Yes, and no.. Time as we know it (UTC) is coordinated at the BIPM in Paris between observations from primary standards at contributing laboratories and also earth rotation measurements. Each lab contributing will at any time (excuse the pun) have a small time offset with regard to UTC. E.g. time from NPL in UK would say be offset from UTC at any time by a few microseconds, and would be designated UTC-NPL. Worth reading http://www.npl.co.uk/science-technology/time-frequency/time/
Interestingly there is a lot of research into more stable clocks using Mercury and Ytterbium. This then leads to discussion about a future possible re-definition of the second (which IMHO will happen). Rob Kimberley -----Original Message----- From: time-nuts-boun...@febo.com [mailto:time-nuts-boun...@febo.com] On Behalf Of Mike S Sent: 24 February 2010 12:14 PM To: Discussion of precise time and frequency measurement Subject: Re: [time-nuts] Primary Standards... At 07:46 PM 2/23/2010, Rick Karlquist wrote... >The TAI is a weighted average to improve short term stability and >to average out random frequency errors. IOW, there is a variance from clock to clock. So, if there are 80 different clocks, are there 80 different seconds, or 80 imperfect clocks? Is this a problem with the definition (i.e. Cs resonance is unstable), or with the clocks? _______________________________________________ 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. _______________________________________________ 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.
