On Sun 2006-01-08T11:44:04 -0700, M. Warner Losh hath writ: > How is it that UTC can be realized in realtime, but TAI isn't. I > thought the difference between the two was an integral number of > seconds, by definition. Is that understanding flawed?
I believe the claim would be that UTC(insert your national time service here) is realized in real time. UTC(USNO) is the official time of the US, and I suspect that there would be loss of face if any agency charged with keeping a national time did not, in some sense, proclaim autonomy. UTC(pick one) is, of course, directly related to TAI(pick one). TAI(anywhere) has no official status anywhere, except in the ex post facto statistical sense that it contributes to TAI (unmodified, the real thing from the BIPM). In an official sense of operational time scales, it is not clear that there really is anything such as UTC (plain old, unmodified) which differs from TAI by an integral number of seconds. As an identifiable entity, UTC (unmodified) may only exist within the text of ITU-R TF.460 -- 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
