[LEAPSECS] presentations from AAS Future of Time sessions

[Steve Allen]

On Thu 2014-01-16T01:33:53 -0800, Tom Van Baak hath writ:

> What is a typical example of the legal definition of a day?  Would

> that definition be affected if DUT1 were allowed to grow to 2 s or 10

> s or 60 s instead of 0.9 s?


In the United States one legal definition with significant financial
consequences is whether a child is born in one calendar year or
another, and the boundary is understood to be midnight.  It would be
interesting to know whether there is statute or case law saying
anything about how midnight shall be determined, but for the IRS
they are stuck relying on what the birth certificate says.

In practice the birth team has far more important things to do than
watch the clock.  I would not be surprised if in close cases the birth
certificates show more variation than the apparent solar day.  Taking
this toward reductio ad absurdum one could imagine fathers driving
prepartum mothers west across a time zone boundary.

That second question was basically one of the elements of Question
236/7 when the ITU-R got into this redefinition effort, and one of the
questions that the national delegates to the 2012 RA did not believe
was adequately answered by the draft TF.460.

I think the 2015 RA vote is also not going to depend on whether any
local jurisdictions have such a legal framework.  It's more likely to
depend on whether the national delegations believe that their
constituencies will tolerate a day being defined by cesium atoms
instead of earth rotation.

--
Steve Allen                 <sla at ucolick.org>                WGS-84 (GPS)
UCO/Lick Observatory--ISB   Natural Sciences II, Room 165    Lat  +36.99855
1156 High Street            Voice: +1 831 459 3046           Lng -122.06015
Santa Cruz, CA 95064        http://www.ucolick.org/~sla/     Hgt +250 m