🚀 go-pugleaf

I am not a cosmologist, but since an e-mail message of mine was referred
to and possibly misunderstood:

 >  Hah, so there really was a "big flash" then.  Very interesting.
                                ^^^^^^^^^
Sorry, I don't see a "flash".  Before the recombination an observer would
have been immersed in a homogeneous, isotropic bath of black-body radiation
at around 6000 K, plus a bath of free electrons and protons of the same 
temperature.  Both had been cooling since the big bang; this was just the
point at which the temperature and density dropped enough to allow electrons
and protons to combine and make neutral atoms.

After the recombination, exactly the same radiation field was present, it just
didn't interact much with the matter any more, and the two components went their
own separate ways thermally.  But the ambient radiation field didn't get any
BRIGHTER.  No flash.

After recombination the radiation could cool only by expansion of the universe,
which preserves its black-body characteristics, just a change in temperature. 
That is, photons going away from you could keep going and never come back; but
photons coming toward you were increasingly red-shifted as your horizon expanded
with time. 

Ben