Re: [LEAPSECS] TAI-UT1 prediction

From: Markus Kuhn <Markus.Kuhn_at_CL.CAM.AC.UK>
Date: Thu, 20 Jan 2005 18:29:43 +0000

Tom Van Baak wrote on 2005-01-20 17:33 UTC:
> No one can know for sure but I was wondering if
> there is a consensus on when the first leap hour
> would occur?

A good table summary of some projections is in

and other discussions are on

and there in particular in

  Prediction of Universal Time and LOD Variation - D. Gambis and C. Bizouard, (IERS)

> Even to an order of magnitude? I
> ask because the above document draft says "at
> least 500 years" while others here cite numbers
> like 600 years, or 5000 years.

5000 years until the next leap second sounds like someone got some very
basic maths wrong (by then, a whole leap day would be due), the other
two figures sound feasible. Perhaps a confusion about the rotation of
earth (UT1 clock frequency) slowing down roughly linearly, therefore the
accumulation of the phase difference being (after integrating) an
essentially quadratic function?


Markus Kuhn, Computer Lab, Univ of Cambridge, GB | __oo_O..O_oo__
Received on Thu Jan 20 2005 - 10:30:07 PST

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