[Keith Finelli]

Keith Finelli asked the Naked Scientists:
   
Love the show.  Just found it the other day and very interesting. 

Question:  If the further we look into space is like looking backwards into time and we can see the beginnings of the universe.  Then how did we end up so far away and much younger for the light at the beginning to just be reaching us now? 

Wouldn't this suggest the beginning of the universe wasn't at a single spot but rather billions of light years apart?  Does the big bang theory suggest that we started at this one point and within a single second reached the size that we see today, with respect to the fact that galaxies are continuously moving away from each other currently?

What do you think?

[Mr. Scientist]

I'll answer these - hold on

[Mr. Scientist]

''Question:  If the further we look into space is like looking backwards into time and we can see the beginnings of the universe.  Then how did we end up so far away and much younger for the light at the beginning to just be reaching us now?''

It has to do with 'not being far away spatially in relativity, but more of a journey made in time. Essentially we are no more far away from the big bang, than lets say hypothetically, Andromeda, or the cluster regions of distant space. Big bang actually happened everywhere, so every point on the spacetime map is geometrically-part of the big bangs origin.

Though, time being a universal invariant of space, means that the more we travel beyond local star systems, the more we find ''older resonents'' of the periods in which the universe was once volatile. The systems which we observe receeding at superluminal velocities in the observble horizon of the universe are in fact some of the youngest forms of matter which pervaded the universe around 10,000 million years ago - approximately-speaking.

But since theoretically-speaking, big bang happened everywhere, it would mean that space and time where not consistent to have one ''big bang'' alone. As Doctor Wolf once jokingly said with an air of theoretical truth, that ''we no longer think the universe as coming from a bang, but more of less gang-banged into existence.''

''Wouldn't this suggest the beginning of the universe wasn't at a single spot but rather billions of light years apart?''

Yeh, but not billions of years apart. More like 'every point on the spacetime map - each point perhaps seperated at a planck value of 10^-33.

''Does the big bang theory suggest that we started at this one point and within a single second reached the size that we see today, with respect to the fact that galaxies are continuously moving away from each other currently?''

Relatively-speaking, as soon as the big bang happened, there must have followed shortly after a big crunch. This is a timeless scanerio which has specific solutions for a Wheeler-de Witt analysis using diffeomorphisms to find a universe deviod of any time evolution. So in a sense, you cannot say - again just to clarify - big bang happened at a point - but might i add that the past-tense of the word ''happened'' is grammatically-false. Big bang is still happening. I posted this in the greatest myths of physics here in this forum.

The size we reached today however, is more or less down to your assumption; that is it a product of all points on the spacetime map to expand.