The question has both a frequency and a counter part, as does any clock. The frequency shift with gravity has been nicely addressed by tvb and others.
The counter of the frequency is subject to phase shift caused by the speed of light and the distance to the measured source. Each counter must be given an initial value of time in order to be called a clock. There can be no correction done at the source of the frequency. The user must make a distance/speed of light correction for his (rarely her) location. Try this old analogy. There is one clock in the center of town. It's pendulum is the only source of frequency. If you can't see the clock, then the bell is your only source of time. Different citizens at different distances will not hear the bell at the same time because of the speed of sound. If some of the citizens had astoundingly precise wristwatches, really fast reaction times, and different large distances from the bell, they would be surprised when they met at the monthly Gentleman's Time Club gathering to see that their watches did not match. Eventually Isaac Galilei would discover the speed of sound and deduce the reason for the offsets. Then the gentlemen would periodically meet under the clock tower to set their watches, and reckon the distances to their homes by the time offset. Bill Hawkins, who recently read Neal Stephenson's "Quicksilver." _______________________________________________ time-nuts mailing list -- time-nuts@febo.com To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.