time, standard (GMT) The local time on the Greenwich
meridian, based on the hypothetical mean sun (which averages
out the effects of the Earth's elliptical orbit and its tilted
axis). GMT is the basis of the civil time for the UK.
In 1925 the reference point was changed from noon to midnight
be used for the new GMT.
Authorities disagreed on whether GMT equates with
UT0 or
UT1, however the differences between the two are of the
order of thousandths of a second. GMT is no longer used for
scientific purposes.
(2001-08-02)