Silent Acorns

Suppose for a moment that there will be a crunch.

Does this imply that nothing can escape, even light, and that we are inside of a black hole?

If so, this would mean that we can never get outside or see outside, but energy could come in. You could then think of our universe as one of many black holes in a larger universe. Now, since black holes have mass they will be attracted to each other by gravity. I have to wonder what would happen if two giant black holes collided. It has been mathematically proven that from the outside you would just get one big black hole. But relativity breaks down inside a black hole, so we can't predict what will happen inside.

I like to think that maybe our Universe (i.e. what we see around us) is the result of such a collision. The "Big Bang" would be the moment of collision, and the current expansion would be "hiccup" before everything settles down in the crunch.

I realize that this is just a wild little idea running around in my head, but I'm interested to know if it is consisent with the known laws of physics.

tronvillain

If you define "Big Crunch" as the complete collapse of all matter and energy in the universe into a single singularity, then by definition nothing can escape. Does this imply that we are "inside" of a black hole? No. You yourself said "we can't predict what will happen inside" so no observation we could make about our universe would serve as evidence for our being inside.

crocodile deathroll

I believed it once, but I think in the light of the universe which is observed ot not only not slowing down enough to recollapse into a big crunch by it is accellerating. Things are looking pretty grim for the big crunch theory

tronvillain

True, but Silent Acorns said "Suppose for a moment that there will be a crunch." I doubt that there actually will be one.

Defiant Heretic

That is correct. Recent observations have indicated that the expansion of the universe is actually speeding up.

Reference: Scientific American: Volume 12, Number 2
The Once and Future Cosmos
(I can't find the damn thing at their site, but my issue says on the cover that it'll be on the shelves until Dec 31. I did find <a href="http://www.sciam.com/article.cfm?colID=2&articleID=000F0F7A-B895-1DC9-AF71809EC588EEDF" target="_blank">this article</a>, though. Irrelevant, but interesting.)

eh

Keep in mind that if there is some kind of quintessence responsible for the expansion to be speeding up, then it may eventually have the reverse effect and pull everything into a crunch. No one knows whether this field, or some kind of other concept (dark energy) can explain the cosmological constant.

Answerer

Well, I don't think that the universe will accelerate on and on forever, at some points, I feel that it must stop.

Gringo

One of Sagan's books, maybe Cosmos, briefly discussed one possibility of the big crunch. That possibility was that we might live our lives over and over again as the universe fluctuates between a big bang and a big crunch. That would suck for creatures who only knew misery, like a bird being eaten as he hatches from an egg.

eh

Are you sure Sagan took such an idea seriously?

Kharakov

edited to remove post

[ November 16, 2002: Message edited by: Kharakov ]</p>