Naked Science Forum

Non Life Sciences => Physics, Astronomy & Cosmology => Topic started by: @theblob1 on 10/03/2011 15:30:03

Title: What is the universe expanding into?
Post by: @theblob1 on 10/03/2011 15:30:03
@theblob1 asked the Naked Scientists:
   
If the universe is constantly expanding, what is it expanding into?

What do you think?
Title: What is the universe expanding into?
Post by: Soul Surfer on 10/03/2011 17:25:55
Most probably a quantum mechanical vacuum just like (or very similar to) the sort of quantum mechanical vacuum we have in our universe but it is very unlikely that it will ever be possible to prove this experimentally.  It could only be proved by inference and an accepted version of a substantially complete theory of everything that explains fully the origin and end of our universe.

However there are some ideas where it may be detectable.

If our universe WAS inside a black hole in another universe a small amount of material from outside could be falling into it and accelerating to vastly high energies in the external gravitational field (these could be similar to high energy cosmic rays that we do detect and cannot fully explain yet).  If the originating particles in these could be detected and their properties measured precisely, we might find that they were slightly different from the particles in our universe.  Now that would be interesting!
Title: What is the universe expanding into?
Post by: yor_on on 11/03/2011 00:23:26
I don't think it is expanding into anything 'existing'. If anything, I think the expansion makes it exist :) where it 'didn't' before. And that said I will now join a hermit tribe to meditate :)

Physics huh :)
Title: What is the universe expanding into?
Post by: Bill S on 11/03/2011 02:59:43
If our Universe is all there is, then I think yor_on must be right; there's nothing out there; in fact there is no "out there".  On the other hand if there is a wider cosmos beyond the Universe there is something there, but finding out what it is could be quite a challenge.
Title: What is the universe expanding into?
Post by: abacus9900 on 12/03/2011 21:33:16
Quote from: yor_on on 11/03/2011 00:23:26
I don't think it is expanding into anything 'existing'. If anything, I think the expansion makes it exist :) where it 'didn't' before. And that said I will now join a hermit tribe to meditate :)

Physics huh :)

This is a bit puzzling. It must mean the universe is literally 'creating' something from nothing! So, does that go against all that is scientific? It's almost the 'Genesis' version of things.
Title: What is the universe expanding into?
Post by: grizelda on 13/03/2011 08:36:16
There is no evidence that the universe "needs" anything outside it to explain it: it seems to work well without any interference. In fact, any miraculous "help" it got would probably blow it up and we haven't seen that either.
Title: What is the universe expanding into?
Post by: abacus9900 on 13/03/2011 10:24:26
Quote from: grizelda on 13/03/2011 08:36:16
There is no evidence that the universe "needs" anything outside it to explain it: it seems to work well without any interference. In fact, any miraculous "help" it got would probably blow it up and we haven't seen that either.


But surely, 'existing' and 'non-existing' are mutually exclusive, aren't they?
Title: What is the universe expanding into?
Post by: grizelda on 13/03/2011 21:03:32
Yes, if time begins when the universe is created then there is no time when it doesn't exist. Much simpler than a "time before time" or a "space outside of space".
Title: What is the universe expanding into?
Post by: Bill S on 14/03/2011 02:03:18
Quote
Yes, if time begins when the universe is created then there is no time when it doesn't exist. Much simpler than a "time before time" or a "space outside of space".

Simpler, only if you don't think too much about it.  For example:
If there is no time outside the Universe, does this mean the Universe is eternal? 
If the universe is eternal, how could it have had a beginning?
If the Universe is not eternal, how could something come from nothing?

This is just a start where questions are concerned.


















Title: What is the universe expanding into?
Post by: Bill S on 14/03/2011 02:05:11
I didn't mean to take up all that space, honest.  [:I]
Title: What is the universe expanding into?
Post by: grizelda on 14/03/2011 02:38:21
It's okay, the space can be recycled, as well as the time. Probably it's only mathematical logic that is eternal, and the universe is something that that logic demands.
Title: What is the universe expanding into?
Post by: Novacaine on 24/03/2011 15:52:04
We know that universe is expanding. So, does that mean, new created space comes from nothing? We have been teached that nothing can vanish or can exist from nothing. Just change its form. And we know that the emptiness is not actually empty. There is something we dont know yet much about in empty space. Is it possible that there is still a reaction between the universe we know and some sort of energy beyond it? And via this process new part of space, which wasnt there before, comes to our reality constantly. I hope I could made my point =)
Title: What is the universe expanding into?
Post by: Phractality on 25/03/2011 07:45:15
Space expands, but the universe is infinte. The universe can't get bigger, so it is not expanding. New space is being created everywhere, all the time; this increases the distance between the most distant objects, but gravity and other forces keep objects at a fixed size. I'm afraid I can't explain HOW space expands without "evangelizing".