Shape and Size of the Universe

[trossachs]

I've recently been thinking about the size and shape of the Universe and the thought process has developed a model of the Universe - well, in my mind anyway. I'm not an astronomer or astro-physicist so please forgive my naive assumptions. They're only based on a few things I've heard or read about the Universe, but here goes.

My first thought was, 'If the Universe started with the Big Bang, why do we see stars all around us?'

I've read some stuff about 'inflation' but my thoughts are more in line with the traditional Big Bang theory. This would mean that matter would fly apart from the centre and from some of the stuff I've read on this site, the Universe expanded at or near the speed of light. If you were moving away from a stationary object at the speed of light, then the light from that object would never reach you which means you would never see it. So if two objects were moving away from each other, both at half the speed of light, then you still wouldn't be able to see each other. If this holds true, why do we see stars all around us?

This led me to model the Universe as donut-shaped with the centre at the point of origin of the Big Bang. If you now imagine a line running around the centre, inside the donut, then the Earth is somewhere just off this centre line. This would mean that we now see stars all around us. I believe that our observable Universe is confined to a small part of the donut-ring and the limit of our observation is the outside of this donut; not across the void in the centre. I think this is why we can only see about 5% of the matter of the Universe - it would be interesting if someone did the maths and assumed that our current observable Universe is a spherical part of a donut ring.

The assumption that Earth is off-centre in the donut ring would also be supported by the recent discovery that the Universe is denser on one side of the sky, than the other.

Well; there it is. Comments anyone?

 

[Saiph]

Well, I'm going to knock a big hole in your underlying framework:

The stars aren't receding at faster than C speeds...so most of this isn't an issue. It's only the most distant galaxies (10+ billion ly) that are approaching (or are exceeding) this due to universal expansion. The local area most certainly is not. And stars are definitely considered 'local' as the visible ones are within only a few thousand ly.

As for a donut shape explaining why we only see 5% of the matter...doesn't work. We can only account some of the matter in areas that we can observe. This we extrapolate out to cover the entire universe.

 

[trossachs]

I would agree and expect that the 'local' stars are not receding at faster than C speeds, relative to the Earth, because they were sent on a trajectory similar to ours. If a star and its neighbour were pushed out from the Big Bang in a similar trajectory at near light speed, they would still be able to see each other. But those in opposing trajectories would never be able to see each other.