Response from Richard Heck on October 9, 2005

[[Now that someone with actual knowledge has answered this question, I'm removing my speculations.]]

Response from Alexander George on October 9, 2005

The following comment has been kindly sent in by Professor Kannan Jagannathan (Department of Physics, Amherst College):

"The best evidence we have for the isotropy and homogeneity of space leads cosmologists to hold that the universe has no center and no periphery. If the universe is infinite now, it was so at the Big Bang, and the bang occurred everywhere (in such a case, the density of the universe would have been infinite at BB); if the universe is finite (and unbounded) now, it was probably point-like at BB, but it is not to be thought of as embedded in some larger space. That was all there was as far as space was concerned; it was 'everywhere' then, and is everywhere now.

In the standard model of cosmology, as well as in most variants of it, the initial rate of increase of the scale parameter (crudely, the radius of the universe, or the rate of expansion of space) would have been bigger, perhaps much bigger, than the speed of light. The combination of these two points would suggest that if light was emitted at BB, we would still be receiving bits of that light from parts of the universe that had sped away too fast, and we would continue to do so for the foreseeable future, particularly if any of the inflationary scenarios is taken seriously.

The reason the earliest light is from something like 300,000 years after the BB is because that is when the universe had cooled enough to allow neutral atoms to form, and the universe suddenly became transparent to electromagnetic radiation. Prior to this so-called 'recombination era' (a misnomer since it was the first time that the 'combination' could have occurred), the universe was opaque to all 'signal carriers' that we can think of or detect easily; if one goes a little farther back in time than 300,000 years, even the neutrinos would have scattered too much to be available as a faithful imprint of events before."