# Before the big bang

1. Oct 14, 2009

### tanzanos

I have been thinking about how the universe came to be and this idea came to me:

Suppose space is comprised of parallel super dimensions (branes) and one contains a universe that is collapsing. As the universe nears a singularity; space will warp into an outward cone. If this cone touches an empty (no mater nor time) Brane (super dimension) then the oposite will occur as a big bang. The singularity will spill out into the empty super dimension. Could this be possible?

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2. Oct 14, 2009

### friend

Of course that begs the question of where did these extra dimensions and branes come from.

3. Oct 14, 2009

### tanzanos

Perhaps they are not even dimensions but areas that differ enough to cause such an effect?

4. Oct 14, 2009

### twofish-quant

Yes it's possible. Coming up with explanations of what happened before the big bang is quite easy, but it's so easy that I don't think it's very fun and challenging.....

Now for the hard part.......

What experiment or observation can you do to demonstrate that what you described *DIDN'T* happen. That's the hard part. The trouble with talking about things before the big bang is that you can make up just about anything.

I claim that the big bang was the result of giant multi-dimensional turtles sneezing. Try coming up with an experiment that shows that this *didn't* happen. It's quite difficult.

5. Oct 14, 2009

### DaveC426913

That would mean these "areas" have to have properties.

6. Oct 15, 2009

### tanzanos

Very true! One way to hypothesize is to reverse the big bang. The entropy that caused the singularity to expand into an universe must still be present and thus allow for a repetitive "death rebirth" situation.

7. Oct 20, 2009

### m115919h

I was thinking, isn't theoretically possible that the entire universe will eventually be pulled into a black hole. One black hole sucks in another black hole until everything is sucked in. Maybe at this point once everything is sucked in, that a "big bang" occurs? Is possible that the universe goes through cycles?

8. Oct 20, 2009

### DaveC426913

Yes and no.

In the closed model of the universe, gravity will stop the universe's expansion, reverse it and bring it back to a "Big Crunch". This would happen without any need for black holes.

Much reasearch is going into determining whether the universe is "closed", resulting in a Big Crunch, or open, resulting in an eternal expansion. The jury is still out.

9. Oct 20, 2009

### twofish-quant

The jury has reached a verdict. The universe is open and in fact it's accelerating.....

10. Oct 21, 2009

### DaveC426913

I could be mistaken, but I believe the current thinking is that it is merely probably open. Can you reference something that says otherwise?

11. Oct 21, 2009

### Ich

Open or not is not as relevant as it used to be. With DE, even a spatially closed universe could expand forever.

12. Oct 21, 2009

### twofish-quant

13. Oct 21, 2009

### DaveC426913

We're not talking about that kind of open/closed. By definition, a universe that will not collapse is an open universe, and a universe that will collapse is closed.

14. Oct 21, 2009

### Wallace

You're about 15 years (give or take) behind on the research. No one uses the terms 'open' and 'closed' anymore as Ich pointed out. The addition of DE into the model has made the terminology redundant and prone to confusion. You can still talk about postively or negatively curved, but the fate of the Universe is determined by the DE properties, and all the evidence very clearly shows that the Universe is accelerating and will not re-collapse.

There is a lot of research going on, but this question is done and dusted, at least until some drastic change in the model occurs.

Well yes, there is a formal error on the chance that the Universe will re-collapse, but if you take the current concordance model (with its errors) then a re-collapsing Universe is ruled out by a huge confidence margin. You can check the references provided by twofish-quant or read pretty much any cosmo papers written in the last decade.

Right, but as has been explained to you, that terminoloy is outdated and was only relevant when the whole model was described by $$H_0$$ and $$\Omega_m$$, which hasn't been the case for a long time.

15. Oct 21, 2009

### DaveC426913

OK, conceded. It might be better for someone else to explain to m11915h why the universe will not collapse into black holes.

16. Nov 9, 2009

### Skolon

If so, why this gays from NASA are saying "Thus, there is a direct link between the geometry of the universe and its fate." on this page? And they are talking about $$H_0$$.

17. Nov 9, 2009

### Wallace

I can't answer for what the folk who put that page together were trying to say. It does look a little disjointed, as though it was written by a committee..

The crucial point is in the first paragraph "If dark energy in fact plays a significant role in the evolution of the universe, then in all likelihood the universe will continue to expand forever." As far as the fate of the Universe is concerned, then dark energy it what matters, if indeed it exists. That second paragraph contradicts the first, so it is I agree, quite confusing! Go with the first paragraph, it is more descriptive of current theory and observations.

18. Nov 9, 2009

### George Jones

Staff Emeritus
Yes.
No, this is not the definition of "closed" and "open." The definitions refer to the topology of space (not spacetime). A universe is closed iff space (a hypersurface of simultaneity for cosmic time) is topologically compact.
I think these terms are still often used; for example, in Dodelson's book Modern Cosmology. As you note, there is no longer is a correspondence between the topology of space and whether the universe expends forever or eventually contracts. But this hasn't changed what is meant by "closed" and "open" universes.

19. Nov 10, 2009

### Skolon

Then what connection exist between matter and topology of Universe?

The topology is static or is modified by matter dynamics? Or maybe the dynamics of matter is dictated by topology?

20. Nov 11, 2009

### memphisp

ok in my infancy of cosmology knowledge i tend to have the same theory as the starter of this thread.

heres my thinking and someone correct me please, but if black holes have the power to break matter down into fundamental particles, if the BH exploded or emptied out into another universe, wouldnt the majority or the first atoms that were rebuilt be hydrogen??

if not, then what ultimately happens to a black hole? what form of matter is hawking radiation. because if it isnt matter then where is all of the matter the black hole sucked in??