[LEAPSECS] Cost: getting rid of GMT & discontinuing leap seconds

ashtongj ashtongj at comcast.net
Sun Oct 24 12:08:03 EDT 2010

Here is a cost that has not yet been mentioned. Many sources still refer
to the basis of civil time (before adjustment for time zone and daylight
saving) as Greenwich Mean Time. This can still be justified because
although the meridian for which UTC is the mean solar time moves over
the surface of the earth, and does not consistently pass through the
crosshairs of the Airy transit, it most likely remains on the Royal
Observatory, Greenwich. (I estimate 0.9 s of time corresponds to about
260 m at that latitude.) Even if the meridian does not stay on the
grounds, it at least stays within the London Borough of Greenwich. But
once leap seconds are abandoned and |UT1 - UTC| becomes large enough to
move the meridian entirely outside Greenwich, it will be necessary to
modify all textbooks, monuments, and museum exhibits containing
explanations of civil time accordingly. It will also be necessary to
modify all computer programs which keep civil time to replace GMT with
the appropriate symbol (I have supposed the symbol UTC will continue,
but who knows).

Some may think that the preceding paragraph is light-hearted, and maybe
it is. I do think, however, that the time keeping authorities in
English-speaking countries have proven incapable of getting the public
to stop using the symbol GMT. Indeed, NIST and USNO have so little
influence on the rest of the government that they can't even get the US
government to stop using the symbol GMT. The inability to enforce
whatever decision is finally agreed to is a concern.

Gerry Ashton

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