On Mon, 14 Feb 2005 05:08:56 GMT, "David Nakamoto"
wrote:

One way is to take the measurements in a binary system. From the spectral type
of the component stars, an estimate of their distance, and their orbital period,
all measurable through telescopes and some inferring, you can get the pairs
motion around each other and through space, at least in the line of sight. From
this you can eliminate causes of red shift due to motion, eliminate them, and
uncover other red shift effects.

This was, in fact, how gravitationally induced red shift was measured for the
first time, using the white dwarf companion of Sirius, I believe, if not the one
around Procyon, but I believe it was Sirius. The period, mass, and the pair's
mutual motion through space are measurable or can be calculated from the
observed. From this, all red shifts due to motion can be eliminated. Then
because the companion has a high surface gravity, it can produce a gravitational
red shift, which was what was left when the other causes were eliminated, and it
matched what Einstein predicted for the mass of the companion.
Gravity can be ruled out pretty much because it is a feeble effect.
The sun has pretty good gravity 27G but the gravity redshift z = 635/c
= 0.0000021.
A galaxy with this shift would have Doppler velocity of 635km/second
which is very small cosmologically, well, 0.0000021 of c. The distance
computed using Hubble's constant would be 30,000 LY which is only
about 1 2 millionth of the radius of the universe (13BLY).
Mr. Dual Space

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