Hi One would assume that mean sea level / 1 G would be the standard reference point for the "official" Cs transition. I've never seen anybody pull out a gravity meter to set up their Cs though. I suspect that NIST has at least done the math.
Bob -----Original Message----- From: [email protected] [mailto:[email protected]] On Behalf Of Mike S Sent: Thursday, July 14, 2011 6:26 AM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Primary Time Standards At 10:26 PM 7/13/2011, Jim Palfreyman wrote... >But why is it that Caesium Clocks and Hydrogen Masers have an >adjustment >facility? Cs defines the second, but only at the physically impossible temperature of absolute zero. Relativistic effects make it so the second is a different length at different altitudes. So, when one wants to track global "mean" time, individual clocks need adjustment. Which brings up another question - what altitude (=geoid?) is TAI defined for? I don't know enough about general relativity, but think the latitude would make a difference, too? _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there. _______________________________________________ time-nuts mailing list -- [email protected] To unsubscribe, go to https://www.febo.com/cgi-bin/mailman/listinfo/time-nuts and follow the instructions there.
