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From: darrelj@sdcrdcf.UUCP (Darrel VanBuer)
Newsgroups: net.physics
Subject: Re: Atomic clocks - Who knows if they're correct?
Message-ID: <854@sdcrdcf.UUCP>
Date: Mon, 20-Feb-84 10:50:28 EST
Article-I.D.: sdcrdcf.854
Posted: Mon Feb 20 10:50:28 1984
Date-Received: Wed, 22-Feb-84 02:19:33 EST
References: <229@heurikon.UUCP> <163@ihopa.UUCP>
Reply-To: darrelj@sdcrdcf.UUCP (Darrel VanBuer)
Organization: System Development Corporation, Santa Monica
Lines: 20

Already, every few years, the timekeeppers find it necessary to insert a
leap-second every few years .  This is needed even if the atomic clocks were
set perfectly once because the earth's rotation is both wobbly and slowing,
the former causes a little jitter, the latter permanent effects.
Errors of a few seconds can be spotted with a good observatory (such as the
Naval Observatory at Anapolis and the one at Greenwich, England).
  Atomic clocks are already "more accurate" than the Earth's rotation and
revolution (in the sense of drift from an exactly constant second).
  By the way, in many millions of years hence, a day will be substantially
longer than 86,400 seconds, so "we" will have to decide how to restructure
timekeeping.  Do we inflate the second? the minute? use a 25 hour day? use
seconds since FOO and cumpute solar time?
-- 
Darrel J. Van Buer, PhD
System Development Corp.
2500 Colorado Ave
Santa Monica, CA 90406
(213)820-4111 x5449
...{allegra,burdvax,cbosgd,hplabs,ihnp4,sdccsu3,trw-unix}!sdcrdcf!darrelj
VANBUER@USC-ECL.ARPA