The "light barrier", and the known universe

[Greebo]

SO the other day the Better Half and I are watching some tv show - I think its "The Universe" or maybe 'Understanding" - I don't remember - and the topic is light. The speed of it, the ability to look back in time by looking further and further away in space, and they mentioned something interesting about how we ONLY know about the universe we can see.

So I remember something I saw, I think here, about how black holes have an upper limit beyond which they can't maintain stability (or something, my memory is really vague on this), and I get to wondering...

Ok the earth basically has a "sphere" around it that makes up a light boundary, of roughly what, 14.5 billion light years in radius, beyond which we cannot see. That doesn't mean nothing exists beyond the sphere, only that if it does, we have no way of knowing about it, due to the speed of light restriction of physics.

So I get to thinking - what if the universe is really far far bigger than we realize, and the area we can see is something like the ripples of a splash on a vast lake?

Is it possible - and more so - is it plausible - that the universe is actually so big, and the upper limit of black holes is so vast, that the big bang, to which we refer as "the beginning" was actually a relatively small event in the scale of the overall universe?

Imagine a lake on a calm day. It has some ripples, and at any time, you can see ripples on the surface coming from all directions.

Now throw a stone into the lake. Radiating out from the point where the stone lands, you see ripples. Inside the ripples, for a while, you see calm. The outward force of the ripples from the stone overwhelm the other ripples - for a while - but eventually ripples from beyond the radius of the stone's ripples make their way onto the patch you had earlier cleared.

Could the universe actually be like the lake and the stone falling like our big bang? Could the area of the universe which we can see be within the "ring of ripples"?

In other words...look at this line:

<-----------------[-------{-----------------------e----------------------x}----------------------------------------------------]----------------->

Imagine that x is the center of the ripples - the point in space at which the big bang occurred.

e is the earth

{ } is the edge of our light boundary, a radius on either side of earth of 14.5 billion light years

[ ] is the edge of the explosion of the big bang

< > are the actual outer edges of the universe (if they exist) - or perhaps just the borders of some arbitrarily defined portion of the universe - a subset (a massive one but a subset)...

In the above picture, representing known space today plus a bit more, the big bang occurred at x, 14.5 billion years ago. We're some distance from it, part of the explosion, moving outwards from the center, but we can only see so far, and the explosive effects go so much further beyond what we can see that we assume that the space between { and } is all there is, when in reality on the far sides of [ and ] are teeming, swarming galaxies moving in all kinds of directions, and [ and ] are pushing out against them, pushing back everything from the force of the explosion, even light.

Obviously, eventually [ and ] will lose strength and more material will start to filter in, but it's billions of light years beyond what we can see in this example.

So - is this at all remotely possible? Or would this be better served as a sci-fi premise?

Thanks in advance for entertaining this layman physicists silly notions

[Steve D'Ippolito]

I know that the theory claims space itself is expanding--there isn't a center of the universe where the big bang occured. Of course that's "reifying space" so that's probably bogus, BUT what if space is four dimensional and what we see is on the 3-D "surface" of the expanding 4-D hypersphere? The big bang in that case would have happened somewhere not anywhere in the universe as we see it today. (Imagine by analogy the surface of an expanding balloon; the entire universe we see is the surface of the balloon, expanding outwards from a center that quite literally isn't anywhere to be seen.)