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Re: Cosmological redshift



Space and time both change in ways that conspire to keep c constant.
However, that has no effect on the value of the standards since they
are locally defined. You measure larger intervals because more of
your standards fit.

David Bowman wrote:
. . .
Recall the definition of the meter: (1/299792458) of the distance
that light travels in 1 second. The standard of length is tied to the
defined factor c. As the universe expands the value of c, being defined as
a particular constant, does not change. Since c stays the same throughout
the expansion process, the length of the meter (and thus the centimeter
above) also remains constant.
. . .

What about the duration of a second? Does it change?
Since c is distance per time, it is not obvious which changes
and which does not change (or do they both change) to keep c fixed.
Is it not space-time which expands, and not just space or time?
Please clarify.

David Bowman
dbowman@gtc.georgetown.ky.us

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