Universal questions

[David90]

The universe started at the big bang and has been expanding ever since. Has it always expanded equally in all directions ? If so, this means the universe is spherical. Is it possible to locate the centre of the sphere, which would be the point at which the big bang occurred ? How far away is our sun from this central point, and how far away from the outermost reaches of the universe ? [ Nearest, furthest, average] What is the volume of the universe, and at what rate is this volume increasing ? What is it that is outside the universe, and into which the universe is expanding ?

[jake-the-peg]

This comes up with a great deal of regularity.

You are trying to impose a three dimension view on something which may very well not be 3D.

Firstly what is the Universe expanding into?

Well this presupposes that the Universe is like some bubble that is expanding into something like water.

The Universe may be more like a game of "Asteroids" and when you goo far enough in one direct you get back to where you started.

This would make it actually a 4 dimensional torus (bagel).

Remember that the Universe is not a big explosion into an empty void but the creation of space and time itself which are expanding.

In this context the idea of a centre is actually meaning less - a bit like medieval maps that placed Jerusalem at the "centre" of a flat Earth.

On the surface of a sphere any point is the centre. Likewise all points are at the centre of the Universe.

This is the reason, as every teenager knows, that despite what their parents say that they are really the centre of the Universe :c)

[heathfield]

One big problem is, David, that we can't see as far as the outer edge of our universe, so we have no way of working back to where the centre is.

[rov1200]

You would think mathematicians would have some answers. The big bang happened about 13 bn years ago. It should not be too difficult to determine the speed or acceleration away from the initial explosion. Then Newton's laws would give the distance travelled over that amount of time. Too simple?

[wildwood]

Everyone knows that Answerbank is the centre of the Universe!

[mibn2cweus]

It seems that we are at the centre of the small fraction of the overall universe that is within the range of what we are able to observe due to limitations such as those imposed by the speed of light, Doppler shift and inflation.

Is it conceivable that at some point near the edge of our observable universe there might now be an observer, similar to us viewing a universe similar to the one we see, pondering the possibility of our existence at some point on the edge of the sphere of their observable universe? Who knows?

[Beauj]

David, you need to ask Stephen Hawkins those questions!! But I don't think that it is possible to locate the centre of the sphere.

[wildwood]

Someone was on here some years ago and suggested (with tongue in cheek, no doubt) that the Milkyway and each galaxy is similar to an atom in a ginormous individual.

Try disproving it!

[rov1200]

What makes me think there has only been 1 big bang is that we are able to look back into space and see the beginning. If there had been further big bangs the view would have been obliterated.

[jake-the-peg]

Way to simple Rov.

You're also missing the point about the big bang being an explosion of space itself and not an explosion into a preexisting void.

Not surprising it's difficult.

Also because space and time are different faces of the same time when you roll the clock back to where there was no space there was also no time.

There was no before the big bang because there was no time