Regarding the whole Big Bang theory.. If in fact the universe was created by a big explosion, every explosion has its borders, if this is true, what would be outside the area of the explosion that created the universe, since it is still expanding. Does anyone have any theories regarding this, or thoughts?

I guess the standard answer to this question goes something like this:

The Big Bang event did not have a boundary - put simply, the event created the dimensions it occupied as it happened. The question is similiar to the old philosophical argument regarding what exists "outside" the universe - since the entire universe was created by the big bang, it may help to visualise the event as an unfolding of an infinite space into three dimensions, rather than a fireball "Hollywood" explosion.

This hints at a wider problem - namely, the reliance on metaphor and imagery when describing events which do not necessarily conform to the physical laws as we understand them. Size, shape, distance, time - all these concepts were irrelevant (nonexistant?) at the moment of the Big Bang.

Anecdotally, I once had a friend who, when faced with the Big Bang, the concept of infinity, and particularly string theory, decreed that he could only understand them when drunk or stoned.

Duuuuude, physics *rocks*!

I'll try to put it into simpler terms. The universe, according to current theory, is infinite, yet finite.

Imagine, if you will, you're an ant. Someone takes a globe, cuts it in half, and sticks you on the South Pole. Then they put the two halves together and seal them. That ant (you) would be able to walk in the same direction infinitely. If it was dark, the ant would have no idea if it was passing where it had before, or if it had been following a straight line. Space is dark, all we, the layman. have to navigate by is a white point of light.

So the globe would be finite. From outside, we'd see just how small that little globe is. However, from the inside, it would be infinite, because the ant could wander forever and never realize it had been where it was while following the same direction.

EDIT: Forgot to add a point. What's beyond the universe? Ask the ant what's beyond the globe. We have no answer, and according to current theory, we won't. It may be that we're sitting in this little snowglobe that someone is watching thinking it's hilarios that these "intelligent" creatures keep wondering about life outside the snow globe. Obviously I don't believe in this particular scenario, but I hope you get the idea.

[Edited on 5-1-2004 by junglejake]

I understand that, yes. It was something I was thinking about the other day in my astronomy class when we were discussing the big bang theory, and just made me wonder if we had a boundry to the universe, if in fact it was an explosion. Thanks for the input =)

Regarding the whole Big Bang theory.. If in fact the universe was created by a big explosion, every explosion has its borders, if this is true, what would be outside the area of the explosion that created the universe, since it is still expanding. Does anyone have any theories regarding this, or thoughts?

The universe is finite. Outside of it, there is a larger "universe", different from the one we know. Outside of this larger universe, there is an even bigger one, and this may go on recursively for ever.

The truth is, we don't understand what lies beyond. We can't even speculate successfully. It might be that our universe is just a tiny particle in another universe, which is a tiny particle in yet another one etc.

Madness, eh ?

What makes you say the universe is finite?

I agree that we're a little short of objective evidence, but surely the recursive model is an arbitrary choice? Occam's Razor dictates that we select the simplest explanation which fits the facts we have - I would have to argue that leaves us with one infinite universe.

Well, one finite universe.. one infinite cosmos.... :-)

Anyway, the big bang theory does not really tell anything, what, where, when, why, how, or even if a bag happened at all. All we know is that the universe as we know it is expanding. so, we just reverse the flow and come up to a finite amount of space that exploded. Ok, that is the kindergarten answer, but sounds good.. :-)

We could not find the outside of the universe because, the light has not reached us yet. so, no viewable way to know. The light will reach us probably long after the earth or even our solar system have ended. So, since science has no way to come up with an answer, most just leave it alone and concentrate on the areas that we have a starting point. The universe and it is expanding. for now, we just have to leave that part up to pure speculation.