Dear db:

"db" wrote in message
...
"N:dlzc D:aol T:com (dlzc)" wrote:

Dear Ron:

"Ron" wrote in message
om...
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According to California Institute of Technology astronomer Jean-Paul
Kneib, who is the lead author reporting the discovery in a
forthcoming article in the Astrophysical Journal, the galaxy is most
likely the first detected close to a redshift of 7.0, meaning that it
is rushing away from Earth at an extremely high speed due to the
expansion of the universe. The distance is so great that the

I wish they wouldn't say it like this. Expansion is not a bunch of
individual objects "rushing away"... and a z (or even z+1) is not a
Doppler
shift. Maybe its just too easy to present it this way.

But "rushing away" does cause a Doppler shift, does it not?

Events that occur on the surface of the Sun are red-shifted. They are
red-shifted because the density of the space they occur in is higher than
where the events are measured... namely on Earth. So to say that those
events (on the Sun) are red-shifted because they are rushing away, is
incorrect. The ancient Universe had a much higher density. The red shift
we perceive of the ancient Universe as compared to the here&now is due
primarily to the density of the two Universes.

And yes, rushing away does provide a Doppler shift. And no, z+1 is not a
Doppler shift, not entirely anyway.

David A. Smith