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Originally Posted by Redshift
This confuses me somewhat. It seems logical to me that 630 mil years after the big bang the universe would have been much smaller than it is today. So the light from that exploding star would have reached the earth (actually the earth wasn't around then, so by that I mean our point of reference in the young universe) in no more than 630 million years.
I would have thought that every point in the universe would have been much closer at that time and it has taken 13.whatever billion years to expand to the size it is now in a gradual way. So if that is the case then there is no "looking back" in time because the light from the early universe has already passed us by long long ago.
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I'm not much of an expert in cosmology, but perhaps this is the result of inflation. Shortly after the big bang, the universe expanded very rapidly, faster than light speed so light from close objects still took a long time to arrive as space itself was expanding. Secondly, off my head I've no idea about how big the universe was at 630 myo, but I think it would have been very large even at that tender age.
I reckon you will get better answers from those around that actually know what they're talking about.