[ntp:questions] Leap second question

unruh unruh at invalid.ca
Thu Mar 21 00:29:03 UTC 2013


On 2013-03-20, Harlan Stenn <stenn at ntp.org> wrote:
> To date there has never been a deleted leap second and one is not
> expected.
>
> It is arguable that we should code for this possibility in case one
> happens, and on the flip side of that we're introducing the potential
> for something else to break.

There was a long period just before the recent couple of leapseconds
wehre there were none (5 years?) Ie, that steady progression of the
earth slowing was interruped, not because tidal braking stopped but that
other offects (plumes within the earth-- eg a big lump of cold rock sank
toward the center of the earth) compensated. They could have
overcompensated just as well. The leap standard calls for the
introduction of leap seconds of either sign and surely ntpd should allow
for that. 

>
> While some earthquakes could effectively "decrease" the diameter of the
> planet (and speed rotation a bit), a good number (most?) of them go the
> other way, slowing the rotation a bit.
>
> H



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