Will the universe finish in a bang or a whimper? A pair of theoretical physicists have proposed a 3rd path: maybe the universe won’t ever finish.
In a research that makes an attempt to outline the character of dark energy — a mysterious phenomenon considered inflicting the universe to develop quicker and quicker each second — the physicists discover that cosmic enlargement is not all the time a given.
Somewhat, they write, darkish vitality might periodically “change” on and off, typically rising the cosmos, typically shrinking it down till the circumstances are proper for a brand new Big Bang to happen — and for a brand new universe to be born.
Associated: What is the Big Bang Theory?
The good escape
Our universe is at present experiencing a phase of runaway enlargement: The cosmos is getting larger quicker with each passing second. Cosmologists don’t perceive the reason for this acceleration, which they title dark energy. If this acceleration persists, then our universe will finally develop into oblivion, with all matter and radiation torn aside.
This would not be the primary interval of runaway progress. Within the earliest moments of the Large Bang, the energies and densities had been so excessive that present physics can’t cope — it predicts a singularity, a degree of infinite density the place the maths breaks down. After that, the universe skilled a interval of extremely speedy enlargement often called inflation, which can be poorly understood.
Astronomers have lengthy questioned if these two phases of accelerated enlargement — one within the earliest moments of the Large Bang and one within the current epoch — are linked to one another, and whether or not an entity that drives each of them avoids the issue of the large bang singularity.
Dynamical demons
To reply that, a pair of theoretical physicists revealed a research Feb. 7 within the preprint database arXiv (opens in new tab) which examined a mannequin of the universe the place darkish vitality has all the time performed a task. Earlier analysis modeled darkish vitality “switching on” at numerous instances to drive cosmic enlargement, however the brand new analysis proposes a extra practical mannequin that features matter and radiation.
They wished to see if darkish vitality can keep away from a Large Bang singularity, drive inflation, and speed up the late universe. To keep away from that preliminary singularity, the universe cannot start from a degree of infinite density. As an alternative, the universe we reside in must be one in an infinite sequence of repeated “Large Bounces.”
On this state of affairs, darkish vitality drives the universe till it reaches a sure dimension. However then the darkish vitality transforms itself, forcing the universe to contract. The cosmos then suffers an enormous crunch, however proper earlier than reaching a state of infinite density, darkish vitality turns round once more, driving a interval of extremely speedy inflation and beginning the cycle anew.
A finely tuned mechanism
The researchers discovered a mannequin of darkish vitality that carried out the trifecta. However crucially, matter and radiation couldn’t be current within the extraordinarily early universe, in any other case they spoiled inflation. As an alternative, matter and radiation needed to seem simply after inflation, as a portion of the darkish vitality decayed away, flooding the universe with mild and matter.
Whereas initially profitable, the researchers weren’t capable of finding a generic class of darkish vitality fashions that would all the time result in the identical outcomes. As an alternative, they needed to artificially put in a smaller worth for the present-day accelerated enlargement than quantum mechanics predicts in an effort to get the precise proper final result.
Nevertheless, this new analysis does level in a promising route, offering a viable platform for additional exploring fashions like this. People usually are not essentially destined to reside in a chilly, empty cosmos, as a result of darkish vitality would possibly behave in a different way within the far future. Solely continued analysis will uncover our final destiny.
Initially revealed on LiveScience.
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