I think the reason that space is black is because our eyes cannot detect certain range of light spectrum, if we can rewind time a little would we be able to witness white colored space? This is a hypothetical question I simply wants to double check if my assumption is sound, I'm concern the universe took a very long time to become transparent then probably the afterglow will have already becomes CMB.
$\begingroup$
$\endgroup$
1
-
$\begingroup$ Btw, posts on Olbers' paradox $\endgroup$– Qmechanic ♦Commented Sep 18, 2016 at 12:37
Add a comment
|
1 Answer
$\begingroup$
$\endgroup$
The answer is yes, but you would have go back to before the epoch of recombination.
The radiation temperature of the universe is proportional to $(1+z)$, where $z$ is the redshift. The epoch of recombination is at $z=1100$ and the temperatue was 3000K. The sky would look red for radiation at this temperature (and there were no stars or galaxies then of course; they formed some hundreds of millions of years later).
To make the universe appear white you would need a temperature and hence redshift at least 3 times higher and hence this is at times before the epoch of recombination, some tens of thousands of years after the big bang.
However, there is a major difference. Whereas now you can see objects "in the past", at this early epoch the universe was opaque to radiation, so it would be more like being in thick (and very hot!) fog.
