From: Hal Finney (hal@rain.org)
Date: Sun Jan 18 1998 - 09:26:35 MST
EvMick, <EvMick@aol.com>, writes:
> Skipping ahead a bit...Sheffield says...in regard to the Red Shift (the
> genesis for the idea of the big bang) ..."the most plausible mechanism, to a
> physicist, is the doppler effect'
>
> Oh? That implies there are OTHER mechanisms? I wonder what they are?
Ironically, doppler shift is probably *not* the best way of thinking
of the cosmological redshifts. Rather, what happens is that photons
are emitted by the galaxies, then as they travel, spacetime expands
and the photons get "stretched". Their wavelength lengthens, which
is a redshift. Doppler shift is quite misleading when dealing with
cosmological distances.
Hal
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