[LEAPSECS] Looking-glass, through

Steve Allen sla at ucolick.org
Wed Jan 12 12:30:59 EST 2011


On Wed 2011-01-12T16:36:35 +0000, Tony Finch hath writ:

> Yes, but how accurately do you need clocks to track it? How frequently do

> you need to make adjustments to correct for the atomic/angular rate error,

> and what size of adjustment is acceptable?


It would appear that making adjustments every 10 days is not
often enough, at least in the US, viz:
http://www.nist.gov/pml/div688/grp50/NISTUTC.cfm
http://www.nist.gov/pml/div688/grp50/nistusno.cfm

Even if we abandon the leap second, we have issues at the nanosecond level.


> > For instance, what authority will historians or lawyers consult to learn

> > the applicable timezone offsets that were in force in some location(s)

> > during some epoch(s) in question?

>

> That problem exists whether universal time is atomic or angular so it

> makes no difference to the proposal.


When the leap second was invented there were countably few systems which
could count every second, so a second was not a problem. Now it is.

Right now there are countably few systems which can count every nanosecond.
Unless there is some sort of conceptual barrier which prevents a need
for nanoseconds, when such systems do become common the problem of
historic time zone offset reconciliation will be trivial by comparison
to the issues of systems which believe that nanosecond (picosecond)
synchronization is possible without table lookups and continuous
effort to track the table values.

Abandoning leap seconds simply sweeps the need for good timekeeping
practices under a rug rather than giving ongoing incentive to design
systems which match the way chronometers actually work.

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


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