[LEAPSECS] Schedule for success

M. Warner Losh imp at bsdimp.com
Wed Dec 31 01:00:02 EST 2008

In message: <495AFFEA.7020808 at cox.net>
Greg Hennessy <greg.hennessy at cox.net> writes:

: > It also agrees with the

: > USNO web pages, as well as the BIPM web pages. Would you like the

: > URLs?


: Since I don't consider them relavent, no thank you.

The problem is that GMT means several different things. It is an
ambiguous term.

Those web sites are relevant for at least one definition of GMT. GMT
is the mean solar time at the royal observatory, at least
historically. This means that there are no leap seconds. This is
approximately what is now called UT1. It differs from UTC, as it is
realized today, by a few hundred milliseconds either way (depending on
when the last leap second happened). For this definition see the

(note references to GMT being the mean SOLAR TIME (emp mine))
(in particular note that the legal time is based on GMT, not UTC,
implying they are different)
(which says it is equivalent to UT, which is a solar time)

More are a Google search away. At the very least, it shows that GMT
is an ambiguous term. At most it shows that it is a solar time,
different from UTC (although closely related).

This is one of the many reasons why UTC is the proper form.


More information about the LEAPSECS mailing list