Received: by alpheratz.cpm.aca.mmu.ac.uk id AAA03550 (8.6.9/5.3[ref pg@gmsl.co.uk] for cpm.aca.mmu.ac.uk from fmb-majordomo@mmu.ac.uk); Thu, 31 Jan 2002 00:44:21 GMT Message-ID: <20020131003859.52438.qmail@web12308.mail.yahoo.com> Date: Thu, 31 Jan 2002 00:38:59 +0000 (GMT) From: John Croft <jdcroft@yahoo.com> Subject: Photons before the matter-energy decoupling 300,000 yrs To: memetics@mmu.ac.uk In-Reply-To: <200201280917.JAA03317@alpheratz.cpm.aca.mmu.ac.uk> Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: 8bit Sender: fmb-majordomo@mmu.ac.uk Precedence: bulk Reply-To: memetics@mmu.ac.uk
Dace wrote
> >> >It's common knowledge among physicists,
> >> >astronomers, cosmologists, etc., that light
> >> >didn't appear until 300,00 years after
> >> >the big bang (though I recently saw this figure
> >> >upped to 400,000, unfortunately without any
> >> >explanation for the revised figure).
Dace, this is incorrect. The 300,000-400,000 date was
that for te decoupling of matter and energy. Before
that decoupling energy was more important than matter
gravitationally. Scattering of light was such that
clumps of matter were "dampened" and prevented from
forming (a little like the dissipation of sound which
dissipates "compression and rarefaction" of matter
that propagates in a lineal fashion, before gravity
can take effect). In fact light was present from the
phase change of the electro-weak force into the
weak-interaction and electro-magnetism. This occurred
about 10^-12 seconds after the big bang, at about the
time of the Quark Hadron confinement phase change.
The Photon dominated Era began after 10^-10 seconds
when temperatures fell below about 1 MeV (Million
Electron Volts) as below that energy level
annihilation between pairs of electrons and positrons
exceeded pair creation. After that, the stage of
nucleosynthesis added still more photons to the mix
which finishes up with innumerably more photons per
baryon.
Hope this helps
Regards
John
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