We’re all screwed. Well, if you’re planning to stick around for a few more billion years.
Researchers have found that galaxies are losing energy at a rather alarming rate, and confirm that all energy in the universe will eventually dissipate into nothingness. A study of 200,000 galaxies found they had lost half their energy in just two billion years. “The universe is slowly dying,” a statement from the European Southern Observatory (ESO) somberly says.
The theory that the universe is dying through an increase in entropy is not new, but this is the most extensive analysis yet of what’s going on. The energy output of a large portion of space containing the galaxies was measured more precisely than ever before. It was studied in 21 wavelengths, from ultraviolet to the far infrared, and all were found to be decreasing. It was part of the Galaxy and Mass Assembly (GAMA) project, which is using the most powerful telescopes around the world to study the cosmos.
“We used as many space and ground-based telescopes we could get our hands on, to measure the energy output of over 200,000 galaxies across as broad a wavelength range as possible,” said Simon Driver from the International Centre for Radio Astronomy Research (ICRAR) in Australia, who leads the large GAMA team, in a statement.
What’s happening is this: stars use up their fuel and dissipate it as light and heat. When certain stars end their lives in cataclysmic supernova explosions, they can fuel the birth of new stars, but ultimately all of that energy will spread out so much that no new stars can form from it. In the galaxies studied, the rate of star formation was found to decrease by a factor of two over two billion years. The researchers came to their conclusion by comparing the energy output of older galaxies and newer galaxies.
“Essentially the universe is curling up on the sofa and become an old universe,” Jochen Liske from the University of Hamburg, who was involved in the research, told IFLScience. “The universe is getting darker and darker. It is becoming a very cold and dark place.”
Above is a visualized fly-through of the galaxies in the GAMA project. Will Parr, Dr. Mark Swinbank and Dr. Peder Norberg (Durham University)/SDSS/GAMA/Ogden Trust/STFC/Royal Society.
This research, presented today at the International Astronomical Union XXIX General Assembly in Honolulu, Hawaii, is slightly different from another theory for the end of the universe known as heat death. That states that as the expansion of the universe continues to accelerate, things will become so spread out that they will no longer interact with each other. As Liske puts it, “the universe is dying multiple deaths.”
However, the researchers aren’t sure which fate will befall the universe first. “It depends on how big the acceleration of the universe is," said Liske. "That’s a question we haven’t quite answered. We don’t know what causes the accelerating expansion yet.”
But the heat death of the universe is expected to take many billions of years. It is likely that, before it occurs, the galaxies will have already run out of energy. And that’s a scenario that simply can’t be avoided. “We’re definitely going down this route,” said Liske. “If you wanted to go back, you would need a cosmic process that changed the universe, and erased huge density fluctuations. There’s no process we can think of that could do that.”
As mentioned, though, it’s not all bad news. It will likely be many billions of years until all the lights go out and no stars are visible from Earth. And before that takes place, Earth will be consumed by the Sun in a few billion years when it expands into a red giant prior to its death, leaving our planet a barren and inhospitable world devoid of life.