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Re: [Phys-l] leap second limbo

One 'serious' (I say ludicrous) proposal to avoid the leap second 'problem' is to allow the corrections to accumulate until they equal a full hour and only THEN incorporate the hour of correction.

Since this would take several centuries to happen - it essentially 'kicks the can down the road' making it somebody else's 'problem'.

Did any disruption occur when the last leap second was added in 2008?
Not the _*I*_ noticed.

Even MicroSoft could figure this out how to handle it if they cared enough to.

The GPS system won't be disrupted (as many have claimed) since it is independent of UTC.
At 9:07 PM -0500 1/19/12, chuck britton wrote:
I find the WikiPedia article on Leap Seconds
( to be a bit more complete
than the Aljezeera article. Folks will tell me where the wikipedia
article falls short I am

There are already two well established 'geek' time definitions that
do not have leap seconds. These are International Atomic Time (TAI)
and Global Positioning System (GPS) time.

UTC is purposely 'adjusted' to synch with the earths rotation.

For those who don't want to be bothered by such synching - they can
rely on TAI or GPS time keeping. I see this 'problem' as one that is
exactly the same as leap years. Just on a finer scale as time keeping
has advanced in precision.

The proposal to stop adding leap second corrections will NOT be
decided until 2017 at the earliest. Technology should be able get
it's act together by then.

At 2:26 PM -0700 1/19/12, John Denker wrote:
> Timekeepers at a meeting in Geneva have failed to agree on a proposal
to abolish the 40-year-old practice of adding the occasional second
to atomic time, in order to bring it in alignment with world time as
told by the rotation of the Earth.

The International Telecommunication Union put off the decision at
Thursday's meeting, saying more study was needed into whether to
scrap the leap second.

Let me ask the obvious dumb question: Given that there are conflicting
objectives, why not just have *two* time systems:
-- civil time (locked to the earth's rotation, with leap seconds)
-- nerd time (no leap seconds)

In particular, consider the analogy to time zones and daylight savings
time. All well-behaved computer operating systems keep time in UTC
internally, and use an elaborate ephemeris to convert to the local time
zone, if/when needed.
(The exception is Microsoft Windows, which *still* tries to keep
the hardware clock in local time, believe it or not. You might
think this would be a disaster for anybody who travels across time
zones, and you would be right.)

So, why not let computers and GPS satellites etc. keep nerd time, and
then publish an ephemeris that documents how to convert nerd time to
civil time if/when needed?

The two time systems *will* drift. Wishing will not make the drift go


Switching now to spacelike directions, people have been dealing with an
analogous issue for many years: Due to continental drift and whatnot,
the lat/lon coordinates of geologic features *must* drift over time.
You can choose a datum to minimize the drift of things you thing "should"
be considered fixed points, but you can't get rid of all drift. As a
result, when plotting stuff in North America, you have to decide whether
to use the North America Datum (NAD 83) or the World Geodetic System
(WGS 84). They differ by a meter or so.

Also note that both of them differ by about 100 meters from the classical
prime meridian as defined by the Royal Greenwich Observatory.

If the geodesy guys can handle drift, why can't the timekeeping guys do
the same?
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