Is it likely that a Big Crunch would restart the universe?

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Ann
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Is it likely that a Big Crunch would restart the universe?

Post by Ann » Sat Jul 30, 2011 7:07 pm

As I wrote in http://asterisk.apod.com/viewtopic.php?f=8&t=24589, I abhor the idea of a Big Crunch. Of course, the demise of the entire universe can never be an uplifting topic, no matter how you look at it. For all of that, however, each of us may actually prefer some ways of bringing about the ultimate obliteration of the everythingness to other versions of the ultimate destruction.
Click to play embedded YouTube video.
Personally I'm a claustrophobiac, which is probably why I feel such an unspeakable loathing of the very concept of the Big Crunch. But many others, not least many other astronomers, seem to want a Big Crunch to happen. Surely they can't be agoraphobiacs all of them?

Don't get me wrong. I'm not suggesting, of course, that any astronomers want the universe to die, as such. Rather, they are just convinced that the eventual demise of the universe is an unavoidable thing, and then prefer some ways for the universe to go over other ways to bring about the ultimate good-bye. And the Big Crunch seems to be by far the favorite way universe-killing mechanism for at least some astronomers.

But what is it about the Big Crunch that seems to make many astronomer think of it as their favorite mechanism for the universe to kill itself? I can think of a few possibilities:


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1) Symmetry. The Big Crunch can be seen as a sort of mirror image of the Big Bang. The universe was born in the fireball of the Big Bang, and it will die in the fireball of the Big Crunch. There is a beautiful symmetry to this, which probably appeals to laypersons as well as to professional astronomers.


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2) A semi-solution of the pesky dark energy problem. If dark energy, which frustrates astronomers by refusing to be understood by them, suddenly reverses its "charge" or "polarity" so that it becomes an attractive instead of a repulsive force, then dark energy doesn't go away but its pesky repulsiveness does, and we can sort of forget about it.













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3) Rebirth. The rebirth scenario is almost certainly the most attractive promise that seems to be linked to a Big Crunch death of the universe. The idea is that the Big Crunch will generate so much energy that this energy must be projected outward again in a super-sized Bounce and a regeneration of the entire universe out of the ashes of its own self.







But, Chris, Art, bystander and others who may feel inclined to answer, how likely is the rebirth scenario?


How probable is a Big Crunch in the first place, judging by what the best scientific research can say about it?

How likely is it that a Big Crunch would generate a Big Bounce?


How likely is it that, assuming that new universes are born in a multiverse, the Big Crunch death of a previous universe is the best way to generate a new universe?


If a Big Crunch death of our universe would really lead to a Big Bounce and to the birth of a new universe, how likely is it that this new universe would resemble our own?



What, if anything, is known about these things?
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Do astronomers who chase the Big Crunch and the Big Bounce have more reasons for their belief than the quest for symmetry, the battle against dark energy and the heroic struggle to give our universe at least nine lives?


























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alter-ego
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Re: Is it likely that a Big Crunch would restart the univers

Post by alter-ego » Sun Jul 31, 2011 8:26 pm

Ann wrote: What, if anything, is known about these things?
Nothing is known. Symmetry is an attractive concept, but asymmetry may ultimately be the primary reason for our existence.
A pessimist is nothing more than an experienced optimist

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Re: Is it likely that a Big Crunch would restart the univers

Post by Ann » Mon Aug 01, 2011 1:39 pm

Thanks for your input, alter-ego! Much appreciated.

EDIT: I've just watched a British TV program about how the interplay between order and chaos, and the working of self-replicating systems which however are constantly affected by "butterly effects", mean that the universe is never perfectly predictable, and never perfectly symmetrical.

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