Earth is under constant threat by thousands of asteroids.
1. What is an asteroid?
Asteroids are metallic, rocky bodies without atmospheres that orbit the Sun but are too small to be classified as planets. Known as "minor planets," thousands of asteroids congregate in the so-called main asteroid belt: a vast, doughnut-shaped ring located between the orbits of Mars and Jupiter.
Many asteroids, however, are classified as Near Earth Objects, meaning their orbit brings them in close proximity with our planet. While most of these asteroids do not pose a threat to us, thousands of them do.
As our planet swings through the solar system, it is important for us to study the orbits of existing and newly discovered potentially hazardous asteroids, in order to predict future collisions and hopefully prevent them.
2. Asteroids are all around us
Currently, over 500,000 asteroids have been identified and cataloged in our Solar System, and new ones are being discovered all of the time.
As of April 09, 2014, 10,906 Near-Earth Objects (NEO) have been discovered. Of these asteroids,1,466 have been classified as Potentially Hazardous Asteroids (PHAs). The orbits of these asteroids may cross our orbit, potentially colliding with the Earth, with catastrophic results.
3. Earth is getting hit all the time!
Every day, the Earth is bombarded with more than 100 tons of dust and sand-size particles. Many of the incoming particles are so small that they are destroyed in the Earth's atmosphere before they reach the ground. These particles are often seen as meteors or shooting stars.
Recent sensor data has shown that 26 explosions more powerful than a kiloton of TNT have been detected on Earth since 2001, all of which are due to asteroid impacts. This suggests that asteroid impacts are not rare, and are in fact are 3-10 times more common than previously thought.
According to former astronaut Ed Lu, the fact that none of the asteroid impacts detected was detected in advance is proof that "the only thing preventing a catastrophe from a 'city-killer'-sized asteroid is blind luck."
4. Past impacts have changed the Earth (not done)
Throughout the history of our planet, asteroid collisions have played a large part in shaping our geology, and may be responsible for global extinctions.
When large impacts occur, a crater is formed. Because of the dynamic geological nature of the Earth's surface, many craters are covered by forests or eroded by wind and rain. Despite this erosion, satellite imaging has identified craters left by past impacts.
5. It's only a matter of time (not done)
Of the cataloged potentially hazardous asteroids, those listed above will be approaching Earth this month. While the chances are small, a collision is still possible. In order to determine how much of a threat these asteroids pose, more research is needed.
6. What can you do? (not done)
Numerous government and private organizations are working to detect and catalog existing and new asteroids all the time, but the general public remains unaware of the threat of large asteroid impacts. By increasing public awareness, we hope to garner support for these projects, and help people understand how important it is.
If you are concerned about the potential threat of asteroid impact, and would like to do your part to address the risk, here are some actions you can take:
(insert list of organizational efforts, and actions that the average person can take to draw attention to the issue)
"Bryophytes, especially mosses, colonize bare rock surfaces, leading ultimately to the initiation of soil formation. This in turn produces a substratum attractive to seed plant colonists that invade these mossy sites and, through their shading, eliminate the pioneer mosses but create a shaded habitat suitable for other bryophytes. These new colonists, in turn, are important in nutrient cycling in the developing forest vegetation."
2. Hydroponics for limited space (pre-settlement, on space shuttle or other limited space environment)
"The volatile organic analyzer (VOA) is an atmospheric analysis device on ISS that uses a gas chromatograph and ion mobility spectrometer to detect, identify, and quantify a selected list of volatile organic compounds (i.e., ethanol, methanol and 2-propanol) that are harmful to humans at high levels in a closed environment, such as ISS. The ISS also utilizes the POTOK air filtration device employed by Roscosmos to disinfect and inactivate microorganisms by electrostatic pulses and charged ions.
The crew keeps microbes under control on ISS through periodic scheduled sanitation of the ISS.
Missions to beyond low Earth orbit will increase the length of time that astronauts live and work in closed environments. To complete future long-duration missions the crews must remain healthy in closed environments, hence future spacecraft must provide sensors to monitor environmental health and accurately determine and control the physical, chemical and biological environment of the crew living areas and their environmental control systems."
Questions will taken via Twitter with the hashtags #GrowFoodMartian or #DeployGreen or the Q&A feature of Hangout on Air. We will also be checking the hackpad , which is really the best repository for all questions on this challenge.
Marina MDevices for spoilage detection currently in the research phases:
"A polymer material that raises a red flag, changing color in the presence biogenic amines, compounds produced by the bacterial decay of food proteins. In laboratory tests, the polymer identified and distinguished between 22 different kinds of key food-spoilage amines with 97 percent accuracy.
Researchers also used the polymer to check the freshness of a tuna by detecting the amount of amines present in the sample. "The sensitivity of the described assay is better than the typical mammalian sense of smell and is able to detect this nonvolatile amine at hazardous levels before the fish would begin to smell rancid," the report states. The approach also shows promise for detecting spoilage in other food types, it adds.
The article "A Food Freshness Sensor Using the Multistate Response from Analyte-Induced Aggregation of a Cross-Reactive Poly(thiophene)" is scheduled for the Aug. 16 issue of ACS' Organic Letters"
"sequences of oligodeoxyfluorosides (ODF; fluorophores attached to a DNA backbone), whose fluorescent response upon UV excitation changes colour in the presence of gaseous analytes produced by bacteria or mould.
In addition, the dyes can be printed on paper using commercial inkjet printers, which would give them the ease of use and widespread applicability of litmus paper"
3. Tao, H., Brenckle, M. A., Yang, M., Zhang, J., Liu, M., Siebert, S. M., Averitt, R. D., Mannoor, M. S., McAlpine, M. C., Rogers, J. A., Kaplan, D. L. and Omenetto, F. G. (2012), Silk-Based Conformal, Adhesive, Edible Food Sensors. Adv. Mater., 24: 1067–1072.
An array of passive metamaterial antennas fabricated on all protein-based silk substrates were conformally transferred and adhered to the surface of an apple. This process allows the opportunity for intimate contact of micro- and nanostructures that can probe, and accordingly monitor changes in, their surrounding environment. This provides in situ monitoring of food quality. It is to be noted that this type of sensor consists of all edible and biodegradable components, holding utility and potential relevance for healthcare and food/consumer products and markets.
The bryophytes are autotrophic cryptogams and an important component of the flora. They occur throughout the globe in different habitats, particularly on moist and shady places. They grow on soil, rocks, tree trunks, branches, leaves, buildings, old monuments etc. and in wetlands.
Environmental pollution is increasing day by day, posing a very serious problem for the flora and fauna. A large number of pollutants including heavy metals are adversely affecting our environment. Heavy metals are emitted from solid fuel combustion, vehicular emissions and in industrial processes. Bryophytes are widely used as bio-indicators for their unique and very specific responses.