Today, billions and billions of stars dazzle the Universe with their fierce fires, looking like a sea of glimmering rhinestones, sparkling in the bewitching, beguiling darkness of space. But, in the distant future, the stars will all go out, the planets and their moons will vanish, and even the black holes will finally evaporate away–and all that will remain, as a testament to what once existed, will be an immense Void of featureless Nothingness. On August 10, 2015, an international team of astronomers studying more than 200,000 galaxies, announced that they have measured the energy generated within a large swath of space more precisely than ever before, and that this represents the most comprehensive assessment of the energy output of the nearby Universe. The findings were presented in August 2015 at the International Astronomical Union’s (IAU’s) General Assembly in Honolulu, Hawaii, and they confirm that the energy produced in a section of the Universe today is only about half of what it was two billion years ago. This fading is occurring across all wavelengths from the ultraviolet to the far infrared–showing that the Universe is slowly dying.
The study, which is part of the Galaxy And Mass Assembly (GAMA) project, the largest multi-wavelength survey ever conducted, involved a large number of the world’s most powerful telescopes.
“We used as many space and ground-based telescopes as we could get our hands on to measure the energy output of over 200,000 galaxies across as broad a wavelength range as possible,” noted Dr. Simon Driver in an August 10, 2015 IAU Press Release. Dr. Driver, of the International Centre for Radio Astronomy (ICRAR), the University of Western Australia, heads the large GAMA team.
Albert Einstein’s Theory of Special Relativity (1905) describes a Universe that has frequently been likened to an artist’s canvas. The artist paints lines and points on this marvelous canvas that will display the past, present, and future of the Cosmos. This strange canvas is the stage where the drama is being played out, rather than the drama itself. The remarkable achievement uniting the stage with the drama came a decade later when, in 1915, Einstein presented to the world his revolutionary Theory of General Relativity. According to General Relativity, Space becomes a star actor in this greatest of all stage plays, In this play, Space tells mass how to move, and mass tells Space how to curve. Space is just as flexible as a child’s trampoline. If a child tosses a heavy bowling ball onto the fabric of the trampoline, it will create a dimple in the fabric. Imagine that bowling ball to be a heavy massive object, such as a star. If a handful of marbles are then thrown onto that marvelous trampoline, they will travel along curved paths around the massive “star”, that has created a dimple in the fabric. Take the bowling ball off the trampoline, and the marbles will then start to follow straight paths, rather than curved ones. The trampoline represents Space, and it curves accordingly when the mass of the bowling ball–or star–warps it. This is the way planets circle around a real star. The marbles–or “planets”–wander the way that the “star’s” warpage of Space dictates. Therefore, the trampoline becomes just as much of an actor in this universal drama as the bowling ball and the marbles. Space plays just as big a role as a star and its retinue of planets in this play. The curtain will not close on the stage as long as the main players exist.
At present, it appears that the expansion of the Universe will continue on and on, perhaps forever–and the Cosmos is destined for a quiet, cold, dark sleep in the devastating grave of eternal Nothingness. Our Universe, in this particular scenario, will only gradually perish, eventually evolving into a grim, ghostly wasteland of black holes and dying stars. By the time our Universe is 1 trillion trillion trillion, trillion trillion trillion years old, the black holes themselves will have evaporated in wandering streams of particles, which may ultimately bind together to form individual “atoms” that are bigger than the size of today’s visible Universe. However, even these will eventually decay, leaving behind only a featureless, silent, grim Void.
Today, galaxies, galaxy clusters, and superclusters, are strung out like glittering beads along a transparent Cosmic Web like glistening dewdrops suspended on the web of a garden spider. These star-lit, galactic structures are embedded in the massive, web-like material, the nature of which is unknown–although theories to explain it abound. This invisible, transparent material is called the dark matter–because scientists are “in the dark” about its identity. However, it is generally thought that the dark matter is composed of exotic, non-atomic particles that do not interact with light, which explains its beguiling invisibility. The dark matter accounts for approximately 26.8% of the mass-energy of the Universe.
Even more plentiful, and more bewildering, is the dark energy, a truly bizarre and mysterious force that is causing the Universe to accelerate in its expansion. Often considered to be a property of Space itself, the dark energy accounts for the lion’s share of the mass-energy of the Universe, at 68.3%
As lovely and as dazzling as the stars are, they are merely the sprinkles on the Cosmic ice cream sundae. The immense, shining, starry galaxies are embedded in halos of the weird dark matter. Even though scientists have not directly observed the dark matter, they are almost certain that it is really there because of its gravitational influence on objects that can be seen. Dark matter can only influence so-called “ordinary” atomic matter and light through the force of gravity.
So-called “ordinary” atomic matter is really very special and extraordinary stuff. The undisputed runt of the Cosmic litter, it accounts for literally all of the elements in the familiar Periodic Table. Even though “ordinary” matter represents a mere 4.9% of the Universe’s mass-energy, it is the material of planets, moons, stars, and people. It is really very special–the stuff of life itself.
Most scientists think that the Universe was born about 13.8 billion years ago in the Big Bang. It began as an unimaginably small Patch, much tinier than a proton, and then–in the smallest fraction of a second–expanded like a balloon on steroids to attain macroscopic size. This brief period of exponential expansion is termed inflation. Even though inflation remains a theory, at this point, the most recent observations and measurements strongly suggest that it is the most likely explanation (currently known) that could have caused the Universe to evolve in the way that it apparently has.
The Universe Is Dying
It has been known since the 1990s that the Universe is dying. The fact that the Universe is fading away into Nothingness, like the lingering, haunting grin of the Cheshire Cat in Lewis Carroll’s Alice In Wonderland, has been known for about a generation. The significance of the study, presented at the 2015 IAU General Assembly in Honolulu, is that it shows that this Cosmic dimming is occurring across all wavelengths from the ultraviolet to the infrared. This constitutes the most comprehensive study of the energy output of the local Universe.
“The Universe will decline from here on in, sliding gently into old age. The Universe has basically sat down on the sofa, pulled up a blanket and is about to nod off for an eternal doze,” Dr. Driver commented in the August 10, 2015 IAU Press Release.
The team of astronomers studied the well-known and continual drop in the Cosmic stellar birth-rate. Stellar formation peaked when the Universe was less than 50% its present age–approximately 3.5 billion years after the Big Bang. Ever since that ancient time, the galaxies have produced fewer and fewer numbers of sparkling, fiery baby stars. Galaxy growth has followed this same evolutionary pattern, since galaxies build themselves up partly by producing stars. More surprisingly, there has also been an evolutionary drop in the growth-rate of supermassive black holes. Supermassive black holes, that weigh-in at millions to billions of times more than our Sun, are thought to hide in the dark and mysterious hearts of all the large galaxies in the Universe.
This study is a triumph because of the immensity of the sample size, that combines data derived from a trio of space missions, in addition to a duo of ground-based facilities, to produce a monumental and truly magnificent data set–GAMA. The end result is a fantastic view of 221,373 galaxies at all electromagetic wavelengths.
All of the energy in the Universe was born in the Big Bang, with some percentage of it locked up as mass. Stars sparkle brilliantly by converting mass into energy, as described by Albert Einstein’s famous equation E=mc squared. The GAMA study mapped and modelled all of the energy generated within a large volume of space today and at different times in the past.
“While most of the energy sloshing around in the Universe arose in the aftermath of the Big Bang, additional energy is constantly being generated by stars as they fuse elements like hydrogen and helium together. This new energy is either absorbed by dust as it travels through the host galaxy, or escapes into intergalactic space and travels until it hits something, such as another star, a planet, or, very occasionally, a telescope mirror,” Dr. Driver continued to explain.
The team of astronomers plan to expand the study to map energy production over the entire history of the Universe. They hope to do this using a large number of new facilities, including the world’s largest radio telescope, the Square Kilometre Array, scheduled to be constructed in Australia and South Africa over the next decade.