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To: WSFAlist at keithlynch.net
Date: Fri, 9 Aug 2002 08:47:51 -0400
Subject: [WSFA] Re: constancy and the speed of light
From: ronkean at juno.com
Reply-To: WSFA members <WSFAlist at keithlynch.net>
On Thu, 8 Aug 2002 15:12:01 -0400 "Erica VD Ginter" <eginter at klgai.com>
writes:
> A piece on the speed of light--is it constant?
>
http://www.cnn.com/2002/WORLD/asiapcf/auspac/08/07/australia.lightspeed/i
nde
> x.html
>
It sounds like they are talking about the speed of light (in vacuum)
possibly having slowed over the billions of years of the cosmic
timescale. Such a long drawn out slowing, such a slow slowing if you
will, may be so slow in happening, if it really is happening, that the
speed of light may be taken as constant over short periods of time, but
changing over much longer periods of time.
Light waves which travel over billions of light years of distance, over
billions of years of time, get stretched out, or red-shifted, in the
expanding space of the expanding universe over that time. An additional
red shift is due to the rate of recession of the object which is the
light source. Perhaps a small discrepancy has been detected between the
measured redshift and the expected redshift, of very old very distant
objects, which discrepancy suggests the slowing of light. Paul Davies,
the team member mentioned in the article, has written a couple of dozen
books about cosmology and related subjects.
Ron Kean
.
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