Big Bounce vs Big Bang

[Alex K]

The article is not about our universe recontracting but rather our big bang actually being the result of a previous contraction. I don't think it would necessarily play out exactly the same way as its past mirror version, but since we don't know where quantum randomness really comes from, I don't think there is any way to say for sure.

So there must be non causality in order for it to not play out the same as its mirror past?

Non-causality (or let's say, non-deterministic quantum physics) is one thing that would keep it from playing out identically, but it isn't the only possibility. There could simply be some accidental asymmetry between the ends of the bounce. We know that the fundamental laws of physics are not exactly Time-Reversal-Invariant (as evidenced by the asymmetric decays of K-Mesons, D-Mesons and B-Mesons), so that isn't a stretch either. I'd say all things considered, it seems unlikely that it would be an exact mirror image.

[chimp3]

I think skeptics and theists are all going to have fun with the Big Bounce theory. It is rich in comic potential.

[Czechlervitz30]

I haven't read this article yet, sorry. But if this universe contracts and bounces back would the universe play out the exact same when bouncing back?

Well, according to the article the Big Bounce theory was suggested in the early 1900s, but the scientists haven't been able to prove it until recently. The universe right now is expanding. It is also accelerating in expansion. It is not contracting. I don't know the laws that govern whether or not it will stop expanding and then contract. It is going to rip apart according to the another article I found. I doubt the same things would happen again and again like in the movie Groundhog's Day.

On a funnier note: Since we have the tv show The Big Bang Theory, I think there should be a new show called The Big Bounce Theory with a renewed version of nerd factor or an updated set of science minded college kids with a hotter Penny(hot girl).

[Alex K]

I haven't read this article yet, sorry. But if this universe contracts and bounces back would the universe play out the exact same when bouncing back?

Well, according to the article the Big Bounce theory was suggested in the early 1900s, but the scientists haven't been able to prove it until recently. The universe right now is expanding. It is also accelerating in expansion. It is not contracting. I don't know the laws that govern whether or not it will stop expanding and

It still isn't proven. To "prove" it, bounce scenarios would have to provide observable phenomena distinct from inflation that are visible in the microwave background. If there are such predictions, they haven't been observed yet. What we have is a proof of principle that big bounce has a chance of working mathematically, at least in a simplified version of reality. The big bounce we discuss here is also not the same as a cyclical universe that recollapses again and again. Turok's paper on which the article is based only concerns the nature of the big *** in our past and whether it could have come from a previous collapse if I understand it correctly.

Currently there is no evidence that dark energy is anything other than a cosmological constant, and a cosmo constant by itself leads to eternal exponential expansion. But - dark energy could come from something more complicated such as quintessence models, and in those the dark energy can in principle become smaller, facilitating a recollapse - there is just no evidence for that as of today...

[Alex K]

+1 for the new big bounce sitcom. TBBT has started sucking many seasons ago...

[brewer]

Just watch the reruns in reverse order.

[Excited Penguin]

+1 for the new big bounce sitcom. TBBT has started sucking many seasons ago...

[LostLocke]

Just watch the reruns in reverse order.

No, don't. Or else you'll cause Sheldon to go on some long speech about how you're supposed to be disappointed in the order the writers meant you to be...

[LostLocke]

...and a cosmo constant by itself leads to eternal exponential expansion. ...

OK, my brain just rephrased that as a Deepity:
Cosmological constants lead to eternal exponential expansion.

[Alex K]

...and a cosmo constant by itself leads to eternal exponential expansion. ...

OK, my brain just rephrased that as a Deepity:
Cosmological constants lead to eternal exponential expansion.

Lol awesome, haha, it could come directly from Mr. Deepity himself, except that it has better alliterations and the advantage of being true!