Scientists have a fairly good idea of how our universe began: according to the Big Bang theoryAn infinitely small dense point quickly widened 13.8 billion years ago, and the universe has experienced accelerated expansion since. However, trying to imagine where our universe could then go, or even how and when it could possibly end, is always fiercely debated.
“In physics, we can only trust our ideas and theories when we collect the data that test and confirm them”, ” Nemanja KaloperProfessor of physics at the University of California, told Live Science in an email. “(But) in cosmology which is notoriously difficult because the experiences are passive – we cannot recreate the universe to see how things go and improve the sets of data at will.”
So, exactly when will the universe end? It depends on the theory you find most convincing. Two of the main head theories are called The Big Freeze and the Big Crunch.
In relation: Could a black hole devour the universe?
The big frost
For Henry TyeProfessor Emeritus of Physics at Cornell University, the most likely scenario is “Freeze. “”
“This is what is already going on right now,” said Tye. “The expansion of the universe will become faster and will continue for 100 billion years, a Billion of years or forever. There is no final point.”
A cosmological model that explains this expansion is the idea that our universe extends to an area called “guardian space”, which is part of the space with an intrinsic positive energy which can help push the universe to the outside. This means that the universe would not necessarily end, but it would not stay either. As its name suggests, the big frost would dilute energy in the universe by so much that any form of activity – like the burn of the stars or the barattage of black holes – would end. This is what physicists call “thermal death of the universe”.
The great crunch
However, it is also possible that this positive space of Sitter can one day decompose in negative energy, which would reverse the direction of the universe.
“It would mean (would mean) that the universe develops a little before reaching a maximum, then turns around,” Antonio PadillaProfessor of physics at the University of Nottingham in the United Kingdom, told Live Science in an email. “Such a universe would end up a crunch.”
This “big crunch” would essentially reverse the expansion of the big bang and would erase our universe. The frightening thing about this scenario, said Tye, is that it could already occur in pockets of the universe, but it would be largely undetectable because the evidence of these areas of space would be erased.
A few recent models predicted that a big crunch, motivated by dark energy – the mysterious force resulting in the accelerated expansion of the universe – could start in 100 billion years. In particular, this chronology was determined by studying a theoretical model of a type of dynamic dark matter called “quintessence”. Conversely, in a paper, Padilla contributed to in 2021He found that the universe has at least even a trillion of years – which, according to him, was the shortest part of the estimates. This determination was made using the ideas of string theoryWho imagines particles as tiny strings 1 dimension instead of points.
Even then, the universe might not be ready to completely stop existing. Some scientists believe that a big crunch can be part of a more important cycle of expansion and contraction that took place in the early universe called A big rebound. In this idea, the universe “started” with a rapid expansion (that is to say a big bang) and would develop for a while before finally collapsing under the conditions necessary for another Big Bang.
As for what theory is correct, it is difficult to say with total certainty, said Padilla.
“It is difficult to predict the distant future,” he said. “My opinion is that observations can only take us so far here because of the very nature of what we are dealing with.”
Even if none of these theories is correct, there can still be an expiration date when the whole regular question of the universe – stars, galaxies and even leftovers of dead stars, such as black holes – will simply stop being. Due to a type of spontaneous influence predicted by Stephen Hawking, everything in the universe could slowly evaporate towards nothing, a study in 2025 published in the Journal of Cosmology and Astroparticle Physics suggest. The time proposed for this total evaporation is 1 Quinvigintillion years – It’s 1 followed by 78 zeros, or 1078.
According to Tye, there is no evidence that could fully prove a theory on the fate of the universe. Instead, cosmologists must improve the existing models of our universe and extrapolate them endlessly. Win a better understanding of complicated subjects like dark energy And string theory is a way in which scientists can better predict our universe.