Re: Cosmological redshift and Doppler shift

In article <[EMAIL PROTECTED]>,
Phillip Helbig---remove CLOTHES to reply <[EMAIL PROTECTED]> wrote:

>These are all limiting cases, so no problem.

Great!  That's all I've been trying to say.


>I hope we can ALL agree on the statement "if the redshift is large
>enough that the relativistic Doppler formula "should" be used, then the
>relativistic Doppler formula is completely inappropriate, in our
>universe".

Absolutely.

Moreover, I want to make it clear that I would only emphasize that the
low-redshift limit of the cosmological redshift can be viewed as a
Doppler shift when talking to a sufficiently sophisticated crowd.  In
particular, I wouldn't bring this fact up to anyone who didn't already
clearly understand that you *can't* do this at high redshift.

At some point, I'll try to write in detail about why I think it's
pedagogically useful to think about the cosmological redshift as a
Doppler shift in the low-redshift limit.  I don't think I have the
strength to embark on it now, though.

-Ted

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