On Sat 2008-09-13T13:26:07 +0100, Zefram hath writ: > After a mere four millennia at the current > rate of drift, TT(TAI) will not be accurate to the precision implied by > its defining equation: once the accumulated drift has exceeded 500 us, > TT will be better approximated by TT ~ TAI + 32.185 s. It's only a > matter of time before noon TT coincides with midnight TT(TAI)!
I noted when preparing my Delta T plots that the 1.e-12 change in the rate of TAI on 1977-01-01 amounts to a difference of 0.1 s at the earliest point on my plots, or less than 0.25 s at the earliest written records of humans. I can't imagine any astronomical observation which, even if described in totally unambiguous language, could make the distinction. I expect that at the time the astronomers who were unconcerned with the rate change of TAI had a similar viewpoint. Looking the other way, I still take a lesson from the agencies which launch payloads intended for rendevous. Their countdowns have always accepted the notion of a discontinuous "hold" in the time scale leading to a future event. -- Steve Allen <[EMAIL PROTECTED]> WGS-84 (GPS) UCO/Lick Observatory Natural Sciences II, Room 165 Lat +36.99858 University of California Voice: +1 831 459 3046 Lng -122.06014 Santa Cruz, CA 95064 http://www.ucolick.org/~sla/ Hgt +250 m _______________________________________________ LEAPSECS mailing list LEAPSECS@leapsecond.com http://six.pairlist.net/mailman/listinfo/leapsecs
