s backlog of space missions worsened by rocket woes
News 03 MAR 23
Are telescopes on the Moon doomed before they’ve even been built?
A shared accretion instability for black holes and neutron stars
Article 01 MAR 23
SpaceX satellites and others are marring Hubble’s vision
Research Highlight 03 MAR 23
Ancient genomes show how humans escaped Europe’s deep freeze
News 01 MAR 23
100 years of dinosaur eggs
Correspondence 28 FEB 23
From the archive: Leo Szilard’s science scene, and rules for maths
News & Views 28 FEB 23
Research Scientist - Chemistry Research & Innovation
MRC National Institute for Medical Research
Harwell Campus, Oxfordshire, United Kingdom
POST-DOC POSITIONS IN THE FIELD OF “Automated Miniaturized Chemistry” supervised by Prof. Alexander Dömling
Palacky University (PU)
Olomouc, Czech Republic
Ph.D. POSITIONS IN THE FIELD OF “Automated miniaturized chemistry” supervised by Prof. Alexander Dömling
Czech advanced technology and research institute opens a senior researcher position in the field of “automated miniaturized chemistry” supervised by prof. alexander dömling.
Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.
- Explore articles by subject
- Guide to authors
- Editorial policies
- Entertainment & Pop Culture
- Geography & Travel
- Health & Medicine
- Lifestyles & Social Issues
- Philosophy & Religion
- Politics, Law & Government
- Sports & Recreation
- Visual Arts
- World History
- On This Day in History
- Top Questions
- Week In Review
- Image Galleries
- One Good Fact
- Britannica Explains In these videos, Britannica explains a variety of topics and answers frequently asked questions.
- Britannica Classics Check out these retro videos from Encyclopedia Britannica’s archives.
- #WTFact Videos In #WTFact Britannica shares some of the most bizarre facts we can find.
- This Time in History In these videos, find out what happened this month (or any month!) in history.
- Demystified Videos In Demystified, Britannica has all the answers to your burning questions.
- Student Portal Britannica is the ultimate student resource for key school subjects like history, government, literature, and more.
- COVID-19 Portal While this global health crisis continues to evolve, it can be useful to look to past pandemics to better understand how to respond today.
- 100 Women Britannica celebrates the centennial of the Nineteenth Amendment, highlighting suffragists and history-making politicians.
- Britannica Beyond We’ve created a new place where questions are at the center of learning. Go ahead. Ask. We won’t mind.
- Saving Earth Britannica Presents Earth’s To-Do List for the 21st Century. Learn about the major environmental problems facing our planet and what can be done about them!
- SpaceNext50 Britannica presents SpaceNext50, From the race to the Moon to space stewardship, we explore a wide range of subjects that feed our curiosity about space!
- Facts & Related Content
- More Articles On This Topic
- Article History
Our editors will review what you’ve submitted and determine whether to revise the article.
- National Center for Biotechnology Information - PubMed Central - Biological effects and medical applications of infrared radiation
- LiveScience - What is infrared?
- NASA - Infrared Waves
infrared radiation , that portion of the electromagnetic spectrum that extends from the long wavelength, or red, end of the visible-light range to the microwave range. Invisible to the eye, it can be detected as a sensation of warmth on the skin. The infrared range is usually divided into three regions: near infrared (nearest the visible spectrum), with wavelengths 0.78 to about 2.5 micrometres (a micrometre, or micron, is 10 -6 metre); middle infrared, with wavelengths 2.5 to about 50 micrometres; and far infrared, with wavelengths 50 to 1,000 micrometres. Most of the radiation emitted by a moderately heated surface is infrared; it forms a continuous spectrum . Molecular excitation also produces copious infrared radiation but in a discrete spectrum of lines or bands.
What Is Infrared?
Infrared radiation (IR), or infrared light, is a type of radiant energy that's invisible to human eyes but that we can feel as heat. All objects in the universe emit some level of IR radiation, but two of the most obvious sources are the sun and fire.
IR is a type of electromagnetic radiation, a continuum of frequencies produced when atoms absorb and then release energy. From highest to lowest frequency, electromagnetic radiation includes gamma-rays , X-rays , ultraviolet radiation , visible light, infrared radiation, microwaves and radio waves . Together, these types of radiation make up the electromagnetic spectrum .
British astronomer William Herschel discovered infrared light in 1800, according to NASA . In an experiment to measure the difference in temperature between the colors in the visible spectrum, he placed thermometers in the path of light within each color of the visible spectrum. He observed an increase in temperature from blue to red, and he found an even warmer temperature measurement just beyond the red end of the visible spectrum.
Within the electromagnetic spectrum, infrared waves occur at frequencies above those of microwaves and just below those of red visible light, hence the name "infrared." Waves of infrared radiation are longer than those of visible light, according to the California Institute of Technology (Caltech) . IR frequencies range from about 300 gigahertz (GHz) up to about 400 terahertz (THz), and wavelengths are estimated to range between 1,000 micrometers (µm) and 760 nanometers (2.9921 inches), although these values are not definitive, according to NASA .
Similar to the visible light spectrum, which ranges from violet (the shortest visible-light wavelength) to red (longest wavelength), infrared radiation has its own range of wavelengths. The shorter "near-infrared" waves, which are closer to visible light on the electromagnetic spectrum, don't emit any detectable heat and are what's discharged from a TV remote control to change the channels. The longer "far-infrared" waves, which are closer to the microwave section on the electromagnetic spectrum, can be felt as intense heat, such as the heat from sunlight or fire, according to NASA .
IR radiation is one of the three ways heat is transferred from one place to another, the other two being convection and conduction. Everything with a temperature above around 5 degrees Kelvin (minus 450 degrees Fahrenheit or minus 268 degrees Celsius) emits IR radiation. The sun gives off half of its total energy as IR, and much of the star's visible light is absorbed and re-emitted as IR, according to the University of Tennessee .
Household appliances such as heat lamps and toasters use IR radiation to transmit heat, as do industrial heaters such as those used for drying and curing materials. Incandescent bulbs convert only about 10 percent of their electrical energy input into visible light energy, while the other 90 percent is converted to infrared radiation, according to the Environmental Protection Agency .
Infrared lasers can be used for point-to-point communications over distances of a few hundred meters or yards. TV remote controls that rely on infrared radiation shoot out pulses of IR energy from a light-emitting diode (LED) to an IR receiver in the TV, according to How Stuff Works . The receiver converts the light pulses to electrical signals that instruct a microprocessor to carry out the programmed command.
One of the most useful applications of the IR spectrum is in sensing and detection. All objects on Earth emit IR radiation in the form of heat. This can be detected by electronic sensors, such as those used in night vision goggles and infrared cameras.
A simple example of such a sensor is the bolometer, which consists of a telescope with a temperature-sensitive resistor, or thermistor, at its focal point, according to the University of California, Berkeley (UCB). If a warm body comes into this instrument's field of view, the heat causes a detectable change in the voltage across the thermistor.
Night vision cameras use a more sophisticated version of a bolometer. These cameras typically contain charge-coupled device (CCD) imaging chips that are sensitive to IR light. The image formed by the CCD can then be reproduced in visible light. These systems can be made small enough to be used in hand-held devices or wearable night-vision goggles. The cameras can also be used for gun sights with or without the addition of an IR laser for targeting.
Infrared spectroscopy measures IR emissions from materials at specific wavelengths. The IR spectrum of a substance will show characteristic dips and peaks as photons (particles of light) are absorbed or emitted by electrons in molecules as the electrons transition between orbits, or energy levels. This spectroscopic information can then be used to identify substances and monitor chemical reactions.
According to Robert Mayanovic, professor of physics at Missouri State University, infrared spectroscopy, such as Fourier transform infrared (FTIR) spectroscopy, is highly useful for numerous scientific applications. These include the study of molecular systems and 2D materials, such as graphene.
Caltech describes infrared astronomy as "the detection and study of the infrared radiation (heat energy) emitted from objects in the universe." Advances in IR CCD imaging systems have allowed for detailed observation of the distribution of IR sources in space, revealing complex structures in nebulas, galaxies and the large-scale structure of the universe.
One of the advantages of IR observation is that it can detect objects that are too cool to emit visible light. This has led to the discovery of previously unknown objects, including comets , asteroids and wispy interstellar dust clouds that seem to be prevalent throughout the galaxy.
IR astronomy is particularly useful for observing cold molecules of gas and for determining the chemical makeup of dust particles in the interstellar medium, said Robert Patterson, professor of astronomy at Missouri State University. These observations are conducted using specialized CCD detectors that are sensitive to IR photons.
Another advantage of IR radiation is that its longer wavelength means it doesn't scatter as much as visible light, according to NASA . Whereas visible light can be absorbed or reflected by gas and dust particles, the longer IR waves simply go around these small obstructions. Because of this property, IR can be used to observe objects whose light is obscured by gas and dust. Such objects include newly forming stars imbedded in nebulas or the center of Earth's galaxy.
- Learn more about infrared waves from NASA Science.
- Read more about infrared from the Gemini Observatory.
- Watch this video describing infrared vision , from National Geographic.
This article was updated on Feb. 27, 2019, by Live Science contributor Traci Pedersen.
Why do astronomers observe the Universe in infrared?
A guide to infrared and how it reveals the secrets of the Universe that are invisible to the human eye.
- Professor Michael Rowan-Robinson
- Share on facebook
- Share on twitter
- Share on pinterest
- Share on reddit
- Share on blogger
- Email to a friend
Infrared is a form of electromagnetic radiation exactly like visible light, but with a longer wavelength.
The infrared waveband extends from 0.8 to 1,000 microns.
In astronomy, infrared enables us to view elements of the Universe that are invisible to the human eye.
Most of the infrared radiation from the night sky is absorbed by molecules of water and carbon dioxide in the Earth’s atmosphere, though there are a few atmospheric ‘windows’, which allow observations by telescopes on the ground.
It is only from space that we can see the full splendour of the infrared sky.
Infrared was first discovered by astronomer William Herschel in 1800, when he split sunlight using a prism and measured the temperature beyond the red end of the spectrum.
We experience infrared when we feel the radiant heat from a fire or from human bodies, which we cannot see.
In astronomy, the importance of infrared wavelengths is their capacity to draw back the veil of obscuring dust that hides so much of the starlight of the Universe.
As much as two thirds of all light emitted by stars is absorbed by interstellar dust and re-emitted at infrared wavelengths.
Why is infrared astronomy used to study star formation?
Only in the infrared part of the spectrum can we really assess how much star formation is actually taking place in galaxies , and how this changes with time.
Regions in our own Milky Way Galaxy and others where new stars form are completely shrouded by dust, making infrared surveys crucial in trying to understand not just the origins of stars but of planetary systems too.
These small, sub-micron-sized dust grains are where most of the elements made in stars are stored.
The atoms of our bodies: carbon, nitrogen, oxygen and so on, were once locked up in dust grains between the stars.
Infrared observations help us to understand the composition of these grains and hence the chemical evolution of interstellar material.
They also help us to find out the physical conditions, density and temperature of the gas in regions where stars are forming.
In our Galaxy, the fraction of starlight absorbed by dust is about 30%, but when galaxies are younger this fraction is much higher.
Newly-formed stars are, in fact, totally shrouded by dust. So we can only trace out the history of star formation in the Universe by surveying in the infrared.
Using infrared to search for exoplanets
The infrared is also the ideal wavelength band to search for direct evidence of giant exoplanets and brown dwarfs – objects that are not quite massive enough to ignite nuclear burning and turn into stars.
The Infrared Astronomical telescope, IRAS, found several examples of stars surrounded by debris discs that are believed to be potential planetary systems in the making.
On the larger scale, the Japanese Akari mission searched for infrared monsters – galaxies hundreds of times more luminous than our Milky Way , which emit 99% of their output as infrared radiation.
Large-scale surveys can detect star-forming galaxies back to the first billion years of the Universe.
A second factor that drives us towards the infrared is the cosmological redshift .
The infrared Spitzer Space Telescope found galaxies with redshifts greater than six, which emit no optical light at all. Their redshifted starlight is detectable only in the infrared.
It is for this reason that the successor to the Hubble Space Telescope , the James Webb Space Telescope (JWST), is primarily an infrared instrument.
For more on this, read our guide on how JWST will observe exoplanets and how JWST will observe galaxies .
A history of infrared observations
The James Webb Space Telescope is the latest in a long line of infrared space telescopes.
The first, IRAS, surveyed the whole sky at wavelengths of 12 to 100 microns in 1983.
IRAS made discoveries in many different areas of astrophysics:
- Protoplanetary discs around stars like Vega
- Ultraluminous infrared galaxies such as Arp 220,
- Dust tori around active galactic nuclei
IRAS was followed by two observatory missions, the Infrared Space Observatory (ISO), launched by ESA in 1995, and the Spitzer Space Telescope, launched by NASA in 2003.
ISO’s 3 to 200 micron spectroscopic capability gave great insight into the nature of interstellar dust and gas in galaxies.
It also allowed astronomers to determine whether infrared radiation in active galaxies was powered by the formation of stars or massive black holes .
ISO demonstrated that interstellar dust has a rich spectrum of emission features between 8 and 20 microns, due to the effects of large molecules called polycyclic aromatic hydrocarbons, which are found on Earth in car exhausts.
The Spitzer Space Telescope, the fourth and last of NASA’s ‘Great Observatories’ was an 85cm (33-inch) cooled telescope, with three instruments spanning wavelengths from 3 to 180 microns.
The satellite trailed the Earth in a Sun-centred orbit similar to Earth’s, which allowed the telescope to escape Earth’s heat and to cool passively to an ambient temperature of 30 to 40 Kelvin (-240ºC to -230ºC), thereby saving the amount of helium coolant that has to be carried.
More like this
In terms of understanding more about the Universe through infrared observations, all eyes are now on the newly-launched James Webb Space Telescope, which should give astronomers unprecedented views beyond visible light.
Watch this space...
Types of infrared
Infrared is subdivided into four sub-bands:
- Near infrared, stretching from 0.8 to 3 microns
- Mid infrared, from 3 to 30 microns
- Far infrared, from 30 to 200 microns
- Sub-millimetre infrared, from 200 to 1,000 microns
In each band we see different sources of radiation.
In this optical view of galaxy M81, we see the young, massive blue stars in the spiral arms, as well as the old red stars of the bulge. This was taken from the ground-based Kitt Peak Observatory.
In the near infrared we see light from old stars, like red giants, with surface temperatures around 3,000 Kelvin (2,700ºC).
The near infrared image of M81 is dominated by old stars, so the bulge is very prominent. This Spitzer image is virtually unaffected by the obscuring dust.
In the mid infrared we see emission from hot dust, with temperatures from 300 to 1,000 Kelvin (30 to 700ºC).
This is also where the objects of the inner Solar System – the inner planets , asteroids and comets – emit their thermal radiation (we also see these at optical wavelengths through their reflected sunlight).
In the mid infrared image of M81 we see the emission from dust clouds, where new stars are forming, so the spiral arms are again prominent. Alongside the optical view, the difference is striking.
In the far infrared we tend to see cooler dust, at 30–100 Kelvin (-240 to -170ºC). This is where the thermal emission from dusty galaxies tends to peak.
In the far infrared image of M81 we see the cooler dust, both in the star-forming clouds and in the more diffuse interstellar medium. Clumpy knots show where stars are being born.
In the submillimetre we find that cool objects, with temperatures in the range 3–30 Kelvin (-270 to -240ºC), tend to be prominent. Dusty galaxies at high redshift have the peak of their emission shifted from the far infrared to the submillimetre.
A timeline history of infrared astronomy
William Herschel detects IR radiation by passing sunlight through a prism and measuring each colour’s temperature. It’s highest beyond the visible spectrum.
Charles Piazzi Smyth, Scotland’s Astronomer Royal, detects IR radiation from the Moon while in Tenerife. Better observations are possible at higher altitudes, proving that the atmosphere absorbs infrared.
Infrared observations by Adriaan Wesselink show that the Moon is covered with a fine dust, years ahead of the Apollo missions between 1969 and 1972, which increased our knowledge of the Moon still further.
Harold Johnson develops infrared detectors to study the infrared radiation of stars at the McDonald Observatory in Texas. He also devises a system to measure infrared magnitudes.
Gerry Neugebauer and Robert Leighton do the first infrared survey of the sky from Mount Wilson Observatory. They found about 20,000 sources, including star-forming regions, galaxies and stars.
The Infrared Astronomical Satellite (IRAS) becomes the first IR space mission. This US-Dutch-British project is a success and inspires NASA and ESA to approve new space-based observatories.
An infrared telescope is set up in Antarctica. The colder temperatures found there make the South Pole Infrared Explorer (SPIREX) more sensitive to incoming infrared radiation.
Europe launches the Infrared Space Observatory (ISO). It lasts for two-and-a-half years. A highlight is the beautiful IR spectra of stars, galaxies and interstellar dust and gas it captures.
NASA launches the Spitzer Space Telescope, with advanced detectors generating images of galactic nebulae and some of the most distant galaxies.
Light from a planet outside our Solar System is directly detected for the first time. Spitzer captures the infrared light from two planets over 700ºC, both so-called ‘hot Jupiters’.
The Japanese Space Agency (JAXA) launches Akari, first known as IRIS and then ASTRO-F. Its first images of galactic nebulae demonstrate its vastly superior angular resolution compared to IRAS in the 1980s.
The launch of the James Webb Space Telescope, the latest mission that will give astronomers an unprecedented view of the Universe in infrared.
Professor Rowan-Robinson is an astronomer, astrophysicist and Professor of Astrophysics at Imperial College London.
Just £4 per issue when you subscribe today!
- Give this article Give this article Give this article
How Infrared Images Could Be Part of Your Daily Life
In a post-quarantine world, heat sensors could help spot sick people with elevated temperatures as they enter public places. But it’s not that simple.
By Jonah M. Kessel
Welcome to Maplewood, N.J. … in infrared.
As the country reopens, you might start seeing more images like these: real-time heat maps that could find sick people, before they know they are sick. And in a post-quarantine world, you might start having your temperature taken. A lot.
See the cross hair below? That’s where this camera is taking a temperature reading.
A fever is one indicator that someone may be exhibiting coronavirus symptoms, and the Centers for Disease Control and Prevention recommends temperature screenings in a variety of environments, including schools and businesses .
As shelter-in-place restrictions vary across many cities and counties around the country, officials have begun buying technology like infrared cameras in the hopes of helping track and contain the spread of the outbreak.
I’m a video journalist at The New York Times, and last year, I was trained to use infrared cameras for an article that exposed immense methane leaks at oil and gas facilities, worsening global warming.
When the pandemic took hold, I started seeing more and more companies like Amazon using this technology to help identify sick people in their warehouses. Thermal imaging cameras are beginning to appear in Subway restaurants. Carnival Cruise Lines, whose ships became hot spots for the virus’s spread, said all passengers and crew would be screened when it began sailing again.
The rapid adoption of infrared technology had me wondering how helpful it could be. Several systems are being rolled out, including camera-based ones and others that make people walk through thresholds like metal detectors. Could they actually help contain the spread of the virus while we wait for a vaccine?
A Harris Poll conducted in late March, just after the majority of the shelter measures went into place across the United States, found that 84 percent of respondents favored mandatory health screenings to enter public places.
I got my hands on a temperature-reading infrared camera and hit the streets of Maplewood on a hot summer day last week. I wanted to understand where the camera succeeds and where the challenges are in capturing accurate temperature readings.
Maplewood is part of Essex County. There have been over 18,000 confirmed cases in the county, and over 1,700 related deaths. But like many places in the country, Maplewood is opening back up — albeit mostly outdoors. Streets once filled with cars are now partly filled with outdoor seating for restaurants.
Here’s how to understand these images: The first image above shows a woman who ordered something warm to drink. The waitress hands her a bright white cup. The second image shows a woman nearby eating ice cream. The ice cream is dark blue. It means that white = hot; dark = cold.
So, does it work? Yes, but it’s not so simple.
Even a working infrared camera system won’t detect many people who may have the virus but aren’t exhibiting symptoms.
But equally important is how the cameras are used.
A hypothetical situation goes something like this: A factory opens its doors and thousands of workers pour in. Above them, infrared cameras point to individuals in a big crowd and pick out the sick people.
This, however, would not produce accurate results, according to experts.
“The problem with crowd scanning is we know temperature measurements are impacted by the distance from camera to target, and crowds are different distances away,” said Chris Bainter, the director of global business development for FLIR, a maker of infrared technology. “The cameras don’t focus from three feet or six feet away to infinite with everything in focus.”
“Where you measure has a big impact, and studies have shown the tear duct is the best place,” he added. “If you are looking at a crowd of people, are you getting an accurate reading?”
The real version of this technology goes something like this. One camera, one subject. Here’s my wife on our stoop.
I can point the camera at her, but to get a more accurate temperature reading, the cross hair needs to be right in the subject’s eye socket. A bit to the left or a bit to the right and you’ll see a different temperature. This is important because it changes the time it takes to get someone’s reading.
There are other factors to consider. “Core body temperature has slight variation from person to person,” Mr. Bainter said. “What’s normal for me might be different than you. And that can be driven by age, gender, ethnicity, diet or recent exercise. And then there’s some environmental factors. Throughout the day, your body temperature changes from the morning to the afternoon.”
The day I was filming in Maplewood, temperatures were around 95 degrees. Everyone was running hot. Some surfaces, like the bench below, were nearly 100 degrees.
The growing use of the technology has raised privacy and other concerns.
Civil liberties experts have warned about data being collected on employees and used without their permission. Democratic and Republican lawmakers have proposed bills to help protect people’s information and privacy as data like temperature readings is collected, but the legislation has so far stalled in Congress.
“The road to hell is paved in good intentions, and the mass rollout of cameras should be seen for what it is: the mass rollout and further normalization of cameras,” said Ed Geraghty, a technologist at Privacy International , a British nongovernmental organization focused on privacy rights.
“We already see police repurposing streetlight cameras, put in place to monitor traffic and environmental data, in order to form criminal cases against those accused of vandalism — it would be naïve to believe the same will not be the case with these cameras,” he added.
All of this being said, could this technology work if used correctly? Yes. Is it better than nothing? It depends who you ask. But while we wait for a vaccine to be made, many see the benefits.
But will throwing infrared cameras up all over society make us safer from the virus? How might a grade school student react to seeing a classmate set off an infrared-based alarm walking into school? Will the time it takes to screen everyone trying to get into a building create problems for schools or offices? These are important questions that we will face in a post-quarantine world.
And some aren’t so hypothetical. Across the country in Mission, Texas, school administrators debated the merits of using infrared to screen students as they come in the door.
On June 15, during a board meeting for the Sharyland Independent School District , officials deliberated the use of the SafeCheck Walkthrough Body Temperature Detector , which measures temperatures from the wrist or forehead.
“In the event that we have to take each student’s temperature when they walk in to the door, that’s 700 kids, and we have one nurse, typically on staff, at each campus,” said the district’s chief financial officer, Ismael Gonzalez. “They are saying this can pick up 70 kids a minute.”
A week later, the school board approved spending $178,488 for the devices .
- Ben Recommends
- Ben’s Story
- Low Carb & Ketogenic Diet
- Sabbath Ramblings
- Ben’s Music
Forget Everything You Think You Know About Calories, Eating, ATP & Cellular Energy – How Light Actually Creates Energy In Your Cells.
- March 29, 2021
- Posted by jojo
March 30, 2021
The first report of using red or infrared light therapeutically came in 1967 when a Hungarian physician and scientist named Endre Mester, AKA the “father of photobiomodulation,” was trying to simulate burn injuries on mice using red and infrared light to see whether the recently invented laser caused cancer. To his surprise, Endre found that hair grew back faster on mice in the treated group than in the untreated group —and that the laser, in fact, did not, contrary to popular belief, cause cancer.
Almost sixty years later, health enthusiasts, biohackers and medical clinics alike are using red and infrared light therapy devices for everything from enhancing testosterone and cognition to promoting better sleep and red light devices have hit the mainstream as a remedy for headaches , plantar fasciitis , hair loss , and beyond.
As you probably know, I’m no stranger to these devices myself. Heck, just last week, on my Q&A Podcast 425 , I talked about how, upon waking, the first thing I do is grab my Joovv GO (which has a handy new feature that allows it to double as a sunrise alarm clock) off my nightstand, lift up the covers, and set it right between my legs to “bathe my balls” for a few minutes in testosterone-boosting red and near-infrared light as I do my morning reading.
OK, I'll admit that's a bit fringe. But additionally, I’ve covered all sorts of light-related topics that go beyond ball-blasting in articles and podcasts such as…
- Ben Accidentally Gets A Bit High On Ketamine & Talks About His Journey Of Biohacking, Ancestral Health, Spirituality, Fitness & Much More With Light Expert Matt Maruca.
- The Danger Of Smart Drugs & The Rise Of Photobiomodulation As A Brain-Boosting Nootropic.
- Is The Sun The Ultimate Source Of Health & Vitality Or Just A Giant Orange Cancer Circle In The Sky?
- What Time Of Day Can You Eat A “Cheat Meal,” How Cold Can Make You Unstoppable, Lies We’ve Been Led To Believe About Sunlight & Much More!
- What’s The Deal With Fancy Red Light Devices? Your Go-To Guide On How To Use Red Light To Enhance Testosterone, Skin, Recovery, Cognition, Sleep & Beyond!
- Sunlight Makes You Skinny & Blue Light Makes You Fat: 11 Ways To Biohack Light To Optimize Your Body & Brain.
- Shining Laser Lights On Your Balls & Beyond: Photobiomodulation 101 – How To Use Near Infrared & Red Light For Collagen, Thyroid, Muscle, Skin & More.
- How Modern Lighting Can Destroy Your Sleep, Your Eyes & Your Health (& What You Can Do About It).
- How To Use Low Level Light Therapy and Intranasal Light Therapy For Athletic Performance, Cognitive Enhancement & More.
…and then most recently on my podcast “ Light As Medicine, Metabolic Typing, COVID Controversies, Polar Bear Fitness, Healing Yourself With Laughter & More With Dr. Leland Stillman. ”
Board-certified in internal medicine and specializing in integrative medicine, Dr. Stillman has a passion for doing whatever it takes to discover the root cause of his patients' medical problems, then addressing their medical issues by focusing on all aspects of the environment they live in, which includes—you guessed it—light.
In today’s article, a guest post by Dr. Stillman, you’ll discover how light creates energy within your cells, how your brain biohacks itself with light, why melatonin is not just for making you sleepy, the problem with modern society's shift away from natural, and towards artificial , lighting (and what you can do about it), how you’ve been misled about the sun’s role in skin cancer, and much more.
How Light Creates Energy Within Your Cells
Forget everything you learned in biology class about the bioenergetics of life.
The conventional view of cellular energy generation—that your body breaks down food to release energy, then harnesses that energy to create a molecule called adenosine triphosphate (ATP)—is at best, a half-truth.
In 1962, Gilbert Ling, Ph.D., published a paper on what he called his “ Association-Induction Hypothesis. ” Ling’s hypothesis was that “structured” water generated the energy necessary to run the mammalian cell. Ling went against the commonly held dogma surrounding ATP by pointing out that the cell could not meet its energetic needs based on the energy found in ATP alone. If the energy stored in ATP could not meet the energy demands of the cell, then where did the rest of the energy come from?
There had to be another way for cells to generate energy.
Several decades later, the answer is now clear. Gerald Pollack, Ph.D. , a physical chemist at the University of Washington and the founding editor in chief of “ Water: A Multidisciplinary Research Journal ,” picked up where Dr. Ling left off and has spent the last few decades researching exactly how life uses light to create energy. His answer is that light structures water to provide energy for the cell to perform its vital processes. This structured water then interacts with the enzymes and proteins that run cellular machinery to augment their functions. This answer sounded so far-fetched at its inception, decades ago, that it was ridiculed and ignored. But, the idea has stood the test of time and now has been validated by some of the world’s foremost experts on water and biophysics .
Most people think of enzymes and proteins as if they were simple machines, but if that were true, you would be a simple machine. We cannot shine a light on a simple machine and change its function, but we now know that we can do that to living systems. Enzymes and proteins are made up of amino acids—carbon, nitrogen, oxygen, and hydrogen—bound together by electromagnetic force. That force is readily transmuted into light (any electrical light is simply a device that transforms electrical current into photons, or light). Light, in turn, can be transformed into electricity; this is what a solar panel does. When light strikes an enzyme, it interacts with these charged particles in ways that are difficult to detect in physical terms, due to the extremely small scale on which these changes happen. But, in the case of enzymes and proteins, we can evaluate how light is affecting their function by measuring the processes that they perform. Take the mitochondria, as one example. Your mitochondria use many different proteins and enzymes to generate energy. When illuminated with the right light, the efficiency of mitochondria can be improved . There is debate as to whether the enzymes and proteins, or the water that surrounds them, are the site of action of light. Different energies and frequencies can change the quantum structure of biological systems, and therefore different energies and frequencies can alter the functioning of those systems.
So, how does this work in practice?
To get some idea of the therapeutic potential, it might be helpful to start with what we know about the consequences of misusing light. Artificial light at night alters circadian rhythms, which increases your risk of depression , irritable bowel syndrome , metabolic dysfunction , hormonal imbalances , multiple sclerosis , and cancer . For more on the dangers of artificial light, check out Ben's article “ Sunlight Makes You Skinny & Blue Light Makes You Fat: 11 Ways To Biohack Light To Optimize Your Body & Brain. ”
On the other hand, when you correct an unhealthy, artificial light environment, you'll see improvements in everything from sleep to overall health—as I've witnessed firsthand with many of my patients. Additionally, light therapy is now being studied extensively in cancer research because it holds promise both for destroying cancer cells and for helping cancer patients to heal from the side effects of modern cancer treatments . If artificial light at night can cause disease, then it stands to reason that correcting your light environment can effectively treat these diseases. When you illuminate your cells with the proper light, you can increase the rate of energy generation to speed wound healing , hair growth , and neurotransmission , strengthen muscle contraction, and more.
How Your Brain Biohacks Itself With Light
In a 2019 paper in the journal Melatonin Research, Scott Zimmerman and Russel Reiter state, “The brain appears to be optically designed to distribute near-infrared photons to the grey matter even down into the folds of the brain…” The structure of the brain is no accident. What Zimmerman and Reiter are saying is that the brain is organized, based on our most advanced concepts of optics, to optimize near-infrared photon delivery to the grey matter—the area of your brain responsible for muscle control, vision, hearing, memory, emotions, speech, decision making, and self-control.
Why might the brain be organized in this way?
The answer lies in how your cells use light to generate energy, as detailed by Gerald Pollack, Gilbert Ling, and many more. Two frequencies of light excel in structuring water, and these are red and infrared light. These two frequencies also do not disrupt circadian rhythms in the same way that blue and green light do—making them optimal for supporting energy generation within your body.
We absorb much of this light from emitters outside of ourselves, i.e., that big flaming ball of gas and plasma in the sky. More than 50% of sunlight is in the red or infrared spectrum (this varies with latitude and meteorological conditions). Look at a sauna or hot spring through a thermal camera, and you’ll see what your body perceives as heat: infrared light.
We have been obsessed with these frequencies since the beginning of time, and yet only now can we explain why at a quantum level.
See, your body also generates light within its cells. Your mitochondria generate light based on changes in the energy levels of quantum particles (electrons and protons). The burning of energy within a cell is a combustion reaction that liberates infrared and red light from the substrates (fats, proteins, and carbohydrates). How much energy a cell can generate depends upon a range of factors like pH (acidity vs alkalinity), salinity, temperature, electrolyte concentrations, genetics, and epigenetics. At extremes of any one of these parameters, energy generation becomes impaired.
Your brain consumes approximately 15% of your cardiac output and is responsible for approximately 20% of your body’s total metabolic activity, yet it weighs about three pounds (around 2% of your body weight). It is ten times more metabolically active, on average, than the rest of your body’s tissues. Not surprisingly, it contains an enormous number of mitochondria. A single neuron may contain thousands of mitochondria. When they degenerate, i.e. when their photonic output drops, your brain stops working.
This is part of why we are dealing with epidemics of illnesses of the skin, eyes, and brain—organs that are all exposed to light and reliant upon a healthy light environment.
We have moved indoors, out of the sun, and we no longer use saunas or spend time in hot springs. We have even gotten rid of incandescent bulbs in favor of fluorescent or LED bulbs, which emit zero infrared and often very little red light. We have removed infrared light from our modern world to the greatest degree possible, without realizing just how important this frequency of light is to our health. Ben covers many of the perils of modern lighting (and what you can do about them) in this podcast with Ben Greenfield and Matt Maruca .
Light, Melatonin, and Your Mind
Melatonin is the hormone of light, and it is essential to maintaining the mitochondria that illuminate your mind, along with a host of other functions Ben discusses in this podcast with Dr. John Lieurance .
Synthesized during the day in response to light , melatonin is produced and utilized in different parts of your cells, in response to different stimuli, at different times of day.
The analogy I draw to explain how melatonin is used is how you use water in your home. You turn on the faucet in your bathroom to wash your hands, the shower to bathe, and the kitchen sink to do the dishes. You probably tend to do this during the day. You apply water in different ways, in different parts of your home.
For a similar reason, the production and movement of melatonin in living systems are also tightly regulated. You wouldn’t leave your shower or sink running when you weren’t using them, would you? This is why I am generally against melatonin supplementation in the form of a pill. This, in my opinion, is the equivalent of trying to use the fire hydrant outside of your house to do the dishes. Your body’s regulation of melatonin is exquisite and should be controlled by light (although melatonin supplements do have their place in certain clinical contexts).
While melatonin is synthesized during the day in response to light, it is not present in the serum during the day. At night, and specifically after three to four hours in the absence of blue and green light, melatonin is released into the bloodstream where it is carried around your body to turn on your cellular rest and repair mechanisms. This means that looking into a brightly lit screen in the hours before bed and then popping a melatonin tablet before sleep is like pressing down on the gas pedal and the brake at the same time. It makes no biophysical sense. This is also why you should wear dark red or orange blue-light blocking glasses three to four hours before your typical bedtime.
Aside from making you feel sleepy, melatonin also protects your mitochondria from oxidative damage by scavenging free radicals and turning on mitochondrial repair and regeneration pathways . Free radicals, also known as reactive oxygen species (ROS), are the main source of long-term damage to living organisms. They are the key mediators of aging, and melatonin is the main endogenous means of neutralizing them. Chronic exposure to artificial light at night is linked to premature aging and disease due to these effects on circadian rhythms, which are mediated by melatonin .
Melatonin also indirectly controls all of the other hormones and neurotransmitters that your brain depends upon. It is the master circadian regulator and as such, it influences and (arguably) controls all other hormones and neurotransmitters. For example, abnormally high levels of melatonin have been documented to completely suppress sex steroid hormone production . Essentially, without energy from your mitochondria, you would not have the energy to produce hormones and neurotransmitters. Optimizing melatonin levels is the cornerstone of optimizing metabolism.
A naturalistic lighting environment is essential for optimal melatonin production during the day and for optimal melatonin activity at night. The key is bright light during the day and as little artificial blue and green light as possible. To achieve a healthy light environment, you can use blue-light blocking glasses ; light-blocking tape on your light-emitting electronics; blue light filter apps or IrisTech software on your computer , tablet, and smartphone; Driftbox blue-light filter for your tv; and clear incandescent bulbs (preferably without any coating, which changes the beneficial wavelengths) or low-blue-light bulbs throughout your home.
Burning Out On Biohacking
Practically every biohack you have ever heard of helps your mitochondria emit more light in order to meet the bioenergetic demands of your body. Methylene blue , cold therapy , and intermittent fasting —just to name three of the most popular—all alter mitochondrial function, and therefore light emission.
But beware, most biohackers have no idea that they can actually burn out the metabolic pathways they rely upon to generate energy.
This is why my practice now largely consists of burned-out biohackers—people who have done everything from moving to Mexico in search of stronger sunlight to spending hours a week in ice-cold water.
How do they burn out?
Whenever you subject your body to stress or change its environment, it responds by altering internal biochemical processes. For example, when you immerse yourself in cold water, specialized fat tissue in your body starts to burn carbohydrates and fats to generate heat. This response requires activation of the sympathetic nervous system, which runs on dopamine, epinephrine, and norepinephrine. These amino acids are produced from the amino acid tyrosine. Whenever you create the demand for these amino acids by activating the sympathetic nervous system (as you do with cold exposure), you must increase the supply. Likewise, to burn fat to generate heat, your body uses the carnitine shuttle system to move those fats into your mitochondria. What can happen with excessive stress of any kind, such as cold exposure or psychological stress, is the exhaustion of these amino acids. I routinely see low tyrosine levels in people who have been exposing themselves excessively to cold. I also see signs that their carnitine shuttle has burned out, and therefore their mitochondria must rely on sugar, rather than fat, to generate energy.
Stressing your body without quantifying its resources is like stepping on the gas when you have no idea what the fuel level is in your gas tank. This is why light alone is not the solution to complex neurological problems, but it is a powerful tool that you can use to help your mind achieve optimal performance.
In this age of slathering sunscreen from head to toe all day long, it may surprise you to read that avoiding sunlight is a risk factor for death that is equivalent to smoking . Yes, supposed “health-conscious” people make a point of never smoking, but they think nothing of living indoors 98% of the time. Sunlight exposure has been linked to lower risks of cancer , diabetes , obesity , depression , autoimmune diseases , autism , and allergies . For this reason, prudent sun exposure is a healthy habit.
But what about skin cancer?
In a large study in Sweden, “ The mortality rate amongst avoiders of sun exposure was approximately twofold higher compared with the highest sun exposure group, resulting in excess mortality with a population attributable risk of 3% .” This does not mean you should go out and get sunburned: sunburn and excessive tanning bed use are both linked to premature skin aging and skin cancer, which is why I don’t recommend either. Healthy doses of sun exposure have actually been shown to potentially reduce mortality due to melanoma. (Yes, this study actually found that “ sun exposure is associated with increased survival from melanoma. ”)
How is this possible?
UV light in sunlight drives vitamin D production, and the authors of that study suggest that, “the apparently beneficial relationship between sun exposure and survival from melanoma could be mediated by vitamin D.” What the authors of that paper may not have been aware of is that melatonin may play a part as well, as it seems to protect us from skin cancer . This is why I tell my patients, “If the sun causes skin cancer, then spoons make people fat.” Healthy sun exposure means avoiding sunburn, while still getting enough sun to maintain optimum vitamin D levels.
What about sunscreen?
Sunscreen may cause more harm than good—effective at preventing sunburn, but sunscreen to protect against skin cancer is a completely different story. Many of the chemicals in sunscreen are toxic, and it remains an open question as to whether many sunscreens could promote skin cancer . Even the Environmental Working Group has published a guide on sunscreen that points out many of the flaws in the simplistic narrative that “sunscreen prevents skin cancer.” If sunscreen prevents skin cancer, then throwing out your spoons prevents obesity. Sunscreen can prevent sunburn, and we have every reason to believe that it could therefore prevent skin cancer, but not all sunscreens are the same. This is why I personally use a physical barrier zinc oxide sunscreen rather than a chemical sunscreen.
With that said, there is a downside to even natural, physical sunscreens, which is that they often block UVB as well as UVA rays. This means that using any sunscreen, physical or chemical, can prevent you from producing vitamin D, which is essential for good health, including the prevention of skin cancer. I always counsel my patients that prudent sun exposure—avoiding burning, rather than avoiding the sun entirely—is vital to a long and healthy life. Learn more about sunscreen in Ben's podcast “ Top 12 Keto Myths, The Dark Side Of Tabatas, Dad Bod, Healthy Sunscreen Alternatives & More! ” and his article “ Sunscreen: Is The Risk Worth The Reward? ”
Bringing Red and Infrared Light Back Into Our Modern World
There’s no doubt that red and infrared light are essential to good health, but saunas and hot springs are not exactly convenient, affordable, or practical solutions for most people.
So, how can you bring red and infrared light back into your modern life?
The most convenient solution for restoring red and infrared light is via light therapy devices. You’re no doubt familiar with devices like the Joovv devices that Ben mentioned earlier. Some of the many benefits you could expect to experience from such devices include:
- Improvements in skin tone and complexion, and diminished signs of aging .
- Natural collagen production boost .
- Improvements in fine lines and wrinkles .
- Therapeutic effect on symptoms of psoriasis, herpes, and acne .
- Muscle thickness and strength improvements (by over 50%) .
- Pain reduction (70%) in people suffering from rheumatoid arthritis .
- Improved sleep and cognition, including better executive functions, improved social functioning, improvements in depression, anxiety, headaches, and an increased ability to perform tasks and activities .
- Better healing of wounds, burns, and scars .
- Increases in natural melatonin production .
Similar to the Joovv , I have EMR-Tek Firestorm and Inferno devices in my office. Every day after I shower, I turn on these lights for ten to twenty minutes while I work at my standing desk. In those ten or twenty minutes, I get more red and infrared light than most office workers get in an entire day, or even an entire week. I recommend them to my patients, and the further from the sun they live (the further north or south from the Equator), the more they need it. The Inferno puts out approximately 50,000 lux at 6 inches, and that isn’t even counting the infrared light that it emits (which is measured differently, since it is not visible light). On a sunny day at my latitude (Richmond, Virginia), the mid-day sun is around 50,000 lux. On a cloudy day, it’s between 5,000 and 10,000.
The average seasonal affective disorder lamp puts out about 10,000 lux, but only at the surface of the lamp. I find it funny that lamps that are supposed to make you happy are still only as bright as a cloudy day.
You can learn more about red light devices in Ben’s article “ What’s The Deal With Fancy Red Light Devices? Your Go-To Guide On How To Use Red Light To Enhance Testosterone, Skin, Recovery, Cognition, Sleep & Beyond! ”
Another option that has benefits specific to the brain, is the Vielight , a transcranial laser stimulation device that uses the optimal frequency of infrared light to promote energy generation within the brain. In one controlled study using a Vielight, subjects demonstrated significantly improved memory and mood. This treatment method also showed improvements in executive functions . Other studies on transcranial laser stimulation devices showed improved attention-biased modification (ABM) in people with depression as well as improved reaction times .
You can learn more about the Vielight in Ben’s article “ The Danger Of Smart Drugs & The Rise Of Photobiomodulation As A Brain-Boosting Nootropic. ” and in his podcast “ How To Use Low Level Light Therapy and Intranasal Light Therapy For Athletic Performance, Cognitive Enhancement & More. ”
The fundamental importance of light for optimal health and performance is at long last starting to be understood and appreciated by doctors, scientists, and the general public.
Light is one of the secrets to my success in cases where other clinicians have failed. I believe it will change the world of medicine and make obsolete medicines that today are making the pharmaceutical industry billions of dollars (which might be why it has remained a well-kept secret for so long).
It is no coincidence that the structure of your brain optimizes infrared light delivery to the grey matter. When you illuminate your cells with the proper light, you can increase the rate of energy generation, resulting in a host of positive effects on your body. As the primary driver for energy generation within your cells, and one of the most promising new technologies to treat everything from hair loss to low testosterone to psychiatric and neurological diseases, light's effects on your body’s systems are undoubtedly critical and wide-ranging.
Light is nature’s perfect medicine.
Conversely, lack of exposure to proper light can be the catalyst for disease and dysfunction. Artificial light exposure at night— specifically blue and green wavelengths—suppresses melatonin release at night, ruins circadian rhythms, and prevents melatonin from repairing and rejuvenating your body.
Thoughtful exposure to sunlight has been linked with lower rates of cancer, diabetes, depression, and other major conditions. In addition to natural sunlight, the most effective and convenient solution that I’ve found for increasing therapeutic light is light therapy devices such as the Joovv , EMR-Tek lights , and the Vielight , along with the use of infrared sauna therapy .
A thorough understanding and application of proper light has allowed me to treat patients who have been considered incurable. I believe that light will change the future of medicine, and that light’s therapeutic potential is limitless.
Light shapes life—how is it shaping yours?
If you’d like to learn more about how to use light to biohack your way to wellness, you can apply to work with me directly at StillmanMD.com .
Leave any comments, questions, thoughts, or experiences you have had with light, the sun, photobiomodulation, or anything else covered in this article below, and I’ll get back to you.
I would like to thank Dr. Anthony G. Beck , for mentoring me in the use of phototherapy in my practice, his advice has proven invaluable; and Dr. Jack Kruse , for his work in explaining to the world just how powerfully light shapes life, and specifically human health and disease.
Ask Ben a Podcast Question
2 thoughts on “ Forget Everything You Think You Know About Calories, Eating, ATP & Cellular Energy – How Light Actually Creates Energy In Your Cells. ”
Amazing! I use the Firestorm by EMR Tek and it’s a really game changers. It level up my energy.
It’s somewhat ironic that your practice largely consists of burned-out biohackers. The people who spend the most time, money and effort in an attempt to be healthy sometimes end up becoming more unhealthy than your average Joe from doing too much. (I have been guilty of overdoing it several times.)
I get it that Professional and Olympic athletes may want to try to figure out every tip, trick and practice to maximize training without over training. For everyone else it would seem that the most simple solution to putting too much stress on the body is to simply dial down the intensity.
Leave a Reply Cancel reply
Your email address will not be published. Required fields are marked *
Please note that Internet Explorer version 8.x is not supported as of January 1, 2016. Please refer to this page for more information.
IRT is a nondestructive and contactless method that can provide information about the exact physical location of an occurring fault, which allows for posterior electrical diagnosis of the problem.
From: Photovoltaic Solar Energy Conversion , 2020
- Fibre Reinforced Polymer
- Non-Destructive Testing
Repair of deteriorated bridge substructures using carbon fiber-reinforced polymer (CFRP) composites
M.E. Williams , in Advanced Composites in Bridge Construction and Repair , 2014
9.6.3 Infrared thermography
Infrared (IR) thermography is the science of acquisition and analysis of thermal information from non-contact thermal imaging devices. IR thermography detects emitted radiation in the infrared range of the electromagnetic spectrum. This corresponds to wavelengths longer than the visible light portion of the spectrum. Thermal imaging can therefore be utilized to detect defects in the CFRP installation that may not be visible. Voids or delaminations in the CFRP installation are shown with a unique thermal signature due to entrapped air between the CFRP composite and the concrete substrate. As shown in Fig. 9.16 , CFRP delaminations exhibit a dark thermal signature in comparison to well bonded CFRP applications. As such, defects were marked and subsequently repaired after thermal inspection.
9.16 . Areas of CFRP delamination identified by infrared thermography (black spots).
A review on condition monitoring system for solar plants based on thermography
Álvaro Huerta Herraiz , ... Fausto Pedro García Márquez , in Non-Destructive Testing and Condition Monitoring Techniques for Renewable Energy Industrial Assets , 2020
Infrared thermography can be carried out using two different approaches:
Pulsed thermography is the most common type of thermal stimulation due to its easy and rapid application. A body is heated with a heat pulse and the temperature data are collected when temperature decreases. Heat sources that can be used include lamps, heating gun, flashes, … 
Lock-In thermography employs an oscillating temperature field to heat the object. In case of internal failure, the waves alter  . A synchronisation between the input signal (thermal source) and the output signal (thermographic signal) is required.
Long-Pulse (Step Heating) thermography, employs a continuous low power heat source  . The main different with respect to pulsed thermography is the target. Long-pulse is focused on the cooling process whereas pulse thermography evaluates the heating process.
Vibrothermography  uses mechanical vibrations to generate hot spots in the areas where cracks, voids, or other defects are located. The mechanical energy is converted into thermal energy inside of the material.
Passive Infrared Thermography: This infrared technique does not need an external source of heat. The infrared radiation emitted by the object already is collected instead.
Test Methods, Nondestructive Evaluation, and Smart Materials
PAUL T. CURTIS , in Comprehensive Composite Materials , 2000
Infrared thermography is a slightly more exotic technique than the others but one particularly suitable for the study of damage development during fatigue loading of composite materials. It has the advantage that the inspection requires no interruption of the fatigue test. The resolution obtainable depends on the equipment, but is typically similar to that obtainable with ultrasonics and rather less than can be achieved with X-radiography. The technique can detect heat generated from two sources, hysteresis heating, usually emanating from the resin or interface, and frictional heating as a result of differential movement at cracks.
Non-destructive evaluation (NDE) of composites: application of thermography for defect detection in rehabilitated structures
A. Shirazi , V.M. Karbhari , in Non-Destructive Evaluation (NDE) of Polymer Matrix Composites , 2013
Infrared (IR) thermography provides the ability to obtain real-time inspection capabilities in the field which when coupled with data interpretation provides a means of rapid assessment of the integrity and future serviceability of a rehabilitated structure. The chapter provides details on a program that enables the detection of defects and the establishment of a standardized protocol for quantifying progression of these defects in FRP rehabilitated concrete structures. The use of IR thermal imaging, using a means of progressive testing and a mathematical model from a time history of the thermal responses is shown to provide valuable information pertaining to the life-span of FRP rehabilitated systems.
Nondestructive Testing With Infrared Thermography
Carosena Meola , ... Giovanni maria Carlomagno , in Infrared Thermography in the Evaluation of Aerospace Composite Materials , 2017
4.1 Historical Groundings
Infrared thermography (IRT) has taken its first steps right in the nondestructive testing (NDT) field. In fact, signs of its use for NDT tasks were traced by Vavilov  up to the beginning of the last century when the first infrared detector was patented by Parker in 1914  . The proposal for using a complete IR system for detection of forest fires came from Barker in 1934  . In the meantime, Nichols performed one of the first industrial applications  , which consisted of checking the heating uniformity of steel strips. An innovative study on thermal nondestructive testing (TNDT) was performed by Green, who developed a technique for checking nuclear reactor fuel elements  . In the 1960s, the very first commercial infrared system (AGA Thermovision) entered the market; it was first used for the inspection of electric/electronic components and later implemented for nondestructive purposes such as testing of the Polaris rocket motor  and nuclear reactor fuel elements  . In the meantime, IRT also started to become attractive for use in the aerospace field.
In 1966 the American Society for Nondestructive Testing (ASNT) published the first edition (ASNT SNT-TC-1A) of the Recommended Practice to provide guidelines for personnel involved in nondestructive tests. In this first edition, the document involved only five methods: ultrasonic testing, magnetic testing, liquid penetrant testing, eddy current testing and radiographic testing. IRT was added much later, in 1992, as an emergent technique and it was fully recognized in 2007 when the ASTM E2582 practice, concerning application of flash thermography for inspection of aerospace composite panels, was released  .
However, the first approaches were somewhat deceiving, being rather qualitative, so interest was turned toward other NDE techniques such as ultrasonics. This happened mainly because of lack of basic knowledge regarding the output of the infrared imaging device and the thermal behaviour of the part under inspection. At that time there were no well-assessed testing procedures and the interpretation of thermograms was rather difficult. It was only later (beginning in the 1980s), thanks to the comprehension of heat transfer mechanisms  , that IRT received renewed attention. A thermophysical approach has been developed by many scientists (amongst others, Carlomagno, Balageas, and Vavilov) who introduced one- (1D), two- (2D) and three-dimensional (3D) models of defects detection. From that time on, there has been a proliferation of ideas regarding both hardware and software means for setting up an effective technique, which is now amongst the well-recognized NDE techniques in the aeronautical field. For more details, the reader is addressed to international standards, like the NAS 410, or ISO 9712.
Failure modes in structural applications of fiber-reinforced polymer (FRP) composites and their prevention
O. Gunes , in Developments in Fiber-Reinforced Polymer (FRP) Composites for Civil Engineering , 2013
5.4.3 Infrared thermography and digital shearography
Infrared thermography (IRT) and digital shearography (DISH), also known as speckle pattern shearing interferometry (SPSI), are both optical techniques that enable non-contact, full-field, real-time, and rapid non-destructive testing; but these methods are fundamentally different in their damage detection principles. Thermography measures a material’s heat transfer response to thermal effects while shearography measures a material’s mechanical response to stress ( Hung et al ,. 2009 ). Both methods are applicable to metals, non-metals, and composite materials for detection of damage and flaws and can be used in a complementary fashion to improve detection capability and accuracy.
Infrared thermography is based on the principle that subsurface anomalies in a material result in localized differences in surface temperature caused by different rates of heat transfer at the defect zones. Thermography senses the emission of thermal radiation from the material surface and produces a visual image from this thermal signal which can be related to the size of an internal defect. Most infrared thermography applications use a thermographic camera in conjunction with an infrared-sensitive detector which images the heat radiation contrasts. Thermographic imaging may involve active or passive sources such as a flash tube or solar radiation. Active thermography can be further divided into four groups based on the excitation techniques: transient pulse thermography, step heating (long pulse thermography), periodic heating (lock-in) thermography, and thermal mechanical vibration thermography (vibrothermography) ( Hung et al ,. 2009 ). Use of active thermography improves the applicability and accuracy of the technique, enabling quantitative information regarding subsurface defects. Figure 5.12 shows active thermographic imaging of FRP-bonded concrete for detection of debonding. The obtained images show the potential of the method in detection and sizing of the defects behind single or multiple layers of FRP reinforcement ( Cantini et al ,. 2012 ).
5.12 . Infrared thermographic imaging of CFRP-bonded concrete specimen for detection of delamination.
Shearography is an interferometric imaging technique that directly mea-sures the selected first derivatives of specific surface displacement components (components of surface strains) using coherent laser illumination and a charge-coupled device (CCD) camera for recording ( Hung et al ,. 2009; Lai et al ,. 2009 ).The technique has been used for detection of delaminations, residual stresses, vibration modes, and leakage detection and has gained industrial acceptance as a practical and reliable NDT method. Non-destructive testing using digital shearography involves recording of two states of an object, before and after the application of certain stresses using thermal, acoustic, or pressure loading.
Both IRT and DISH were successfully applied to detection of debonding in FRP-bonded concrete in several studies with up to 90% accuracy in determining the sizes of artificial defects ( Hung et al ,. 2009; Lai et al ,. 2009; Taillade et al ,. 2011; Cantini et al ,. 2012 ). Complementary use of these two methods in field applications has the potential to provide effective and cost-efficient non-destructive evaluation of bonded FRP applications in structural engineering.
In Hybrid Microcircuit Technology Handbook (Second Edition) , 1998
IR thermography is more useful than IR microscopy in the design and testing of hybrid microcircuits, IR thermography provides a color temperature profile of the circuit while the circuit is under power. The scan can be compared with the scan of a failed hybrid to isolate a faulty device or design. In the initial design stage, thermal profiles may be used to position and arrange devices so that heat can be more evenly distributed and dissipated. Revised layouts can be evaluated and design changes incorporated before hybrids are committed to production.
Thermography involves the generation of thermal images of emitted blackbody radiation from hybrids, Very few objects are black bodies and a correction factor (emissivity) must be applied to the blackbody equation to get a true temperature. With instrumentation presently available, the detected IR energy is displayed as a digital temperature-profile map of the circuit. This image is presented on the screen of a color monitor, with the various colors (up to 256) indicating temperature differences of 0.1°C. The true temperature of a circuit must take into account the emissivity of the sample. It is possible, with today's equipment, to correct for the differences of emissivity of the various elements in a hybrid. This is accomplished by scanning a nonoperating hybrid and storing the IR energy. This is stored in the equipment, and each pixel in the raster can be corrected when a scan of an operating hybrid is input, giving a true temperature picture of the hybrid. Figure 13 is a photo of a thermography system manufactured by UTI Instruments.
Figure 13 .
Active thermography for evaluation of reinforced concrete structures
C. Maierhofer , ... J. Schlichting , in Non-Destructive Evaluation of Reinforced Concrete Structures: Non-Destructive Testing Methods , 2010
Infrared (IR) thermography, which encompasses the determination of the surface temperature of an object using an IR camera, is an imaging technology that is contactless and completely non-destructive. Its applications are classified into passive and active methods. By using passive thermography, differences in emissivity and, if a temperature gradient is present, differences in temperatures can be related to subsurface structures. If additional energy is induced into the structure by heating or cooling, the procedure is called active thermography. Active thermography methods enable structural investigations of building elements taking into account many different testing problems. In this chapter, the physical background, the equipment used, and the influences from environment and material properties are discussed. Several results of applications concerning the detection of subsurface defects are presented.
Corrosion under insulation
Neil Wilds , in Trends in Oil and Gas Corrosion Research and Technologies , 2017
17.5.2 Infrared thermography
IR thermography can be effectively used to identify wet insulation in pipelines and is much more effective than traditional moisture density gauges in addition to being a much faster technique. An added benefit is that pipelines can be scanned with this technique from a distance, negating the need for costly and time-consuming construction of scaffolding. Inspections can be carried out on either heat-traced or nontraced insulated pipelines. The technique is dependent on the fact that wet insulation retains heat longer than dry insulation, and therefore carrying out the inspection after sunset or when the pipelines are shaded will allow the inspector to distinguish between hot wet lines and cooler dry lines. Because the temperature between wet insulation and dry insulation is not large, it is recommended as best practice to use a small temperature span to increase the sensitivity of the technique.
Natural fiber-reinforced polymer composites
Deepak Verma , Kheng Lim Goh , in Biomass, Biopolymer-Based Materials, and Bioenergy , 2019
22.214.171.124 Infrared thermography
Infrared thermography is another advanced NDT method that uses electromagnetic radiation over the infrared spectrum at wavelengths of around 700 nm to 1 mm. As the name implies, this bandwidth is felt by the human body as “warmth,” and the method has found very good application in industries for the detection of overheating in electrical circuits and in pipes of petrochemical processing plants. Such evaluations can be performed indifferently, as the IR radiation is generated by the source in its standard operating state. However, inadequate heat is dissipated by the internal structure of a composite which permits measurements to be performed on composite structures, and an active heating source is needed to carry out an accurate investigation of these structures. The major limitation of thermography is its limited utilization related to thick structures. The physical limitation of heat transfer in most of the structures resulted in a quick decrease in sensitivity of components  .
- Word / Article
- Starts with
- Free toolbar & extensions
- Word of the Day
- Free content
I nfrared is the electromagnetic radiation outside the color spectrum range of visibility, at the lower end and next to the red. Infrared film has been sensitized to this radiation. Infrared film is commonly used at séances where there is total darkness, or where the light is too dim to allow regular photography. In this way it is possible to photograph things which cannot be seen under many séance conditions (e.g. ectoplasm, spirit forms).
- active infrared detection system
- Borisevich, Nikolai
- Borisevich, Nikolai Aleksandrovich
- cooled infrared detector
- cryogenic cooling
- Curing Oven
- earth satellite thematic sensing
- effective terrestrial radiation
- electromagnetic radiation
- electronic countermeasures
- far infrared
- far-infrared radiation
- FLIR imager
- forward-looking infrared
- forward-looking infrared imager
- framing imager
- InfoWord Office
- infracerebral gland
- Infrachromatic Materials
- infradyne receiver
- infraglenoid tubercle
- infragravity wave
- infralateral tangent arcs
- infralow frequency
- infrared absorption
- Infrared Aerial Surveying
- infrared array
- infrared astronomy
- infrared background radiation
- infrared beacon
- infrared binoculars
- infrared bolometer
- infrared brazing
- infrared catastrophe
- infrared cirrus
- infrared communications set
- Infrared Data Association
- infrared detector
- infrared detectors
- Infrared Direction Finding
- infrared dome
- infrared drying
- infrared dwarf
- infrared emission
- infrared emittance
- infrared film
- infrared filter
- infrared galaxy
- infrared guidance
- infraorbitomeatal line
- infraorbitomeatal plane
- infrapalpebral sulcus
- Infrapatellar Branch of Saphenous Nerve
- Infrapatellar bursitis
- infrapatellar fat body
- infrapatellar fat pad
- infrapatellar fat-pad
- infrapatellar synovial fold
- infrared absorption spectroscopy
- Infrared Active Homing
- Infrared Aiming Light
- Infrared Airborne Radar
- Infrared All-Aspect
- Infrared Analysis Modeling & Measurements Program
- Infrared and Raman Discussion Group
- Infrared and Raman Spectroscopy Literature Database Bibliography
- Infrared and Raman Users' Group
- Infrared and Visible Optical Sensors
- Infrared Anomalous Emitter
- Infrared Area Correlator
- Infrared Array Camera
- Infrared Astronomical Satellite
- Infrared astronomy
- Infrared Astronomy Satellite
- Infrared Atmospheric Signature Prediction Model
- Facebook Share
- Mobile and wireless network technology
infrared radiation (IR)
- Jessica Scarpati
Infrared radiation (IR), sometimes referred to simply as infrared, is a region of the electromagnetic radiation spectrum where wavelengths range from about 700 nanometers (nm) to 1 millimeter (mm). Infrared waves are longer than those of visible light, but shorter than those of radio waves. Correspondingly, the frequencies of IR are higher than those of microwaves, but lower than those of visible light, ranging from about 300 Ghz to 400 THz.
Infrared light is invisible to the human eye, although longer infrared waves can be sensed as heat. It does, however, share some characteristics with visible light -- namely, infrared light can be focused, reflected and polarized .
Wavelength and frequency
Infrared can be subdivided into multiple spectral regions, or bands, based on wavelength; however, there is no uniform definition of each band's exact boundaries. Infrared is commonly separated into near-, mid- and far-infrared. It can also be divided into five categories: near-, short-wavelength, mid-, long-wavelength and far-infrared.
The near-IR band contains the range of wavelengths closest to the red end of the visible light spectrum. It is generally considered to consist of wavelengths measuring from 750 nm to 1,300 nm -- or 0.75 to 1.3 microns. Its frequency ranges from about 215 THz to 400 THz. This group consists of the longest wavelengths and shortest frequencies, and it produces the least heat.
The intermediate IR band , also called the mid-IR band, covers wavelengths ranging from 1,300 nm to 3,000 nm -- or 1.3 to 3 microns. Frequencies range from 20 THz to 215 THz.
Wavelengths in the far-IR band, which are closest to microwaves, extend from 3,000 nm to 1 mm -- or 3 to 1,000 microns. Frequencies range from 0.3 THz to 20 THz. This group consists of the shortest wavelengths and longest frequencies, and it produces the most heat.
Infrared radiation uses
Infrared is used in a variety of applications. Among the most well-known are heat sensors, thermal imaging and night vision equipment.
In communications and networking, infrared light is used in wired and wireless operations. Remote controls use near-infrared light, transmitted with light-emitting diodes (LEDs), to send focused signals to home-entertainment devices, such as televisions. Infrared light is also used in fiber optic cables to transmit data.
In addition, infrared is used extensively in astronomy to observe objects in space that can't be detected in whole or part by the human eye, including molecular clouds, stars, planets and active galaxies.
History of infrared radiation technology
Infrared was discovered by British astronomer Sir William Herschel in 1800. Herschel knew sunlight could be separated into separate components, a step accomplished by refracting the light through a glass prism. He then measured the temperatures of the different colors that were created. He found the temperature increased as the colors progressed from violet, blue, green, yellow, orange and red light. Herschel then went a step further, measuring the temperature in the portion beyond the red area. There, in the infrared area, he found the temperature to be the highest of all.
Continue Reading About infrared radiation (IR)
- What is an electromagnetic field? Read this
- Understand electromagnetic interference
- Learn how infrared light is transforming collaboration
- The latest in visible light communications
Dig deeper on mobile and wireless network technology.
dense wavelength-division multiplexing (DWDM)
More organizations are adopting ESG initiatives, and UC vendors have begun to offer new programs and capabilities in response. ...
The tech giant's $10 billion investment in OpenAI brings AI-supported updates to its basic Teams offering, on top of features ...
The new platform moves to the modern cloud infrastructure and offers a streamlined inbox, an AI-supported writing tool and ...
Configuration profiles make it easier to manage BYOD iPhones, but they're also associated with malware. Mobile security policies ...
User Enrollment creates a management profile for BYOD iPhones, but IT must remove that data in cases such as device loss or theft...
User Enrollment in iOS can separate work and personal data on BYOD devices. IT teams should learn how to enable it in Microsoft ...
Linux admins can use Cockpit to view Linux logs, monitor server performance and manage users. Use the tool to help admins manage ...
Hyperscale data centers can hold thousands of servers and process much more data than an enterprise facility. However, they can ...
Organizations that build 5G data centers may need to upgrade their infrastructure. These 5G providers offer products like virtual...
Software and services companies are adding personnel and expanding their offerings, as venture funds invest in tech startups with...
Businesses working with aging network architectures could use a tech refresh. While the easing of equipment backlogs works in ...
Industry studies underscore businesses' continuing struggle to obtain cloud computing benefits. A greater focus on strategy, ...
- Australia edition
- International edition
How to write a science news story based on a research paper
Most journalists want to break exclusives, but a lot of what science journalists write is neccesarily based on the latest research findings, published for all the world to see in academic journals. Exclusive they are not. Nevertheless, it is perfectly possible to write a great news story that takes the contents of a research paper as its starting point. Here are some guidelines.
1. Find a good paper
Thousands of scientific papers are published each week. The majority will not make good news stories. Look for work that is entertaining, fascinating, important or controversial. Ask yourself: will anyone care? Be brutal about this. Move on if the answer is no.
You cannot cover a paper properly without reading it. The abstract will give the barest essentials. You need to read the introduction for context, the discussion and conclusions for take-home messages. Check the methods. Was the experiment well designed? Was it large enough to draw conclusions from? Find weaknesses and flaws. You will probably need help to work out how fatal they are. Spend time on the results. Have the authors omitted key data? Look at odds ratios, error bars, fitted curves and statistical significances. Are the results robust? Do they back up the scientists' conclusions? Remember: nematodes, fruit flies and mice are not humans, and what happens in a Petri dish won't neccesarily happen in a person. Read the supplementary material too. You will find gems.
3. Vested interests
Check for conflicts of interest. These should be declared at the end of the paper, but make your own checks too. Plenty of scientists have financial links with companies. The reader might want to know about them.
4. Get context
Science builds on science. Know the previous studies that matter so you can paint a fuller picture. If your story is about chimps in Guinea using cleavers and anvils, you might mention the different tools that chimps in the Republic of Congo use for termite fishing.
5. Interview the authors
Write from the paper alone and your news story will be dull. Interviews with authors will give you the colour to tell a story. How did the face transplant patient react when they looked in the mirror? What possessed the authors to study spiders on cocaine? How did it feel to unearth the remnants of an ancient hearth, knowing a Neanderthal sat in the same spot 40,000 years ago?
Get them to explain their results and justify their conclusions. What do the results mean in plain English? What do they not mean? Ask your questions in simple language to get answers you can quote. Run phrases you might use past the authors, so they can warn you of howlers. Do not ask multi-part questions: you will not get full answers.
Remember that papers can take months to appear in journals, so find out how the work has moved on since the work was submitted.
Think about whom you want to interview. First authors are generally the graduate students or postdocs who did all the work. Last authors are often senior scientists. On a good day, a senior author will give you the clearest explanation, the perfect quote, and the richest context. On a bad day, they will have no recollection of the paper their name appears on.
6. Get other scientists' opinions
Send the paper to a handful of experts to check. You will find people in the paper's references, or on Google Scholar . Chat about the paper on the phone. Some scientists will email you thick paragraphs of reaction. You might salvage a sentence or two, but email makes for clunky quotes: people do not speak the way they write. Ask your expert if the work looks sound or flakey. What does it add? What is the striking result? Will it be controversial? What fresh questions does it raise? Comments from other scientists will always improve your story. They will also save you from writing a story you wish you had never touched.
7. Find the top line
You've read the paper, interviewed the authors and discussed the work with other experts. Now you need to find the top line. One option is what drew you to the paper in the first place. But there will be others. Go over your interviews. What stood out as most fascinating, alarming, amusing, or important? Does it make for a stronger angle? Bear in mind that the story you should tell your readers might not be the story the authors want you to tell your readers.
8. Remember whom you are writing for
The reader may be clever and curious about the world. But do not assume they are a scientist, or that they have time to read boring, unimportant or incoherent stories. Make your story clear and informed. Science is hard enough, so use simple words. Do not patronise the reader. Respect them and be honest. Make them glad they read you.
9. Be right
Don't write a story that is wrong. This is harder than it sounds. Most scientific papers are wrong, thanks to poor study designs, author biases, small sample sizes and other problems. So don't make things worse by introducing errors of your own. Check everything. Mistakes leave readers confused and misinformed. They will undermine your credibility too. Call a shrew a rodent and your soricid story is ruined.
10. Write well
Reporters often pick the same papers to cover. Why should anyone read you? You must have something to add. Make an effort to get the details that readers want to know. And learn how to write well. Find a clear path through the story and build one paragraph after another in logical order. Stick to one idea for each paragraph. Read Strunk and White until you can hear them tutting as your type. Even the shortest stories can be memorable in the hands of a good writer.
Speak to the authors and get independent comment from scientists in the same field. Get your facts straight.
Patronise your readers. Mistake fruit flies, mice or Petri dishes for people.
Click here to enter the Wellcome Trust Science Writing Prize , in association with the Guardian and the Observer. The closing date for entries is 11 May 2014
Coming up in this series:
- Science writing prize
- Secrets of good science writing
How to avoid common mistakes in science writing
Black death skeletons reveal pitiful life of 14th-century Londoners
Dwarf planet discovery hints at a hidden Super Earth in solar system
How to create a successful science blog
How to write a science feature
Talk to me! Top tips for conducting interviews with scientists
Children's hyperactivity 'is not a real disease', says US expert
Kidnapped stars, Martian frost and the Rotten Egg Nebula – in pictures
Science Weekly Science Weekly podcast: how to rebuild our world from scratch
Communication Using Infrared Technology
Infrared band of the electromagnet corresponds to 430THz to 300GHz and a wavelength of 980nm . The propagation of light waves in this band can be used for a communication system (for transmission and reception) of data. This communication can be between two portable devices or between a portable device and a fixed device.
There are two types of Infrared communication
- Point to Point : It requires a line of sight between the transmitter and a receiver. In other words the transmitter and the receiver should be pointed to each other and there shouldn’t be any obstacles between them. Example is the remote control communication.
- Diffuse Point : It doesn’t require any line of sight and the link between the transmitter and the receiver is maintained by reflecting or bouncing of the transmitted signal by surfaces like ceilings, roof, etc. Example is the wireless LAN communication system
Advantages of IR communication:
- Security: Infrared communication has high directionality and can identify the source as different sources emit radiation of different frequencies and thus the risk of information being diffused is eliminated.
- Safety: Infrared radiation is not harmful to human beings. Hence infrared communication can be used at any place.
- High Speed data Communication: The data rate of Infrared communication is about 1Gbps and can be used for sending information like video signal.
IR Communication basics:
The transmitter of an IR LED inside its circuit, which emits infrared light for every electric pulse given to it. This pulse is generated as a button on the remote is pressed, thus completing the circuit, providing bias to the LED.
The LED on being biased emits light of the wavelength of 940nm as a series of pulses, corresponding to the button pressed. However since along with the IR LED many other sources of infrared light such as us human beings, light bulbs, sun, etc, the transmitted information can be interfered. A solution to this problem is by modulation. The transmitted signal is modulated using a carrier frequency of 38 KHz (or any other frequency between 36 to 46 KHz). The IR LED is made to oscillate at this frequency for the time duration of the pulse. The information or the light signals are pulse width modulated and are contained in the 38 KHz frequency.
The receiver consists of a photodetector which develops an output electrical signal as light is incident on it. The output of the detector is filtered using a narrow band filter that discards all the frequencies below or above the carrier frequency (38 KHz in this case). The filtered output is then given to the suitable device like a Microcontroller or a Microprocessor which controls devices like a PC or a Robot. The output from the filters can also be connected to the Oscilloscope to read the pulses.
Parts of IR communication system:
IR Transmittor- IR Sensor
The sensors could be utilized as a part of measuring the radiation temperature without any contact. For different radiation temperature ranges various filters are available. An infrared (IR) sensor is an electronic device that radiates or locates infrared radiation to sense some part of its surroundings. They are undetectable to human eyes.
An infrared sensor could be considered a Polaroid that briefly recalls how an area’s infrared radiation shows up. It is very regular for an infrared sensor to be coordinated into movement indicators like those utilized as a feature of private or business security systems. An IR sensor is shown in figure; basically it has two terminals positive and negative. These sensors are undetectable to human eyes. They can measure the heat of an object and also identify movement. The region wavelength roughly from 0.75µm to 1000 µm is the IR region. The wavelength region of 0.75µm to 3 µm is called close infrared, the region from 3 µm to 6 µm is called mid infrared and the region higher than 6 µm is called far infrared. IR sensors emits at a frequency of 38 KHz.
Features of IR Sensor:
- Input voltage: 5VDC
- Sensing Range: 5cm
- Output signal: analog voltage
- Emitting element: Infrared LED
Example interfacing circuit of IR diode and photodiode
IR sensors mostly used in radiation thermometer, gas analyzers, industrial applications, IR imaging devices, tracking, and human body detection, communication and health hazards
Here is a brief description of IR & Photo diode sensing switch:
An IR diode is connected through a resistance to the dc supply. A photo diode is connected in reverse biased condition through a potential divider of a 10k variable resistance and 1k in series to the base of the transistor. While the IR rays fall on the reverse biased photo diode it conducts that causes a voltage at the base of the transistor.
The transistor then works like a switch while the collector goes to ground. Once the IR rays are obstructed the driving voltage is not available to the transistor thus its collector goes high. This low to high logic can be used for the microcontroller input for any action as per the program.
IR Receiver/TSOP Sensor – Features & Specifications
TSOP is the standard IR remote control receiver series, supporting all major transmission codes. This is capable of receiving infrared radiation modulated at 38 kHz. IR sensors we have seen up to now working just for little short distance up to 6 cm. TSOP is sensitive to a specific frequency so its range is better contrast with ordinary photo diode. We can alter it up to 15 cm.
TSOP acts like as a receiver. It has three pins GND, Vs and OUT. GND is connected to common ground, Vs is connected to +5volts and OUT is connected to output pin. TSOP sensor has an inbuilt control circuit for amplifying the coded pulses from the IR transmitter. These are commonly used in TV remote receivers. As I said above TSOP sensors sense only a particular frequency.
- The preamplifier and photo detector both are in single package
- Internal filter for PCM frequency
- Improved shielding against electrical field disturbance
- TTL and CMOS compatibility
- Output active low
- Low power consumption
- High immunity against ambient light
- Continuous data transmission possible
- Supply Voltage is –0.3-6.0 V
- Supply Current is 5 mA
- Output Voltage is –0.3-6.0 V
- Output Current is 5 mA
- Storage Temperature Range is –25-+85 °C
- Operating Temperature Range is –25-+85°C
The testing of TSOP is very simple. These are commonly used in TV remote receivers. TSOP consists of a PIN diode and pre-amplifier internally. Connect TSOP sensor as shown in circuit. A LED is connected through a resistance from the supply to output.
And then when we press the button of T.V. Remote control in front of the TSOP sensor, if LED starts blinking then our TSOP sensor and its connection is correct. The point when the output of TSOP is low i.e. at the time it appropriates IR signal from a source, with a centre frequency of 38 kHz, its output goes low.
TSOP sensor is used in our daily use TV, VCD, music system’s remote control. Where IR rays are transmitted by pushing a button on remote which are received by TSOP receiver inside the equipment.
- IR communication principle by sbprojects
Share This Post:
Comments are closed.
- Free Circuits
- Interview Questions
- ECE Projects
- EEE Projects
- Project Ideas
- Resistor Color Code Calculator
- Ohms Law Calculator
- Circuit Design
How to write a news article
Writing a news story or newspaper article for school assignment can be stressful to many students. Unless you’re a Journalism major , this is the first time most students have ever written a news article or paper of any kind. If you need to know how to write a newspaper article, read on for great tips, examples, structure, and outline.
When writing your newspaper article, make sure it has several components.
- The first component should be an introductory paragraph where the reader learns who, what, when and where.
- The second component is body paragraphs . These will feature quotes from people such as the reporter or eyewitnesses to the event.
- A conclusion. Conclude with a closing paragraph that references all information in your article.
You may want to have a “by line” at the beginning of your article where you state who wrote the article. The by line could also include your position or role in a news event or a quote from a person that was interviewed for the article.
How to write a feature article
A good news article can be one of the most challenging types of writing for someone to do well, but also one of the most rewarding when it goes over well with an audience. In fact, many journalists will tell you that they find this type of work very difficult and stressful, since there are so many guidelines and details that need to be followed to produce a great piece. Before you attempt a story, it’s a good idea to learn what makes writing a news article work well.
Let us review the process of writing a newspaper article for school.
How to Write a News Story – 10 Steps
Here are 7 steps in writing a good news story for school or for your english or journalism class:
Choose a current, newsworthy event or topic to write about.
Conduct timely, in-person interviews with witnesses.
- Establish the “Four Main Ws”
Plan your article
Create an outline, write your first draft, insert quotations, research additional facts and figures, read your article out loud before publication, polish up your article for publishing.
Each of the step is discussed below:
First of all, you will need to choose a good topic for your article. Try to find something that is currently happening and important in the world. If you’re writing an article for school, it’s best if you pick something that interests you personally so that you can do some research about it and make your opinion known in the article.
How to find a news topic to write about:
- Look for popular news stories on the internet at websites like CNN News or BBC News .
- Watch the TV to see if any current topics are being covered.
- Ask your parents what they’ve been watching on TV and why it’s important.
- Read the newspaper to see what is trending.
- Read the flyers and posters around your house and school for inspiration!
Let’s say you want to write about the 2016 U.S elections and who you think will win the presidency. This is a good topic because politics are always ongoing and there is never a lack of topics for debates. You can look on news websites or search on social media websites such as Facebook to find new, incoming events that might be newsworthy. Or, you can also just stay up to date on the news by watching your local channel or reading the newspaper.
Once you have a identified a news topic, it’s time to get started!
This is a really important part of how to write a news story for your class or for your school newspaper. You need to get information from people who were actually there so that you can write about their experiences. Some of these people may include eyewitnesses or police officers who arrived at the scene of an accident. You should also interview people who have been affected by the issue or event that you are writing about.
For example, if you were writing a story on bullying in your school, you would want to talk with bullies and victims of bullying as well as teachers and staff members.
You should ask each person the same set of questions so that their answers can be compared later. You can also make it easier to compare answers by numbering each question in order.
For example, if you are interviewing three students about their experiences with bullying at your school, you could ask them questions 1-3 for the first student and 4-6 for the second student all while recording their responses or having another person take notes.
- What is your name?
- How long have you been bullied for?
- Have you ever seen another person being bullied at school?
Make sure to give each person a chance to tell you what they think about the issue, solution, or event that you are writing about. This means that you will have to ask them questions that they might not have felt comfortable answering on their own, such as “What do you think should be done to stop bullying?”
Sometimes people may not want to talk with you, but this doesn’t necessarily mean that there is something wrong with what they have to say.
Establish the “Five Main Ws”
This is also called the Five Ws and One H. You should always answer Who, What, When, Where, Why and How when writing a newspaper article. The sixth question that journalists ask is “How much?” but in some cases, this can be included in the “What” question.
- Who: Who is the story about?
- What: What happened?
- When: When did it happen?
- Where: Where did it take place?
- Why: Why did this happen?
Before you start writing about an event or story, make sure that you understand what is happening and how it happened. You need to figure out the who, what, when, where and why of the story. You can do this by conducting good, in-person interviews with witnesses, experts and eyewitnesses of the event you are writing about.
List the important facts about your story. What makes this newsworthy to readers? Do you have any breaking details or hints of drama in your piece?
List possible interviewees for your article. You’ll want to include different people who could provide different perspectives on the topic if at all possible. For example, if you are writing an article about a new community centre opening in your neighbourhood, you will want to include the director of the community centre and other people who live in your area.
A good outline should be a short paragraph or a number of points that describes what you plan on writing about and how you intend to structure it. You should include information such as the topic, who you will be interviewing and what your article will include.
Now it’s time to put everything you’ve learned into practice! Make sure that your article flows well and is free of spelling or grammar errors before moving on to the next step. The most important thing here is to make sure you don’t miss anything, so make sure to read over your story a few times before proceeding further.
Once you have your facts straight about your article topic, it’s time to include quotes from people that were actually there and saw what happened. Try to use quotes that best describe the event in order to paint a vivid picture.
This is where you will include any additional information that you have found about your article topic during your research. You can also use this space to talk about various statistics related to the topic, for example how many people died because of the cause of your story or what cities are most affected by the event or issue.
This is an important part of how to write a news story because if you read it out loud, you can catch any mistakes that may have slipped through in your writing process. No matter how great the rest of your article was written, if there are typos or grammatical errors, it will probably be rejected by the news website that you’re submitting your article to.
Get someone else to review your article. This could be a co-worker, a proofreading service , or a friend that you feel would have useful input into the story and how it is presented. Let them know what kind of feedback you are looking for and that you would appreciate their input. You can also request feedback from your teacher or professor if you are submitting the article for class.
Check over your article once more to make sure it is free of errors before publishing it.
General tips for writing an “A” grade newspaper article:
- Avoid flowery language, long sentences and big words…write as you would speak to someone
- Include quotes from eyewitnesses and people who are part of the story
- Proofread your article several times or have a friend check it for grammar or spelling mistakes
- Double check that you have spelled names correctly in your article. If possible, use a name in a quote to ensure you spell it right. If not, call the person and ask them to spell their name for you.
- Include a relevant picture of the people involved, not just the location (a picture of the car that was stolen or even of a person with a quote about how they feel.)
- Timelines are important in news writing – include them!
Create a news story based on this scenario: The town where you live has recently found a new source of water. People have been asking where the water came from, so you decided to investigate. You discovered that after years without rain or snow, the town’s reservoirs dried up and were not able to provide enough fresh water for people to drink. After a few dry wells, residents began digging their own wells until a nearby farmer hit water.
Do you need help writing a news article assignment? Click here to ask for news story assignment writing help by professional journalists and college paper writing help instructors.
What are your thoughts on how to write a news article for school assignment?
Types of statistical analysis
Wilcoxon signed rank test, related guides.
Need Academic Writing Help?
Hire a Writer Now
Infrared (IR) Spectroscopy- Definition, Principle, Parts, Uses
Table of Contents
What is Infrared (IR) Spectroscopy?
Infrared (IR) spectroscopy or vibrational spectroscopy is an analytical technique that takes advantage of the vibrational transitions of a molecule .
It is one of the most common and widely used spectroscopic techniques employed mainly by inorganic and organic chemists due to its usefulness in determining the structures of compounds and identifying them.
The method or technique of infrared spectroscopy is conducted with an instrument called an infrared spectrometer (or spectrophotometer ) to produce an infrared spectrum.
Image Source: BYJUS .
Principle of Infrared (IR) Spectroscopy
- Infrared Spectroscopy is the analysis of infrared light interacting with a molecule.
- The portion of the infrared region most useful for analysis of organic compounds have a wavelength range from 2,500 to 16,000 nm, with a corresponding frequency range from 1.9*1013 to 1.2*1014 Hz.
- Photon energies associated with this part of the infrared (from 1 to 15 kcal/mole) are not large enough to excite electrons, but may induce vibrational excitation of covalently bonded atoms and groups.
- It is known that in addition to the facile rotation of groups about single bonds, molecules experience a wide variety of vibrational motions, characteristic of their component atoms.
- Consequently, virtually all organic compounds will absorb infrared radiation that corresponds in energy to these vibrations.
- Infrared spectrometers, similar in principle to other spectrometer, permit chemists to obtain absorption spectra of compounds that are a unique reflection of their molecular structure.
- The fundamental measurement obtained in infrared spectroscopy is an infrared spectrum, which is a plot of measured infrared intensity versus wavelength (or frequency) of light.
- IR Spectroscopy measures the vibrations of atoms, and based on this it is possible to determine the functional groups.
- Generally, stronger bonds and light atoms will vibrate at a high stretching frequency (wavenumber).
Instrumentation of Infrared (IR) Spectroscopy
The main parts of the IR spectrometer are as follows:
- Radiation source
- Sample cells and sampling of substances
A. IR radiation sources
IR instruments require a source of radiant energy which emits IR radiation which must be steady, intense enough for detection, and extend over the desired wavelength.
Various sources of IR radiations are as follows.
- Nernst glower
- Incandescent lamp
- Mercury arc
- Tungsten lamp
- Glober source
- Nichrome wire
B. Sample cells and sampling of substances
IR spectroscopy has been used for the characterization of solid, liquid, or gas samples.
i. Solid – Various techniques are used for preparing solid samples such as pressed pellet technique, solid run in solution, solid films, mull technique, etc.
ii. Liquid – Samples can be held using a liquid sample cell made of alkali halides. Aqueous solvents cannot be used as they will dissolve alkali halides. Only organic solvents like chloroform can be used.
iii. Gas– Sampling of gas is similar to the sampling of liquids.
- Various types of monochromators are prism, gratings and filters.
- Prisms are made of Potassium bromide, Sodium chloride or Caesium iodide.
- Filters are made up of Lithium Fluoride and Diffraction gratings are made up of alkali halides.
- Detectors are used to measure the intensity of unabsorbed infrared radiation.
- Detectors like thermocouples, Bolometers, thermisters, Golay cell, and pyro-electric detectors are used.
- Recorders are used to record the IR spectrum.
Subscribe us to receive latest notes.
Applications of Infrared (IR) Spectroscopy
It has been of great significance to scientific researchers in many fields such as:
- Protein characterization
- Nanoscale semiconductor analysis and
- Space exploration.
- Analysis of gaseous, liquid or solid samples
- Identification of compounds
- Quantitative analysis
- Information regarding functional groups of molecules and constitution of molecules can be deduced from IR spectrum
- To know about interaction among molecules
- 22 Types of Spectroscopy with Definition, Principle, Steps, Uses
- Bacteria- Definition, Structure, Shapes, Sizes, Classification
- Light Microscope- Definition, Principle, Types, Parts, Labeled Diagram, Magnification
- 14 Types of Chromatography (Definition, Principle, Steps, Uses)
- Respiratory Microbiota- Normal Flora of Respiratory Tract
- https://www.pharmatutor.org/pharma-analysis/analytical-aspects-of-infra-red spectroscopy-ir/instrumentation-of-ir-spectrophotometry
4 thoughts on “Infrared (IR) Spectroscopy- Definition, Principle, Parts, Uses”
Is it possible to obtain permission to use the diagram of the infrared spectrophotomer on
in a textbook entitled Organic Chemistry, an Acid-Base Approach, 3rd edition, to be published by Taylor and Francis in 2022.
Michael B. Smith (author) at [email protected]
Hello Michael B. Smith, Thank you so much for your comment. The original source of the image is https://byjus.com/chemistry/infrared-spectroscopy/ .
Nice work very informative post keep doing like this..
Leave a Comment Cancel reply
Save my name, email, and website in this browser for the next time I comment.
This site uses Akismet to reduce spam. Learn how your comment data is processed .
- Electromagnetic Waves
- Infrared Radiation
Infrared Radiation - Electromagnetic Waves
What is Infrared Radiation?
Infrared radiation (IR), sometimes known as infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of visible light. Hence, it is undetectable by the human eye, although IR of wavelengths up to 1050 nanometers (nm) from specially pulsed lasers can be seen by humans under certain conditions. Infrared light extends from the suggested red edge of the visible spectrum at 700 nanometers to 1 millimetre. Most of the thermal radiation emitted by objects near room temperature is infrared. As with all EMR , IR carries radiant energy and behaves both like a wave and like its quantum particle, the photon. Depending on the wavelength and frequency, infrared is commonly divided into five categories as near-wavelength, short-wavelength, mid-wavelength, long-wavelength and far-infrared .
Characteristics of Infrared Radiation
- Infrared radiations is also referred to as heat or thermal waves or electromagnetic waves . This is because they have a heat-inducing property. Sometimes infrared rays are used in applications where heat production is required, like in infrared heaters or for therapeutic purposes where a patient requires physical therapy.
- Sometimes infrared rays are classified as near-infrared and far-infrared.
- Near-infrared rays are used in electronic applications like TV remote sensors and photography. Their applications can be similar to visible light applications since their wavelength ranges are close.
- Far infrared rays are more thermal. Anything generating heat gives out far-infrared radiation. Even the human body at 37°C gives off infrared radiations of around 800 nm wavelength.
How was Infrared Radiation Discovered?
The wavelength of Infrared Radiation
We already know that the wavelength of infrared radiation is between 700 nm to 1 mm, which is between the red limit of the visible spectrum. But the following is the classification of bands based on the spectral range 1µm and 50µm:
- 1µm to 3µm, which is known as Band I or Short Wave Infrared
- 3µm to 5µm, which is known as the Band II or Middle Wave Infrared
- 8µm to 14µm, which is known as the Band III or Long Wave Infrared
Characteristics of Regions of Infrared
Properties of infrared waves.
Much of the energy from the sun reaches the Earth in the form of infrared radiation. The balance between absorbed and emitted infrared radiation has a critical effect on the Earth’s climate. Below, we have listed the properties of Infrared waves.
According to Serway’s College Physics, an infrared wave is said to be a transverse wave, i.e., the displacement of the wave is at the right angle to the direction of the wave propagation.
The wavelengths of infrared waves are unique and are usually measured in microns. A micron is defined as one millionth of a metre. The shortest wavelength of an infrared wave is about 0.7 microns. The longest wavelength of an infrared wave is 350 microns. According to studies, the upper limit of any infrared wave is 1000 microns.
The speed at which infrared waves travel is 299,792,458 m.s -1 .
Particle or Wave?
According to quantum theory, infrared waves can exist as either a wave or a particle at the same time.
Absorption and Reflection
The absorption and reflection of infrared waves depend on the nature of the substance that the waves are made to strike. Materials such as ozone, carbon dioxide, and water vapour absorb infrared radiation. Snow and aluminium foil are materials that reflect infrared radiation.
Refraction and Interference
Infrared waves exhibit the property of refraction, making the waves experience a slight change in direction when the wave passes from one medium to another. Refraction properties of infrared waves can be noticed in the earth’s atmosphere. When two infrared waves with the same wavelength meet each other, they will interfere with one another.
Infrared radiation can be the source of heat as they have thermal properties . When infrared radiation strikes the oxygen or nitrogen molecules, it makes the molecules move faster as they gain more energy. So it can be concluded that infrared radiation makes materials hotter and can be used as a heat source.
Where do we use Infrared Rays?
We make use of infrared rays in the following:
- Communications: Infrared lasers are used for free-space optical communications as these are relatively inexpensive. These also find applications in the areas that are densely populated.
- Spectroscopy: Infrared vibrational spectroscopy is used for identifying molecules by analysing their bonds as the molecule vibrates at different frequencies. The unit used to express the radiation is cm -1 .
- Astronomy: Optical components like mirrors, lenses and digital detectors are used to study the objects that are in space. These objects glow when they are exposed to radiated heat.
Applications of Infrared Waves
Following are the areas of use of infrared waves:
Two different industries use infrared radiation as a heat source, and they are:
- Medical uses: Infrared radiation finds application as a heating source. There are infrared saunas used to treat high blood pressure and rheumatoid arthritis. Infrared radiation is considered to be one of the safest methods of physiotherapy.
- Manufacturing industries: Industries which concentrate on manufacturing processes such as forming of plastics, curing of coatings, plastic welding, etc., use infrared heaters in place of contact heating and convection ovens.
Infrared rays are widely used for cosmetic applications such as treating skin injuries, smoothing wrinkles, reducing the occurrence of dandruff, blackheads, etc. Infrared rays are used because they can penetrate the skin up to 3-4 mm. They also warm the skin resulting in improved blood circulation and a continuous supply of oxygen and other nutrients to the skin.
Astronomers use optical devices such as mirrors, solid-state digital detectors, and lenses to study objects from space with the help of infrared waves. The images from these optical devices are obtained with the help of an infrared telescope.
Infrared rays are used for warming the skin and for relaxing the muscles. Infrared rays are preferred because of their penetration quality through the skin.
Infrared filters are used for capturing pictures in infrared photography. This imaging is done for objects that are placed in the near-infrared spectrum. Most digital cameras use infrared blockers making the near-infrared appear as a purple-white colour in the final image.
Data transmission with the help of infrared radiation is very common in short-range communication. For encoding the data, infrared light-emitting diodes are used, which emit infrared radiation and are focused into a narrow beam with the help of a plastic lens. At the receiver end, a photodiode is placed to convert infrared radiation into electric current.
Interesting Facts About Infrared Radiation
1.Who discovered infrared radiation?
Sir Frederick William Herschel discovered infrared radiation.
2. When was infrared discovered?
Infrared was discovered in the year 1800.
3. What does infrared mean?
The term infrared is a Latin word in which infra means below. Also, red is the colour with the longest wavelength in the visible spectrum. Therefore, it is known as infrared.
4. Name the infrared radiation measuring instrument.
Infrared radiation is measured using an instrument known as an infrared thermometer.
5. How does infrared radiation work?
The emission of infrared radiation from an object is possible when heated. The atoms and the molecules in the object start to vibrate, thereby radiating infrared in the form of heat. When the objects are not hot enough to produce visible light, they radiate infrared. Also, heat production is independent of the temperature of the surroundings.
Extended Reading List
Frequently Asked Questions on Infrared Radiation
List a few properties of infrared radiation..
Following are a few properties of infrared radiation:
- Infrared radiation, like all radiation, travels at a speed of 299,792,458 meters per second.
- Infrared light can exhibit both wave and particle nature at the same time.
- Depending on the nature of the material that infrared radiation strikes, it can either be absorbed or reflected.
- Infrared radiation increases the thermal energy in particles.
List a few medicinal effects of infrared radiation.
A few medicinal effects of infrared radiation are as follows:
- Used to reduce the inflammation of the throat, ear and nose
- Used as an aid in stress management
- Reduces pain arthritis
- It eases kidney function
How do we experience infrared radiation on a daily basis?
Infrared is a type of radiant energy that is invisible to the eyes; we can only feel it in the form of heat. All objects in the universe emit some level of IR radiation. Sun and fire are among the most obvious source of infrared radiation.
How to select infrared detectors?
Following are the guidelines that need to be followed when infrared detectors are selected:
- The temperature and wavelength of the object need to be measured.
- Photosensitivity and signal to noise need to be noted. Also, for signal noise reduction, the infrared detector must be cooled using either thermoelectric, mechanical, or cryogenic cooling.
- Depending on the application of the infrared detector, response speed and chopping frequency need to be recorded.
- When infrared detectors are used in the optical systems, the size and the geometry of the active area plays a vital role.
- Infrared detectors are available in various packages and these packages are metal can package and ceramic packages.
What is the classification of the infrared detector?
The infrared detector is classified into two:
- Thermal type: Heat supply to thermal type detector happens through the infrared energy and the photosensitivity is independent of the wavelength. The thermocouple is an example of a thermal type infrared detector.
- Quantum type: This can be either an intrinsic type or extrinsic type. The detection performance is higher when compared to the thermal type. Intrinsic type is further divided into two and they are photoconductive type and photovoltaic type. The photosensitivity of these detectors is dependent on the wavelength.
What are the characteristics of infrared radiation?
- Invisible to human eyes: This is considered to be one of the characteristics of infrared radiation and is also useful for security purposes. The drawback of the invisibility of infrared radiation to the human eye is that designing optical instruments becomes difficult.
- Small energy: The energy of infrared radiation is equal to the vibrational and rotational energy of the molecules. This characteristic is used in the identification of the molecules.
- Long-wavelength: The transmission becomes better as there is less scattering through the medium.
- Infrared radiation can be emitted from all kinds of objects.
Put your understanding of this concept to test by answering a few MCQs. Click ‘Start Quiz’ to begin!
Select the correct answer and click on the “Finish” button Check your score and answers at the end of the quiz
Visit BYJU’S for all Physics related queries and study materials
Your result is as below
Leave a Comment Cancel reply
Your Mobile number and Email id will not be published. Required fields are marked *
Request OTP on Voice Call
- Share Share
Register with BYJU'S & Download Free PDFs
What is IR Sensor : Circuit & Its Working
July 21, 2021 By WatElectronics
IR technology is used in a wide range of wireless applications which includes remote controls and sensing. The infrared part in the electromagnetic spectrum can be separated into three main regions: near IR, mid-IR & far IR. The wavelengths of these three regions vary based on the application. For the near IR region, the wavelength ranges from 700 nm- 1400 nm, the wavelength of the mid-IR region ranges from 1400 nm – 3000 nm & finally for the far IR region, the wavelength ranges from 3000 nm – 1 mm.
The near IR region is used on fiber optic & IR sensors , the mid-IR region is used for heat sensing and the far IR region is used in thermal imaging. The range of frequency for IR is maximum as compared to microwave and minimum than visible light. This article discusses an overview of the IR sensor and its working.
What is IR Sensor?
The IR sensor or infrared sensor is one kind of electronic component, used to detect specific characteristics in its surroundings through emitting or detecting IR radiation. These sensors can also be used to detect or measure the heat of a target and its motion . In many electronic devices, the IR sensor circuit is a very essential module. This kind of sensor is similar to human’s visionary senses to detect obstacles.
The sensor which simply measures IR radiation instead of emitting is called PIR or passive infrared. Generally in the IR spectrum, the radiation of all the targets radiation and some kind of thermal radiation are not visible to the eyes but can be sensed through IR sensors.
In this sensor, an IR LED is used as an emitter whereas the photodiode is used as a detector. Once an infrared light drops on the photodiode, the output voltage & resistance will be changed in proportion to the received IR light magnitude.
IR Sensor Working Principle
An infrared sensor includes two parts namely the emitter & the receiver (transmitter & receiver), so this is jointly called an optocoupler or a photo-coupler. Here, IR LED is used as an emitter whereas the IR photodiode is used as a receiver.
The photodiode used in this is very sensitive to the infrared light generated through an infrared LED. The resistance of photodiode & output voltage can be changed in proportion to the infrared light obtained. This is the fundamental IR sensor working principle.
The type of incident that occurred is the direct otherwise indirect type where indirect type, the arrangement of an infrared LED can be done ahead of a photodiode without obstacle. In indirect type, both the diodes are arranged side by side through a solid object ahead of the sensor. The generated light from the infrared LED strikes the solid surface & returns back toward the photodiode.
IR sensors use three basic Physics laws like Planck’s Radiation, Stephan Boltzmann & Wein’s Displacement.
- Planck’s Radiation Law defines that the temperature of any object is not equivalent to Zero
- Stephan Boltzmann Law defines that the whole energy which is generated at all wavelengths through a black body is associated with the total temperature.
- Wein’s Displacement Law defines that the temperature of different objects emits spectra that are maximum at various wavelengths and inversely proportional with temperature.
IR Sensor Module
The IR sensor module includes five essential parts like IR Tx, Rx, Operational amplifier, trimmer pot (variable resistor) & output LED. The pin configuration of the IR sensor module is discussed below.
- VCC Pin is power supply input
- GND Pin is power supply ground
- OUT is an active-high o/p
The main specifications and features of the IR sensor module include the following.
- The operating voltage is 5VDC
- I/O pins – 3.3V & 5V
- Mounting hole
- The range is up to 20 centimeters
- The supply current is 20mA
- The range of sensing is adjustable
- Fixed ambient light sensor
Types of IR Sensor
The classification of IR sensors can be done based on the application which includes the following.
- Active Infrared Sensors
- Passive Infrared Sensors
Active IR Sensor
This type of sensor includes both the emitter & the receiver which are also known as transmitter & receiver. In most situations, a laser diode or LED is used as a source. For non-imaging infrared sensors, LED is used whereas laser diode is used for imaging infrared sensors.
The working of an infrared sensor can be done through radiating energy, detected and received through the detector. Further, it is processed through a signal processor to fetch the required data. The best examples of active infrared sensors are reflectance & break beam sensors.
Passive Infrared Sensor
Passive Infrared Sensor (PIR) includes detectors only and this kind of sensor uses targets like infrared transmitters or sources. Here, the object will radiate the energy & detects it through infrared receivers. After that, a signal processor is used to understand the signal to obtain the required data.
The best examples of PIR sensors are bolometer , Pyro-Electric Detector, Thermocouple-Thermopile, etc. PIR sensors are available in two types like thermal IR sensor and quantum IR sensor.
Thermal Infrared Sensor
These types of sensors are independent of wavelength and they utilize heat-like energy sources. These are slow along with the response time as well as detection time.
Quantum Infrared Sensor
These types of sensors depend on wavelengths and the response time and detection time they have are high. These kinds of infrared sensors need repeated cooling for exact measurement.
IR Sensor Circuit
The application circuit of the IR sensor is an obstacle detecting circuit that is shown below. This circuit can be built with a photodiode, IR LED, an Op-Amp , LED & a potentiometer, The main function of an infrared LED is to emit IR light and the photodiode is used to sense the IR light. In this circuit, an operational amplifier is used as a voltage comparator and the output of the sensor can be adjusted by the potentiometer based on the requirement.
Once the light generated from the infrared LED can be dropped on the photodiode once striking an object, then the photodiode’s resistance will be dropped.
IR Sensor Circuit Diagram
Here, op-amp’s one of the input at threshold value can be set through the potentiometer whereas other inputs can be set by using the series resistor of the photodiode. Once the radiation on the photodiode is more, then the voltage drop will be more across the series resistor. In the operational amplifier, both the voltages are evaluated.
If the series resistor’s voltage is higher than the threshold voltage then the IC output is high. When the IC output is given to an LED then it will blink. So using a potentiometer, the threshold voltage can be adjusted based on the conditions of surroundings.
In this circuit, the arrangement of the IR receiver and the IR LED is a very essential factor. Once the infrared LED is placed directly ahead of the infrared receiver, then this arrangement can be known as Direct Incidence.
So in this case, nearly the whole radiation from the infrared LED will drop on the infrared receiver. Therefore there is a row of view contact among the IR Tx & Rx. If a target drops in this row, it blocks the emission while approaching the receiver by reproducing or absorbing the radiation.
Please refer to this link to know more about IR Sensor MCQs
The advantages of the infrared sensor include the following.
- Low power consumption
- Noise immunity is strong
- Detects motion when the light is present or absent
- These sensors are not affected by rust
- They do not need to get in touch with objects for detection.
- No data leakage because of the directionality infrared radiation of ray
- These are more modest in size and are more moderate.
- It responds very quickly as compared to thermocouples.
- It provides high reliability
The disadvantages of the infrared sensor include the following.
- Line of sight is necessary
- It can be affected based on the conditions of the environment like fog, rain, pollution, dust, etc
- These sensors can be blocked with common objects.
- The data rate transmission is not fast
- Range is limited
- High force IR signals can harm human eyes
The applications of the infrared sensor include the following.
- Rail Safety
- IR Imaging Devices
- Infrared Astronomy
- Optical Power Meters
- Night Vision Devices
- Sorting Devices
- Moisture Analyzers
- Missile Guidance
- Flame Monitors
- Remote Sensing
- Gas Analyzers
- Rail safety
- Exploration of Petroleum
- Testing of Anesthesiology
- Gas detectors
- Water analysis
Know more about Spectrum Analyzer and Wave Analyzer .
Thus, this is all about an overview of the Infrared Sensor or IR sensor. This kind of sensor is most frequently used in wireless technology wherever surrounding objects detection, functions of remote controlling, etc. The main features of this sensor are motion & heat sensing. The infrared region is not noticeable to human eyes. Here is a question for you, what are the different types of sensors available in the market?
What Really Happens When You Use an Infrared Sauna
What Really Happens to Your Body When examines the head-to-toe effects of common behaviors, actions and habits in your everyday life.
Foam rollers , massage guns and ice baths — there's certainly no shortage of fitness recovery tools out there. And after a tough lift, long run or high-intensity swim, they're a necessity, especially if you want peak performance.
Now, you can add infrared sauna to your list of treatments to try. There's a lot of buzz and speculation around infrared and its purported health benefits, with workout recovery being one of the most widely touted.
Video of the Day
Learn what happens to your body when you use an infrared sauna and how to recover as safely as possible.
Although infrared saunas are a safe recovery tool for most people, those with pre-existing conditions or health concerns should consult a doctor before they try their first session.
What Is an Infrared Sauna?
Unlike other dry saunas, infrared saunas have light panels either on the ceiling or walls, which glow red. These saunas usually only get to about 135 degrees (traditional saunas can go up to 195 degrees) but use the infrared lamps to warm your body directly, rather than heating up the air temperature, according to the Cleveland Clinic .
"Infrared light is invisible, just above red visible light," Joel Kahn, MD , an integrative cardiologist, says. "It is a form of light therapy, which involves getting exposed to sufficient intensity of infrared light to experience health benefits."
Infrared light has three different wave lengths, according to Dr. Kahn: near infrared waves (NIR), mid infrared waves (MIR) and far infrared waves (FIR). Each of these wavelengths are a little different, but the far waves are thermal and provide the heat that you actually feel, according to NASA . The shorter waves you can't feel at all.
What Happens When You Use an Infrared Sauna?
What exactly happens when you sit down in an infrared sauna? The infrared rays warm your body temperature and raise your heart rate, promoting increased circulation, according to the Mayo Clinic . That's how you get the benefits from the treatment (more on that below).
As you look around the sauna, you may notice a glowing red light, too. In some infrared saunas you may be able to change the light color. This light doesn't actually heat the room but rather provides light therapy, which may offer some additional health benefits, according to Joovv , a light therapy and infrared device company.
After you've settled in, you can expect to sweat quite a bit, despite that the temperature is lower than a standard sauna and there's no steam, per the Mayo Clinic. That's what makes infrared a better option for those who can't sit through super high heat.
You don't have to sit in the sauna too long to experience the benefits, but you probably shouldn't be in there much longer than 30 minutes, per the Cleveland Clinic.
You may be familiar with some claims that connect infrared sauna and improved blood pressure or reduced chronic pain. But there's currently no data that confirms these links, and more research is still needed to make any conclusions.
However, the infrared sauna can be a great day-to-day recovery tool for athletes and casual gym-goers (or anyone just looking for a refresh). Just as you might get massage or a cryotherapy session, infrared sauna is another treatment worth trying.
"One session will leave you feeling refreshed and rejuvenated," Dr. Kahn says. "Similar to exercise, the more you do it, the better the results."
3 Fitness Benefits of Using an Infrared Sauna
1. better recovery.
Increased blood flow is a big part of muscle recovery after exercise, according to the University of Rochester Medicine . When you train, your body forms new capillaries and brings fresh blood and oxygen into your muscles. This helps you lift, run and jump during your workout.
Your blood is also responsible from carrying your muscles' waste back to your kidneys, which is how your body rebuilds damaged muscle tissue. That's why improved circulation is such a big part of the recovery process.
Infrared saunas are one tool that can help speed your post-workout recovery process, according to Dr. Kahn. By increasing your body temperature and therefore heart rate, the sauna promotes circulation, helping heal your muscles.
2. Muscle Soreness Relief
Infrared saunas may also help relieve sore muscles, according to Dr. Kahn. Considering the infrared waves are able heat your body from within, they can better penetrate your muscles and tissues.
And this seemed to be the case for the athletes in a small July 2015 study in Springerplus . Athletes who sat in an infrared sauna with far-infrared waves experienced more recovery benefits, including muscle relief, than athletes who did no sauna.
"Far infrared is known to help with muscle soreness, and near infrared helps with tissue regeneration to help repair and grow muscles faster," Dr. Kahn says.
3. Improved Performance
In addition to your recovery, infrared can also have a positive affect on your performance, according to a September 2015 study in the Journal of Athletic Enhancement .
After sitting in a far-infrared sauna for 40 minutes each night for five days, athletes saw improved muscle activation, better explosive force production and speed performance compared to athletes who used no sauna. With that said, researchers did conclude that while infrared is a great supplemental recovery method, it shouldn't replace nutrition , sleep and muscle massage.
How to Use the Infrared Sauna
Before you jump into a long sauna session, start slow with a lower temperature, recommends the Cleveland Clinic. Begin with 5 to 10 minutes at a time and slowly increase the time length and temperature as you grow more comfortable.
Make sure you're well hydrated before you use the sauna and bring a water bottle with you. You may even want to consider adding some electrolytes to your bottle before you begin.
Bottom line: Chances are, the infrared sauna isn't going to work any magic — nothing can. But for those who want to incorporate a new recovery treatment it's worth a try. And as someone who has tried an infrared sauna herself, the peaceful alone time is an excellent bonus.
Want to Invest In Your Own At-Home Option?
- Sunlighten Portable Infrared Sauna (Price Varies, Sunlighten.com )
- Signature Infrared Sauna (Price Varies, Sunlighten.com )
- Cleveland Clinic: "Infrared Saunas: What They Do and 6 Health Benefits"
- University of Rochester: "It's All About Blood Flow"
- Springerplus: "Effects of Far-Infrared Sauna Bathing on Recovery From Strength and Endurance Training Sessions in Men"
- Journal of Athletic Enhancement: "Effects of Far Infrared Heat on Recovery in Power Athletes"
- NASA: "The Infrared Region"
Report an Issue
How to Write a Great Story in 5 Steps
Storytelling comes naturally to human beings. That’s why stories are all around us. When you talk to your friends, you tell stories. When you watch movies and read books, you’re watching and reading stories. When you study history and current events, you’re understanding the world through stories.
Why write a story?
We think a better way to phrase that question is: Why not write a story?
You have stories to tell. And whether you consider yourself a storyteller or not, you already tell them. By learning how to write a story, you can become a stronger communicator and even a better writer in other areas, like academic and professional writing.
Give your writing extra polish Grammarly helps you communicate confidently Write with Grammarly
What is a story?
A story is, essentially, an account of connected events. These events can be mentioned explicitly or implied. Take a look at this famous six-word story that’s often attributed ( incorrectly ) to Ernest Hemingway:
For sale: baby shoes, never worn.
There’s a lot you might infer from this sentence. From the story’s scant clues, you might form ideas about who’s offering the shoes, why they were never worn, and why the seller is seeking payment for them rather than passing them along for free. As you make these inferences, you’re putting together a story.
An account of events isn’t always a story, though. To be a story, the following five elements must be present:
In our six-word example above, the reader is tasked with inferring most of these elements from the few words provided, like who the characters are and the conflict that led to the baby shoes being placed for sale. Here’s another example of a piece of flash fiction (that’s only one letter long!):
“Cosmic Report Card: Earth,” by Forrest J. Ackerman: F.
Who’s the character? The group issuing the cosmic report card. What’s the setting? The cosmos. The plot? Planets receive grades based on their cosmic performance. The conflict? Earth’s failing grade. The theme? Humanity’s unsatisfactory performance.
While the story itself is only one letter long, the title is what really sets up the story and makes it possible for its single letter to communicate the story’s conflict and theme.
The only rule for writing a story is that it contain these five elements. Otherwise, a story can be just about anything you want it to be. It can be as short as just a few words or so long that it spans multiple novels.
Different types of stories
Every story is unique, isn’t it?
Every story might have a unique combination of characters, setting, plot, conflict, and theme, but every story can also fit into one of the seven plot types identified by journalist and author Christopher Booker. These plot types are:
- Overcoming the monster
- Rags to riches
- Voyage and return
These plot types are general outlines—two rags to riches stories can be dramatically different from each other, as can two stories in any other category. For example, Groundhog Day and Pride and Prejudice might have little in common on the surface, but they are both rebirth stories, meaning their plots recount how a flawed character faced an obstacle that forced them to become a better person. Grouping stories into these categories provides a framework for discussing, categorizing, and understanding stories.
As we discussed above, there’s no minimum length for a story. There also isn’t a maximum length. Stories are often categorized by their lengths, though. These are the most commonly used designations:
- Novel: More than 40,000 words
- Novella: 17,500–40,000 words
- Short story: 7,500 words or fewer
You might also be familiar with terms like novelette and flash fiction . These are subcategories that refer to stories of specific lengths within these larger categories. A novelette is longer than a short story but shorter than a novella, while flash fiction is a story told in typically fewer than 1,500 words.
Is an anecdote the same as a story?
A short account of events that doesn’t have the five elements that make a story is known as an anecdote . A quick recap of an interaction you had at work and a rundown of your experience at an amusement park are anecdotes.
A narrative , on the other hand, is a story. Just as the word composition can refer to a specific piece of writing or the art of writing, the term narrative can refer to a story itself or how a story is told. A story’s narrative is the way its plot elements are presented.
You probably know the story of “Goldilocks and the Three Bears.” The version you’re familiar with is a narrative told in the third person. Now imagine reading the story told from Mama Bear’s perspective—the narrative might include a passage like the following:
“I followed the small, dirty footprints from the front door to the kitchen, where I found somebody had ransacked the pantry and left crumbs all over.
‘Mama, come quick! Somebody’s in your bed!’ Papa Bear called from the bedroom. My heart pounding, I told Baby Bear to stay in the kitchen. I didn’t know what to expect . . . was this intruder dangerous?”
See how the storyteller’s perspective shapes the narrative? A narrative uses the point of view of the first or third person (and in some cases, second person.)
How to write a story in 5 steps
The story writing process is similar but not identical to the writing process you use for other kinds of writing. With a story, you need to make sure the five elements we listed above are present.
Here’s how to write a short story:
1 Find inspiration
The first step in writing a story is coming up with an idea. If the story is an assignment, you might already have a theme, a conflict, and/or other elements to work with. If not, look for inspiration. You can find inspiration anywhere—your own experiences, news stories, historical events, even just letting your mind wander down a “what if?” rabbit hole .
Watch. Listen. Observe. Take notes. Make a habit of doing all these things, and like writers throughout history, you will find inspiration all around you.
Once you have an idea for a story, brainstorm. Jot down all the ideas you have, including a rough outline of how the plot will progress. Let yourself play with ideas for characters, settings, plot points, and how the characters will resolve the main conflict (or not!).
With the basic points down, decide on the point of view you’ll use. This is where the idea of narrative comes into play—who is telling the story, and how does that character’s experience and perspective direct the narrative?
Next, create an outline for your story. A story outline is similar to outlines used for other kinds of writing, like academic papers. Your outline is a basic framework for your story that lists its key plot points and relevant details. For a lot of writers, a story’s outline is helpful in mapping out the scenes that make up the story.
4 Write the first draft
It’s time to write. Sit down and resist the urge to edit your story as you go along—just get all that story writing out of your system. You’ll have plenty of time to edit later.
5 Revise and edit your story
At this stage, it can be helpful to have others read your work. If you belong to a writing group, bring your story to them for constructive feedback. Readers are often better at catching plot holes, mischaracterizations, passages that can be strengthened, and other aspects that just aren’t working than the story’s author because they’re approaching it with fresh eyes.
If you don’t belong to a writing group, ask a few close friends or loved ones to read your work. We know it’s an intimidating ask . . . but if you want to write stories for anybody other than yourself to read, getting reader feedback is crucial!
With reader feedback, you can revise your story. This revised version is your second draft. At this stage, it might be ready to publish, but don’t forget that proofreading and checking your spelling and punctuation are important parts of the editing process. It can also be helpful to ask your readers to give it another read-through and provide any additional feedback they have on the second draft.
3 examples of stories
The Tortoise and the Hare , an allegory attributed to Greek storyteller Aesop, is one of many stories from the ancient world that have stood the test of time. Its theme is steady progress beats speed when one is pursuing a goal.
Another famous story is The Thousand and One Nights . This is a collection of stories within a larger story, similar to The Canterbury Tales and The Decameron . The main plot of The Thousand and One Nights is the story of Scheherazade, a young woman who marries the king, delaying her execution by telling him a new story every night. Eager to hear the story’s end, he delays the execution over and over, for a total of 1,001 evenings. This kind of story is called a frame story , as multiple shorter stories fit into a larger framework.
Frankenstein (its official title is Frankenstein: or, The Modern Prometheus ) is a well-known story by Mary Shelley published in 1818. The story, which has been republished and reimagined countless times since its initial release, explores themes of life and death and the conflict of humans vs. nature.
Writing a story FAQs
A story is an account of events that includes a setting, theme, plot, conflict, and at least one character.
How does a story work?
A story communicates a theme by telling the reader about a series of events, also known as a narrative. Within the narrative, a character faces at least one conflict, which often (but doesn’t always) change the character.
What are the different types of stories?
There are many different kinds of stories. The seven basic plot types are:
Get started in infrared (IR) photography.
Peer into an unseen world. Give your images an ethereal, surreal look using infrared light techniques in digital photography, film, and post-processing.
Not sure which apps are best for you?
Take a minute. We'll help you figure it out.
JUMP TO SECTION
What is infrared photography?
The history of infrared photography
IR photography turns reality into dream-like scenes
Make film or DSLR cameras into an IR camera
Tips and tricks for great infrared photos
Edit so you can’t forget it
Reflect a cool new world with infrared light.
Dive into IR light technology — its start, its history, and how it became popular with everyone from the US military to a musician and artist like Jimi Hendrix. Explore the IR “Wood Effect,” and discover how you can make film or DSLR cameras into infrared cameras simply by shooting images in specific ways. Get pro tips, like adjusting camera settings, to make your IR photos better. Plus, find details on Adobe Photoshop Lightroom tools that can help you create unique IR images in post-processing.
What is infrared photography?
The human eye cannot see infrared light. It lies beyond the visible light spectrum. But you can take photographs with an infrared filter or infrared film, which produces intriguing effects, to peer into this world. Colors and textures take on unique properties when reflected with infrared light, also known as IR light.
The history of infrared photography.
Robert Wood published the first infrared images in 1910. His photos were shot on experimental film that required very long exposures. For that reason, most of his subjects were landscapes. In World War I, infrared photos proved invaluable. The images could pierce the toxic gas that polluted the air. Troops were better able to determine differences between buildings, vegetation, and water to gather crucial intel.
In the thirties, Kodak and other camera manufacturers commercially released infrared film to the general public. Then, during World War II, the military continued its research into IR photography. It became a vital tool for modern warfare.
Two decades later, recording artists like Jimi Hendrix and the Grateful Dead further popularized the technique. They released album covers with infrared images that were popular due to their multicolored look. Now, the genre no longer requires special film to capture the images. Modern cameras and filters have made digital infrared photography more accessible than ever.
IR photography turns reality into dream-like scenes.
Named after infrared trailblazer Robert Wood, the most common result of infrared photography is called the “Wood Effect.” With the Wood Effect, infrared images of scenes reflect light so that foliage looks white and skies take on unusual colors, whether you shoot in black and white or false-color (color infrared) film. This effect is generally used in landscape photography to produce dreamy scenes. Skin takes on a smooth texture, perfect for haunting portraits. Certain stars and other constellations pop in infrared light. The ordinary will take on an otherworldly quality with this take on your standard photo.
Make film or DSLR cameras into an IR camera.
With recent advances in technology, infrared is a readily available feature for all photographers. Here are the ways you can shoot IR photos:
- Infrared film: The original method, this was the only way to shoot infrared for a long time, but it is used less now due to digital infrared photography’s ease of use. IR film is a great way to explore the world of IR light. You will record visible light as well as the infrared spectrum when using infrared film, so you will also need an IR filter to record pure IR images.
- Infrared filter: The most inexpensive way to experiment with IR photography, IR filters are similar to other camera filters. You attach them directly to your camera lens to capture the IR spectrum. While convenient, there are two things to consider with IR filters. From a technical standpoint, they won’t work on cameras with built-in infrared filters, as they block all infrared light from reaching the camera sensors. Creatively, infrared photography uses slower shutter speeds and longer exposures to capture images, so you will need a tripod to shoot effectively with an infrared filter.
- Camera conversion: A more expensive method, camera conversion puts a filter into your camera that lets infrared light through. A converted camera will produce sharper IR images that aren’t bound to a lens filter’s equipment requirements. Infrared conversion also removes the need for long exposures and external filters, but at a cost; you will not be able to capture normal photos anymore with your camera. Kolari Vision and LifePixel are two notable infrared conversion services.
Tips and tricks for great infrared photos.
Once you select a subject, know what infrared method you’re going to shoot in, and have all the corresponding gear, consider the following factors before shooting.
Adjust your camera settings.
Similar to other long exposure photography methods like landscape photography , infrared photography requires attention to detail when it comes to your settings:
- Wide angles will help achieve a better depth of field. Keep your ISO low to avoid overly exposed photos.
- Manually correct your focus. Autofocus may not work correctly when dealing with infrared light.
- Shoot your images in RAW mode to account for motion blur when mounted on a tripod. This will allow for more flexibility on corrective edits.
- Customize your white balance. You will not be able to gauge color well through your viewfinder once you put the filter on, so adjust your white balance ahead of time.
The brighter, the better.
Normal photography steers clear of harsh shadows or sunny days. Infrared photography runs toward it. Not only does more light give the photographer more infrared for imaging, it also makes shutter speeds more manageable and raises the intensity of the refracted IR light within the scene. This can deliver stunning effects. “I only shoot during bright, sunny weather or minimally overcast days, so you get that bright infrared light. It doesn’t work as well if you have a cloudy day,” says infrared photographer Kaitlin Kelly.
Experiment, experiment, experiment.
Infrared photography is easy to begin but tough to master. It can take years of dedication and patience to fully apply the technique. Don’t be afraid to just start shooting. “It’s not straightforward photography. Experimentation, playing around, and figuring out the look you want is fun because you can determine that for yourself,” says Kelly. Take notes on what you like and what’s not working to craft your unique infrared recipe.
Edit so you can’t forget it.
“Infrared photography reveals an unseen light, but at the same time, it challenges people to think about what reality is in a photograph,” photographer Richard Binhammer explains. You can adjust the reality even more with Adobe Photoshop Lightroom . Swap the red and blue channels with the channel mixer to make your false-color landscapes more psychedelic. Go monochromatic and make that blue sky black or turn bright green foliage snow white. Tone down your white balance to give your subjects an eerie, ghostlike effect.
The combination of Lightroom and infrared photography can make the dreamscapes of your mind’s eye a reality.
Kaitlin Kelly , Richard Binhammer
Share this article
Do more with Adobe Photoshop Lightroom.
You may also like
Please make sure that the "dexter.base.react.umd" and "dexter.base.consonantcardcollection" clientlibs have been added to the template's Page Policy
The Writing Cooperative
A 7-Step Guide to the Novel-Writing Process
Writing a great novel is never easy, but this process makes it easier.
I’ve been writing long fiction since the mid-late 90s. In all that time, I’ve collected a great deal of strong evidence in support of the idea that there is a specific way to write novels that almost invariably produces better novels than any other process. I could lay out all of that evidence in the form of a persuasive nonfiction article, but because I think the strongest argument for this process is its results, I’ll simply walk you through it. I’m confident that, if you follow this process in your own work, you’ll start to see many connections that you may have never seen before — connections that make a lot of sense and dramatically improve your long-form storytelling skills. I’ve used this process to coach more than 100 novelists of varying experience levels, and they’ve all had tremendously positive things to say about it.
Disclaimer: This guide is a heavily condensed, high-level overview of a process that can take hundreds, even thousands of hours. To exhaustively cover every facet of this process, I’d have to write an entire book or a whole series of articles. In the name of brevity and accessibility, I must omit most of the finer details here.
Next to each section heading, you’ll see a number expressed as a percentage. This number is a rough estimate of how much of the total time and energy invested in the entire project should be devoted to that stage of the process. For example, if the whole novel takes you 1,000 hours from start to finish (a typical amount of time), and the brain dump phase is 5%, you should spend about 50 of those 1,000 hours on the brain dump. There is some flexibility in these ratios, it’s not a hard-and-fast formula.
Step 1: Brain Dump (5%)
Virtually all novels begin with a single idea or a small set of related ideas. The first thing to do is to figure out whether those ideas can support a story of 100,000 to 300,000 words, and the way to start figuring that out is by doing a brain dump. Begin by writing down anything and everything that comes to mind about the story you want to tell, in no particular order. This could be character notes, ideas about settings, theme or plot possibilities, rough sketches of action scenes — anything at all.
You’ll be tempted to organize this data somehow. Don’t. That comes later, in the outline phase. Just barf everything onto the page as it comes to you. Trying to organize these fragments of thoughts at this stage will only distract you from the objective of this step: to get all of the raw data out of your head and into permanent form, on paper, so you can then see all the pieces and start playing with them.
Once you feel like you’ve gotten it all out, take a long break, at least a week. Then come back to your brain dump document and see if you have anything new to add to it. If you do, then take another long break when you’re done, and come back again later. Repeat as many times as necessary until you can’t think of anything else to add. If, at the end of this step, you strongly believe that there’s a good story here, you can move on to the next step.
Step 2: Choose a Theme and Plot-Theme (5%)
Although this is a small portion of the overall process in terms of time invested, it is by far the most important part. Don’t rush this. Just as the theme makes or breaks a nonfiction piece , your theme and plot-theme make or break your novel. To whatever extent your theme or plot-theme aren’t dialed in perfectly, the whole novel will suffer.
A novel’s theme is the summation of its abstract meaning. A theme can be overtly philosophical, implicitly philosophical, or (mostly) non-philosophical (all stories deal with ideas and values to some extent). For example, the theme of The Count of Monte Cristo is “the crucial difference between justice and vengeance.”
A novel’s plot-theme is the central conflict that determines the events of the plot. It is a summary of the concrete events that serve to illustrate the novel’s abstract theme. The plot-theme of The Count of Monte Cristo is “a conflicted man’s struggle for justice.” Virtually every significant action that Edmond Dantès takes during the story illustrates some aspect of the novel’s theme — the difference between justice and vengeance. This relationship between a novel’s theme and plot-theme is crucial to understand.
It’s important to note that, although a nonfiction theme is a complete sentence, fiction themes and plot-themes are not complete sentences. There are several reasons for this; I’ll cover these (and much more about themes and plot-themes) in a future article.
Step 3: Outline (50%)
That “50%” up there isn’t a typo. My fiction coaching clients often look at me like I’ve lost my mind when I tell them that at least half of the entire novel-writing process should be devoted to creating a robust outline.
I say this because the act of writing good prose — the actual text of the novel that readers will eventually read — is a subconscious activity, not a conscious one. Most fiction writers have been “in the zone” — a state in which the words of a manuscript or short story seem to come out almost automatically — but most writers find this difficult or impossible to turn on at will.
If you’ve done the outline well and correctly, you can be “in the zone” all the time once you start writing the manuscript. It’s a great feeling.
An A+ novel outline is long and highly detailed. It covers every major event, every character’s motives, every major choice that the characters make, and every consequence of those choices. Ensure that every major event — every instance of the plot-theme in action — illustrates the theme in some way.
In other words, a great outline is the tool that enables you to immediately and fully answer any question that anyone might conceivably ask about any aspect of your story. It’s the road map that you will use once you start “driving” — that is, writing the manuscript. It should come as no surprise that, if you start driving with an incomplete road map (or no map at all), your trip will be very difficult.
Writing a novel outline at this level of detail takes a long, long time. It’s a lot of thinking, introspecting, writing down notes and crossing them out, rambling into a voice recorder, and trying to stitch narrative threads together into a complete tapestry that makes perfect sense. You’ll hit many roadblocks. You’ll have to abandon ideas that seemed good, delete big chunks of text, and start all over, probably more than once. But I promise you, it’s worth doing. Eventually, as long as you stay disciplined and keep at it, the pieces will start to fall into place. You’ll know it when it happens. You’ll realize, with full clarity and certainty, that everything now fits together nicely, all the important questions have satisfying answers, and you’ve got a tight, compelling story that deserves to be told.
I won’t lie to you, the outline phase sucks at times. It can be a slog. But your future self — the version of you who has to write the manuscript — will thank you for powering through it.
Resist the temptation to start writing the manuscript before you’ve had that moment of clarity, before you know with certainty that your outline is done. Jumping the gun here will cause more problems than it solves.
Step 4: Get the Story Out (20%)
If you’ve put together a complete and solid outline, congratulations — the hardest part of writing a novel is done and behind you! The first draft of your manuscript should now be relatively quick and painless because your conscious mind has already built a smooth, level road that your subconscious mind can drive on easily and comfortably, at a consistent speed.
Just as you were tempted to organize information during your brain dump, you’ll be tempted to edit your first draft as you go. Again, don’t. Just get the story out, as I like to say. You can correct major typos or fill in previously undiscovered plot holes as you go, but other than that, just accept the fact that your rough draft is rough and keep writing. (Filling in truly massive plot holes may require returning to your outline and fixing them there before you come back to the manuscript.)
If you find yourself struggling with writer’s block or deeply dissatisfied with the way the pieces of the story are coming together, that’s usually a sign that there’s still something wrong or missing in your outline. Take a break for a while, then go back to the outline and scan carefully for problems. Find and fix them before coming back to the manuscript.
Step 5: Take a Long Break
If you’re anything like me, by the time you type the last word of the last chapter in your first draft, you will be thoroughly sick of this story. You may feel like you never want to see it again. That’s normal and healthy. It will pass.
I find that one month is the bare minimum amount of time to let the first draft marinate. Writing a novel is extremely mentally taxing. Take the break you’ve earned so that, later, you can start editing with fresh eyes and replenished willpower.
Step 6: Self-Editing (10%)
Some writers claim that nobody is objective enough to edit their own work properly. Based on more than a quarter-century of writing and editing experience, I find this claim to be entirely baseless. Self-editing is necessary but not sufficient for a great novel.
Once you’ve fully recovered from your first draft, read through your entire manuscript slowly . Do your best to pretend that you’ve never read this story before. In fact, pretend it was written by someone you mildly dislike, so you have an extra incentive to look for problems. When you get to the point where you can say, “Wow, someone I don’t like wrote this story, but I have to admit that it’s excellent,” that’s how you know you’ve got a revised draft that’s ready to proceed to the next stage of editing.
Self-editing almost invariably takes multiple rounds. Take breaks at least a few weeks long between rounds. When even your most eagle-eyed scans can find no major problems in your draft, you’ve done all you can in this phase.
Step 7: Get a Top-Tier Editor (10%)
No matter how good a writer you are, and no matter how great you are at self-editing, a qualified editor (who is not you) will always make your work better than it otherwise would have been. Finding an editor who is both highly qualified and who works well with you is a skill all its own. (It’s yet another thing on my list of guides to write.) For now, let’s assume you’ve already pulled off that Herculean task.
An excellent novel editor is compassionately vicious. I’ve worked with far too many editors who are so afraid of hurting the writer’s feelings (or of losing a paying client) that they fail to point out major problems in the manuscript. A top-shelf editor pulls no punches — they’ll identify every potential problem they can find, but they’ll do it gently and constructively, in a way that makes you believe that their goal is to help you publish the best story you possibly can. In other words, a superb novel editor will tear your work apart as an act of creation, not as an act of destruction.
You may be tempted to skip ahead to this step before you’ve fully completed the self-editing phase. Once again, resist that temptation. Don’t hire a professional editor until you’ve self-edited your manuscript to the point that it is, in your estimation, the best it can possibly be. (It’s not — it’s just the best you can possibly make it without help .) If you hire an editor prematurely, you’ll probably find their advice more confusing than clarifying, and you’ll end up paying them way more than necessary because of all the extra time they spend fixing things you could have fixed on your own.
Proofreading is crucial, but don’t bother until you and your editor both agree that the manuscript is otherwise good to go from both developmental and line-editing perspectives.
There you have it — an agonizingly difficult, painfully long process distilled down to just over 2,000 words. I think you’ll find that these general principles, executed slowly and carefully in this order, make for a better final product than any other novel-writing process can produce, especially in terms of consistency across multiple novels. Of course, this brief guide leaves many technical questions unanswered, but I’ll cover some of those questions in future guides that will be much narrower in scope.
More from The Writing Cooperative
Medium’s largest collection of advice, support, and encouragement for writers. We help you become the best writer possible.
About Help Terms Privacy
Get the Medium app
Tim White is a writer, editor, game designer, and small business owner based in Arizona. Contact: timwhitewriting.com
Text to speech
- Russia-Ukraine war
- Social Security
- Donald Trump
- Content from IASIC
- Trump spends days workshopping nicknames for DeSantis: report Campaign - 10m 45s ago
- Christie jabs at lack of crowd for Trump at CPAC: ‘That room was half-full’ Sunday Talk Shows - 24m 29s ago
- Chris Christie on Trump: ‘He’s not what he used to be’ Sunday Talk Shows - 34m 54s ago
- Worried about the debt: Tax the rich Finance - 35m 52s ago
- House Intel chair: FBI is ‘not being forthcoming’ on classified docs Sunday Talk Shows - 54m 37s ago
- Manchin on endorsing Biden in 2024: ‘Let’s see who’s involved’ Sunday Talk Shows - 1h 14m ago
- Transportation post has become political nightmare for Buttigieg Administration - 1h 35m ago
- Hutchinson says Trump’s 2024 message appeals to ‘angry mob’ Sunday Talk Shows - 1h 38m ago
Florida bill would require bloggers to register before writing about DeSantis
A bill proposed this week by a Republican state senator in Florida would require bloggers who write about Gov. Ron DeSantis (R-Fla.), his Cabinet officers and members of the Florida legislature to register with the state.
Bloggers who receive compensation for a given online post about an elected state officer would have to register with the Florida Office of Legislative Services or the Commission on Ethics — though the requirement would not extend to the websites of newspapers or similar sites.
“If a blogger posts to a blog about an elected state officer and receives, or will receive, compensation for that post, the blogger must register with the appropriate office … within 5 days after the first 164 by the blogger which mentions an elected state officer,” reads the bill , introduced by Republican state Sen. Jason Brodeur.
If additional posts about elected state officers were to be posted, the blogger would have to file monthly reports detailing where, when and by whom the post was published, plus the amount of compensation received. Failure to file reports could lead to fines.
The elected state officers covered by the proposed “Information Dissemination” bill are defined as “the Governor, the Lieutenant Governor, a Cabinet officer, or any member of the Legislature.”
A blog is defined in the bill as “a website or webpage that hosts any blogger and is frequently updated with opinion, commentary, or business content” and a blog post as “an individual webpage on a blog which contains an article, a story, or a series of stories.”
The Hill has reached out to the governor’s office for comment.
More State Watch News
Sen. sherrod brown ‘not entirely satisfied’ with norfolk southern response to second ohio train derailment, dc mayor warns of ‘slippery slope’ with congress’s ‘meddling’, nevada democrats oust incumbent, elect ‘unity’ candidate as party chair, three things to know about what critics are calling mississippi’s ‘jim crow’ bill, video/hill.tv, see all hill.tv, see all video, rising: march 5, 2023, rising: march 4, 2023, fbi dir accuses china of obfuscating covid investigation, poll finds ron desantis top choice for 2024 gop nominee, top stories.
- Transportation post has become political nightmare for Buttigieg
- Republicans see growing primary field as boon for Trump
Jeffries: ‘No indication’ Capitol Police vetted Jan. 6 footage Tucker Carlson plans to air
- Democrats vow fierce fight if GOP cuts Medicaid
- Jeffries: ‘No indication’ Capitol Police vetted Jan. 6 footage Tucker ...
- Shark Tank’s Kevin O’Leary blasts Ocasio-Cortez: ‘She kills jobs by the ...
- Twitter discloses another possible government censorship effort
- What Biden might try next if his student loan forgiveness plan is struck down
- Three things to know about what critics are calling Mississippi’s ‘Jim ...
- Hogan says he won’t run for president in 2024
- It was the most visited national park in 2022, but it isn’t exactly a park
- Chris Christie on Trump: ‘He’s not what he used to be’
- Hutchinson says Trump’s 2024 message appeals to ‘angry mob’
- Numerical coincidence prompted $754M Powerball winner to buy ticket: ‘It was ...
- Former Trump aide Kellyanne Conway to divorce husband after 22 years
- Sununu predicts Trump won’t be 2024 GOP nominee: ‘That’s just not going ...
- Trump easily wins CPAC straw poll
- Five takeaways from this year’s CPAC
- Christie jabs at lack of crowd for Trump at CPAC: ‘That room was half-full’
Watch live: White House monkeypox response team holds briefing
- Main content
A new bill in Florida would require bloggers writing about Ron DeSantis to register with the state or be fined
- A Florida senator filed a bill mandating that anyone blogging about DeSantis must register with the state.
- S.B. 1316 mandates that bloggers must register within five days of their first post.
- The proposed legislation has not been put to a vote yet, and it's unclear if DeSantis supports it.
A new bill introduced in Florida would require any blogger who writes about Gov. Ron DeSantis to register with the state.
The bill was introduced in the Florida Senate on February 28 by GOP lawmaker Jason Brodeur. S.B. 1316 would require any blogger who writes about DeSantis — and is paid for their work — to register with the state ethics commission or the Florida Office of Legislative Services. They must do so within five days of their first post.
Bloggers would also be required to register with the state if they write anything about Florida's lieutenant governor, a cabinet officer, or any member of the Florida legislature, per the bill.
S.B. 1316 would mandate that bloggers submit monthly reports about their work if they write about elected officials, including how much payment they received for their articles, rounded to the nearest $10, and the name of the "individual or entity" who paid them.
Writers who do not file their reports on time should be fined $25 a day, the bill suggests. A blogger can be fined a maximum of $2,500, the bill reads.
Brodeur's suggested law does not appear to apply to news organizations but instead would target individual bloggers who write about DeSantis and other officials.
The proposed legislation has not yet been put to a vote. It's unclear if DeSantis personally supports Brodeur's bill.
Brodeur told the website Florida Politics that he believes "paid bloggers are lobbyists who write instead of talk."
Ron Kuby , a lawyer in New York specializing in free speech, told NBC News that Brodeur's proposal would violate the First Amendment.
"We don't register journalists. People who write cannot be forced to register," Kuby told NBC News.
The suggestion that more restrictions be placed on people writing about DeSantis stands in direct contrast to the governor's messaging that Florida should have as much freedom as possible. In July, Insider saw a fundraising page from DeSantis where he was selling a gold "Freedom Team Membership Card."
Representatives for Brodeur and DeSantis did not immediately respond to Insider's requests for comment.
The ACLU of Florida, the First Amendment Foundation, and the Marion B. Brechner First Amendment Project at the University of Florida did not immediately respond to Insider's requests for comment.
DISCOVERY OF INFRARED In 1800, William Herschel conducted an experiment measuring the difference in temperature between the colors in the visible spectrum. He placed thermometers within each color of the visible spectrum. The results showed an increase in temperature from blue to red.
Photons at infrared wavelengths do have less energy than those in the visible band. As a result, they do "have such a momentum as to be unfit for vision." He was not looking a century ahead but a century back—to Isaac Newton's experiments with light in the late 1600s.
Originally proposed in 1971 as a mission based on the Space Shuttle, five years before the pioneering free-flying survey mission IRAS was conceived, Spitzer entered a saga of funding squeezes ...
infrared radiation, that portion of the electromagnetic spectrum that extends from the long wavelength, or red, end of the visible-light range to the microwave range. Invisible to the eye, it can be detected as a sensation of warmth on the skin.
British astronomer William Herschel discovered infrared light in 1800, according to NASA. In an experiment to measure the difference in temperature between the colors in the visible spectrum, he...
Pay just £4 per issue when you subscribe to BBC Sky at Night Magazine today! Infrared is a form of electromagnetic radiation exactly like visible light, but with a longer wavelength. The infrared waveband extends from 0.8 to 1,000 microns. In astronomy, infrared enables us to view elements of the Universe that are invisible to the human eye.
Here's how to understand these images: The first image above shows a woman who ordered something warm to drink. The waitress hands her a bright white cup. The second image shows a woman nearby ...
Your mitochondria generate light based on changes in the energy levels of quantum particles (electrons and protons). The burning of energy within a cell is a combustion reaction that liberates infrared and red light from the substrates (fats, proteins, and carbohydrates). How much energy a cell can generate depends upon a range of factors like ...
Infrared thermography can be carried out using two different approaches:. Active infrared thermography: This technique employs an external source to add extra energy to the study object, generating internal heat-flow that increases the temperature. The most important types of active infrared thermography include-Pulsed thermography is the most common type of thermal stimulation due to its easy ...
infrared. An invisible band of radiation at the lower end of the visible light spectrum. With wavelengths from 750nm to 1mm, infrared starts at the end of the microwave spectrum and ends at the beginning of visible light. Infrared transmission typically requires an unobstructed line of sight between transmitter and receiver.
Infrared was discovered by British astronomer Sir William Herschel in 1800. Herschel knew sunlight could be separated into separate components, a step accomplished by refracting the light through a glass prism. He then measured the temperatures of the different colors that were created.
Nevertheless, it is perfectly possible to write a great news story that takes the contents of a research paper as its starting point. Here are some guidelines. 1. Find a good paper Thousands of...
Infrared Communication. Infrared band of the electromagnet corresponds to 430THz to 300GHz and a wavelength of 980nm. The propagation of light waves in this band can be used for a communication system (for transmission and reception) of data. This communication can be between two portable devices or between a portable device and a fixed device.
Here are 7 steps in writing a good news story for school or for your english or journalism class: Choose a current, newsworthy event or topic to write about. Conduct timely, in-person interviews with witnesses. Establish the "Four Main Ws". Plan your article. Create an outline.
Infrared Spectroscopy generally refers to the analysis of the interaction of a molecule with infrared light. The IR spectroscopy concept can generally be analyzed in three ways: by measuring reflection, emission, and absorption.
Infrared Spectroscopy is the analysis of infrared light interacting with a molecule. The portion of the infrared region most useful for analysis of organic compounds have a wavelength range from 2,500 to 16,000 nm, with a corresponding frequency range from 1.9*1013 to 1.2*1014 Hz. Photon energies associated with this part of the infrared (from ...
Infrared radiation can be the source of heat as they have thermal properties. When infrared radiation strikes the oxygen or nitrogen molecules, it makes the molecules move faster as they gain more energy. So it can be concluded that infrared radiation makes materials hotter and can be used as a heat source. Where do we use Infrared Rays?
The near IR region is used on fiber optic & IR sensors, the mid-IR region is used for heat sensing and the far IR region is used in thermal imaging. The range of frequency for IR is maximum as compared to microwave and minimum than visible light. This article discusses an overview of the IR sensor and its working.
3 Fitness Benefits of Using an Infrared Sauna. 1. Better Recovery. Increased blood flow is a big part of muscle recovery after exercise, according to the University of Rochester Medicine. When you train, your body forms new capillaries and brings fresh blood and oxygen into your muscles. This helps you lift, run and jump during your workout.
To be a story, the following five elements must be present: Setting. Plot. Conflict. Character. Theme. In our six-word example above, the reader is tasked with inferring most of these elements from the few words provided, like who the characters are and the conflict that led to the baby shoes being placed for sale.
With recent advances in technology, infrared is a readily available feature for all photographers. Here are the ways you can shoot IR photos: Infrared film:The original method, this was the only way to shoot infrared for a long time, but it is used less now due to digital infrared photography's ease of use.IR film is a great way to explore the world of IR light.
This is why I encourage all copywriters to learn how to tell a stock story . When you learn this valuable skill, you too, will rise to the top of the A-list of copywriters, find yourself in high ...
The first thing to do is to figure out whether those ideas can support a story of 100,000 to 300,000 words, and the way to start figuring that out is by doing a brain dump. Begin by writing down anything and everything that comes to mind about the story you want to tell, in no particular order. This could be character notes, ideas about ...
A bill proposed this week by a Republican state senator in Florida would require bloggers who write about Gov. Ron DeSantis (R-Fla.), his Cabinet officers and members of the Florida legislature to ...
The bill, S.B. 1316, requires anyone who writes "an article" or "a series of stories" about DeSantis and gets paid for it to register with the state.