[LEAPSECS] honest-to-god copper

Steve Allen sla at ucolick.org
Mon Jun 7 13:34:42 EDT 2010

In the Manhattan project plutonium was copper, and copper was
honest-to-god copper.

In the Java JSR-310 "Date and Time API"
we see this:

Time scales

The Instant class operates on a time-line model that doesn't
exist in reality. Specifically it assumes that leap-seconds
do not exist, and that there are always 60 seconds in a

These simplifications are useful because most applications do
not take into account the existence of leap seconds. If your
application needs to takeinto account leap seconds then an
alternate class is needed. The TimeScaleInstant class
represents an instant in time measured againsta specific
TimeScale. The supplied scales include TAI and True-UTC.

"True-UTC", as opposed to just plain "UTC". Just plain "UTC" is not
the entity defined by ITU-R TF.460, but a (dare I use the word)
proliferated time scale, something new created by them.

How long will it be before it is necessary to make the distinction
between "TAI" in JSR-310 and "True-TAI" as defined by BIPM?

I think I would call this not "proliferation" but "dilution of trademark".

Who is in charge of these time scales?
The defining agencies and their documents, or various different sets
of time scale users and their documents?

Steve Allen <sla at ucolick.org> WGS-84 (GPS)
UCO/Lick Observatory Natural Sciences II, Room 165 Lat +36.99855
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Santa Cruz, CA 95064 http://www.ucolick.org/~sla/ Hgt +250 m

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