Khaled Younes |
Thursday, August 11, 2022 – 07:26 PM
Astronomers are looking at how the universe will end, since anything that has a beginning must have an end. Every living being has the moment of death and the departure of life.. Stars and planets also disappear and disappear.. Thus, from the smallest germ to the largest galaxy, death “lurks” waiting for the moment. crucial; Even if the time scales are, from a cosmological perspective, too big to really understand.
In the end, even the universe itself must come to an end – when the last light comes out, and cold, dense masses of dead stars remain.
This is, at least, the case under current cosmological models. What if our universe did not die a cold death, but collapsed, inflated again, and collapsed again and again, like a giant cosmic lung? It’s not an entirely widely accepted theory, but for some cosmologists, our universe could be just one in a long chain of birth, death and rebirth that has no beginning or end – not a big bang, but a big bounce.
And now the physicists have shown that the latest iteration of the Big Bounce hypothesis – which solved important problems with previous iterations – still has significant limitations.
Physicist Will Kenny, from the University at Buffalo, said: “People have proposed bounce universes to make the universe infinite in the past, but what we’re showing is that one of the newer types of these models doesn’t work. And in this new type of model, which addresses entropy problems, even if the universe had courses, it must still have a beginning.”, according to “Russia Today”.
Currently, the most plausible model of our universe sees it emerging from a point of origin called the singularity. About 13.8 billion years ago the universe as we know it started expanding out of a very dense chunk of space and time for some reason.
Unfortunately, the models that support the “big bang” explanation don’t have much to say about what such a singularity might look like.
Alternatively, the Big Bounce hypothesis could avoid the singularity issue by eliminating it altogether. Instead, the collapsing universe would bounce back before it reached such a moment to break the pattern.
However, the hypothesis was not without its own problems. An infinite “rebound” universe must have infinite entropy, the measure of chaos in the universe. And if the Big Bang was just one of an eternal series of explosions, then the universe must have been really high; However it was not. In fact, if the universe was high up in the universe at the Big Bang, it would not exist as we know it.
And in 2019, Big Bounce took a hiatus, with the publication of a revised model containing a solution to this significant hurdle that has held back the hypothesis for decades. The researchers found that the expansion of the universe with each cycle weakens the entropy enough to return the universe to its original state before the next bounce.
This was a huge deal, apparently putting the “Great Bounce” back on the table as a plausible cosmological model; But now, other scientists have made a new hole in the revised model.
Kenny and his colleague, physicist Nina Stein, also from the University of Buffalo, performed a series of calculations, and found that the cyclic universe could not extend infinitely into the past.
The team notes that their work does not apply to physicist Roger Penrose’s model of the cyclic universe, called cyclic correspondence cosmology. According to his version of a recurring universe, each cycle expands infinitely with no period of contraction. These are very complex things, and require more twitching.
However, for now, it appears that at least the big bounce will require more thought to remain viable.
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