If the Big Bang created space itself how can there be a concept of the realm it's in?

cdux

How can there be a concept of it expanding when there is no realm existing for it to expand into?
Unless, there is that realm and space is only another new medium our Universe can exist in.

HallsofIvy

No one has said "space" is expanding. It is the distance between stars that is expanding.

cdux

That's news to me. I thought it was consensus that space and time were created at the Big Bang and expanded from there on.

ImaLooser

I don't mean to be snide, but my answer is: why not? True, it is a kind of weird concept.

cdux

Yes, why not, indeed, but my point is that even if the medium of what we're talking about is expanding (even if it's not the consesus opinion apparently, let's assume it is) then its expansion should have a medium to expand into.

Consider this:

You reach the end of the Universe and you hit a wall.

What is holding the wall?

What is that force behind that wall?

Or do you fall into some kind of destructive event horizon? Why? What is there?

It's either another medium or an incomplete collapsing theory in that sense.

Number Nine

There is no evidence that the Universe has any such "wall", so there's no problem.

cdux

I guess my point is that at the end of the day any finite universe theory has the problem of explaining what limits its infinity. Where does your universe end and what stops it and what happens when I reach that end?

Because if I reach that end and something stops me or something puts me into a loop, or anything actually, it means another universal medium is holding me back. i.e. your universe is not finite. It has boundaries. And the boundaries require an external universal medium.

Only an infinite universe would explain it.

Mordred

Not necessarily the term nothing does not reside in quantum mechanics. Quantum fluctuations pervade nothing lol. this article may have some of the answers you seek.
PS its not the best article I've seen but at least it provides some direction for answers.

http://wiki.answers.com/Q/Where_did_...Bang_come_from

Drakkith

Or a finite universe that loops back on itself. There is no wall, no boundary. Things just keep expanding. And perhaps a key point here is that the standard model of cosmology does NOT require that the universe be expanding into anything. Per the math it simply doesn't matter. There may or may not be anything else outside our universe, and there may not even be any way to ever tell if there is. But the math that the model is based on doesn't care.

bcrowell

Either interpretation is OK. They're not empirically distinguishable statements.

cdux

If it's looped, what defines the boundaries of its shape? There must be something there that defines the "non part of the universe". How could there be nothing if to have nothing you have to have the absence of non nothing?

Drakkith

What's outside the universe? I could tell you nothing, or I could say that such a question may not even make sense. Like asking what flavor is blue. Or asking what the volume of 1 second is. Just because there may not be a boundary to the universe, or we may be expanding without expanding INTO anything does not mean that "something" exists "outside" of the universe. To the very best of our knowledge the universe, quite literally, is everything that exists. Asking what exists outside of the universe...is simply nonsensical.

The universe does NOT need to obey our logic. It has proven so time and time again in the past and it will probably continue to do so.

skydivephil

Surely the phrase outside requires there to be some space. If Im outside my house I Im in a location in space that is beyond the boundary of my house. So therefore isnt it right to say the very phrase "outside" implies a location in space? hence its hard to see how the phrase "outside of space" makes any sense.

Mordred

I like that analogy skydive nice simple and self explainitary

cdux

I'm not asking what flavour is blue. I'm asking what color is non-white.

Which come to think of it, I just made your argument, since black could be considered the absence of light and color just a mundane human concept.

However, "color" (universe) would have to pass through a medium to be a color. Is that exotic medium nothing?

For which one could return to me and say "But you just said color is a mundane concept", ah, yes, but here's a catch, we accept that "color"(universe) in consensus physics hence is it not of substance? And if not, is reality nothing?

Mordred

The simple fact is there is no evidence of a multiverse scenario. We simply do not know if we are one spacetime universe or one of several or an infinite number. There are countless multi verse theorem literature on the web several are posted. Truthfully we don't even know of our own universe is finite or infinite. These are concepts still being studied to determine an answer. Mathematically many of the proposed models make sense however they all have various problems. The big bang best describes the expansion of our own universe. Until we can find evidence outside of our own the question you asked is one that cannot be resolved, only theorized

cdux

A good theoretical reasoning is that if we can't find an actual reason governing the nature of fundamental properties, then it's logical to assume there may be an infinite or very large number of different sets of laws and it just happens to be in one that works this way.

On the other hand though, it gets tricky when one has to assume the properties of the medium it holds them together. Doesn't it have fundamental properties?

And then what do we get, infinite multiverses?

And then infinite multi-multi-verses?

Perhaps.


Then we'd have to explain "why is there infinity?".

Is the actual (whole)universe just the existence of infinity?

But again, "why?".

Or, "How?".