On Jan 9, 2012, at 11:02 PM, Rob Seaman wrote: > Warner Losh wrote: >> It is only one possible definition, not the only one. That makes it a >> belief, not a mathematical identity. > > Alternate definition?
A SI second is defined by BIPM. Everybody knows that minutes have 60 seconds, hours have 60 minutes and days have 24 hours. Make that with SI seconds and you have the basis of the definition of a day: 86400 SI seconds. This is the "elapsed time" definition of a day, not an astronomical definition. It is an approximation of the astronomical definition, much in the same way that an SI second is an approximation of a second based on earth orientation. Pick an epoch in the 1950's and call it TAI and we have something with a 60 year track record, which is more than you can say for the current UTC :) Too bad the ITU thing doesn't include the 36 second delta for safety... Warner _______________________________________________ LEAPSECS mailing list [email protected] http://six.pairlist.net/mailman/listinfo/leapsecs
