BJ - A physicist once explained time to me in a way that made it all very simple to understand.
Someone once asked Steven Hawking what came before the Big Bang, and his answer was "What's more north than the North pole?". Basically, what he means is that, just as you cannot demarcate the "start" of a sphere, nor its end, even though it is not infinitely big, and just as it makes no sense to ask what's more northern than the north pole, you cannot mark the "start" or "end" of time. The question you're asking doesn't make sense.
Yes, I have heard this before.
But the question is: Is this really an explanation?
I think Hawking was just trying to get a bit of a handle on a puzzle that does not really have a clear solution.
Also, I think he was trying to get a handle on
3D curved space, not
time.
But I could be wrong.
A one dimensional creature can only move back and forth along a line. If he keeps moving forward, he would be suprised if he found himself back at his starting point. However, this is possible if the line is curved in on itself into a two dimensional circle.
A two dimensional creature can move back and forth, and left and right over a surface. If he keeps moving in the same direction, he would be suprised if he found himself back at his starting point. However this is possible if the surface is curved in on itself into a three dimensional sphere.
A three dimensional creature can move back and forth, and left and right, and up and down through space. If he keeps moving in the same direction, he would be suprised if he found himself back at his starting point. Apparently this would be possible if space is curved in on itself into a four dimensional "hypersphere".
It seems to be an answer to the question: what lies beyond the universe? The answer is: nothing lies beyond the universe. The universe is all there is. The explanation is to imagine the the 3D universe to be curved in on itself so that you can never actually leave it even if you travel in a straight line.
You will note, by analogy with the lesser dimensional examples, that
we need to posit a 4th spacial dimension into which our 3D universe curves: Just as the one dimensional creature does not see the second dimension into which his one dimensional world curves, and just as the two dimensional creature does not see the third dimension into which his two dimensional world curves,
we three dimensional creatures do not see the fourth dimension into which our three dimensional world curves.
So, we have an explanation for the universe being all there is, with nothing lying beyond it, but the explanation is at the expense of having to introduce a fourth dimension about which we have absolutely no clue and which becomes our new puzzle searching for a solution.
Therefore, I would say our 3D curved space explanation progresses our understanding a little, but I would not say we have solved the puzzle.
And I don't immediately see how
time fits into this scenario.
regards,
BillyJoe