Will the universe end with a bang or a whimper? A pair of theoretical physicists have proposed a third path: perhaps the universe will never end.
In a study trying to determine the nature of dark energy – A mysterious phenomenon thought to be causing the universe to expand faster and faster every moment – Physicists have found that cosmic expansion isn’t always a given. Instead, they write, dark energy may “turn on” and stop periodically, sometimes growing the universe, sometimes shrinking it until conditions are right for a new emergence. the great explosion For it to happen – for a new world to be born.
The Great Escape
Our world is currently going through a phase of runaway expansion: the universe is getting faster and faster with each passing moment. Cosmologists do not understand what is causing this acceleration, which they call dark energy. If this acceleration continues, our universe will eventually expand into oblivion, with all matter and radiation shredded.
This will not be the first period of runaway growth. In the first moments of the Big Bang, the energies and densities were so intense that current physics can’t cope—it predicts a singularity, the point of infinite density where the math breaks down. After that, the universe went through a period of incredibly rapid expansion known as inflation, which is also poorly understood.
Astronomers have long wondered if these two phases of accelerating expansion—one in the early moments of the Big Bang and the other in the current era—were linked, and whether the entity driving both avoided the problem of the Big Bang singularity.
To answer that, a pair of theoretical physicists published a study Feb. 7 in Database Preprint arXiv (Opens in a new tab) which examined a model of the universe in which dark energy always played a role. Previous research has modeled dark energy “switching” at different times to drive the cosmic expansion, but the new research proposes a more realistic model that includes matter and radiation.
They wanted to see if dark energy could evade the Big Bang singularity, drive inflation, and speed up the late universe. To avoid this initial singularity, the universe cannot start from a point of infinite density. Instead, the universe we live in should be one in an infinite series of recurring “big bounces”.
In this scenario, dark energy drives the universe until it reaches a certain size. But dark energy then transforms itself, forcing the universe to contract. The universe then suffers a major crisis, but before it reaches a state of infinite density, dark energy turns around again, triggering a period of incredibly rapid inflation and the cycle starting over again.
Precisely tuned mechanism
Researchers have found a dark energy model that leads to a trifecta. But crucially, matter and radiation could not have existed in the very early universe, or they would have messed up inflation. Instead, matter and radiation had to appear just after inflation, as part of the dark energy vanished, flooding the universe with light and matter.
While the researchers were successful at first, they couldn’t find a general class of dark energy models that could always lead to the same results. Instead, they had to artificially set a smaller value for the current’s accelerated expansion than quantum mechanics predicts in order to get the exact correct result.
Nevertheless, this new research points in a promising direction, and provides a viable platform for further exploration of models like these. Humans don’t necessarily have to live in a cold, empty world, because dark energy may behave differently in the distant future. Only continued research will reveal our ultimate destiny.
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