Expanding equally everywhere.

And, thus, a center.

I came across this idea on Wikipedia. Not sure I buy it, but it's interesting nonetheless:

http://en.wikipedia.org/wiki/Doughnut_theory_of_the_universe

The big bang wasn't an explosion in space, it was an explosion of space. Therefore a "center" could exist at any vantage point as the universe expands uniformly.

I know there are theories concerning multiverses, but even if ours is indeed the only universe, I would love to know what sort of void, if any, separates our universe from the unknown - a "space beyond space," if you will.

Space operates on a few basic rules, including the nonstop production of virtual particle-antiparticle pairs that usually annihilate each other instantly. Space expands in all directions, but these few rules are what makes space what it is.

If it's not "inside" something else, size becomes meaningless. Size is only relevant in terms of relation to other sizes.

It is space itself that expands evenly. Imagine a balloon with black dots all over it, if it is blown up all the black dots expand evenly at the same rate uniformly.

...and the balloon model explains the apparent redshifting of most galaxies away from each other.

But even as the distance between the black dots on the balloon is increasing, the balloon itself still appears to enclose a volume. An ant walking on the surface of the balloon may not perceive that it has a center, but it does exist.

Could the curvature of space itself play into whether or not space has any true center, perhaps?

and quite possibly more than that. Think of time as an axis perpendicular to the other three axes in the three dimensions we see ordinarily and you start to get the point.

We're looking backwards in time as well as in three dimensions when we look out at our corner of the universe.

Also, the big bang didn't exist within a volume. It created that volume and is still creating it if the theory of increasing inflation is correct. We know of nothing that says that volume has to be perfectly symmetrical.

Seriously, though, the latest gravity wave results seem to validate the hyperinflation theory of Alan Guth and beyond that, the eternal inflation multiverse theory of Andrei Linde, which posits that the big bang and our universe is really only part of an eternal series of branching, iterating, fractal multiverses constantly spawning or budding new universes off of themselves.

I don't pretend to fucking understand it, but it sounds cool.

http://blogs.scientificamerican.com/observations/2014/03/17/andrei-linde-learns-his-big-bang-theory-is-true-video/

http://www.slate.com/blogs/the_slatest/2014/03/18/andrei_linde_and_chaotic_inflation_theory_stanford_professor_s_theory_proven.html

http://en.wikipedia.org/wiki/Eternal_inflation

Lastly, I strongly recommend everyone in particular try to read this. I think this may be the whole package:


http://www.mukto-mona.com/science/physics/Inflation_lself_prod_inde.pdf

But I appreciate the links! Saving the PDF to read in detail later.

It's fascinating stuff. From an aesthetic perspective, I see fractals everywhere in the natural world, it would make sense to me that the Universe or Multiverse would arrange along those lines, too. Also, it makes sense to me, grok-wise, with the question "what creates universes" a logical answer to my mind is, "other universes".

Things in nature just seem to work that way.

Also, as a general point, infinity makes "sense" to me more than anything finite. Because if you have something finite, then there has to be a boundary, whether that is in space, or time, or both, and then what is beyond that boundary?

Hadnt seen any of those before. Awesome mandelbrot zoom.

but its all been scrubbed from YouTube recently (gee, I wonder why...).

The galaxies were drawn on the 2D surface of a baloon. As the baloon was blown up (in 3 dimensions) the 2D surface expanded and the galaxies receded from each other. There is no 'center' in the 2D sense; you have to add the extra dimension to find the center.

Now take the above and add '1' to all the dimensions and you have an explanation of 3D spacetime.

Another way of putting it is that even if space isn't infinite, it can be un-bounded (no edges) the way a 2D surface of a sphere is un-bounded.

That is where your conceptual flaw is. The analogy I've found most useful is to consider how a 2D being would perceive the surface of a balloon. The being might insist that the surface has a "center" on the 2D surface because all 2D surfaces he was familiar with have centers but he would be wrong. If the balloon were blowing up then all points on it would appear to be receding from him/her.

Our universe is described by General Relativity to be 4 Dimensional. This puts the "center" of the universe in the dimension of time not space.

...even though I've heard the balloon analogy before, I never really considered time to be a "center." But that is a most interesting thought, which I will try to mull over tonight over some General Tso's chicken.

If I don't walk out the front door tomorrow morning, you may safely assume my brain has imploded.

Because 3 space is likely not positively curved. But yeah, time = 0 at the Big Bang as the center works.

When you ask "what is space expanding into" I have a harder time conceptualizing that one. I've thought about this for many years so it gets easier after you've built several analogies for the mathematical description.

Good luck! I love thinking about this stuff.