On Jun 27, 10:51 pm, Paul Rubin <http://[EMAIL PROTECTED]> wrote: > According to <http://en.wikipedia.org/wiki/UTC>, UTC is derived from > TAI.
According to <http://en.wikipedia.org/wiki/TAI>, TAI is a proper time, but the very first section in the TAI discussion page cites a refereed paper by the person then in charge of TAI which asserts that is not true. As for the primacy of UTC vs. TAI, this is the classical chicken and egg problem. The bureaucratic reality is opposed to the physical reality. > it's always within 20 nsec. This seems like the kind of correction > that can be applied after the fact. It is the nature of horology that *all* clocks need corrections applied after the fact. The question is whether a given clock and its time distribution system is good enough for the given application. > The difficulty/impossibility of computing intervals on UTC because of leap > seconds suggests TAI is a superior timestamp format. TAI is a superior time scale for processes on the surface of the earth which only care about nanosecond precision, but it is not practically available nor legal nor applicable off the surface of the earth. TAI is itself corrected after the fact by the issue of TT(BIPMxx). -- http://mail.python.org/mailman/listinfo/python-list