WWS vs. The Naval Observatory Clock

[Istvan Mohos]

>From a Dec. 1990 issue of the New Jersey "Star Ledger" daily
newspaper (USPS 519-520):

                1991 to be delayed by a 'leap second'
                -------------------------------------

WASHINGTON (AP) --- Wait just a second.

The start of next year will be delayed by circumstances beyond our
control.

The authorities in charge of time --- yes, there are such people ---
have declared that a "leap second" will occur at the end of 1990,
extending the year ever so slightly.

Why?  Because clocks have become just too darn accurate in recent years.

Today's atomic clocks are accurate to within a billionth of a second a
day, according to the U.S. Naval Observatory, the office in charge of
keeping track of what time it is.

The good old Earth, on the other hand, isn't nearly that consistent.

It speeds up a bit sometimes, slows down other times.  The Earth is
consistent to only about one-thousandth of a second a day, reports the
National Institute of Standards and Technology, the agency in charge
of measuring units of time.

It used to be that slight irregularities in the Earth's rotation didn't
matter.  But modern clocks get out of time with the slightly wobbly
world.  Because the planet can't be adjusted, the clocks must be.

Since the Earth has slowed a bit, the clocks have been gaining time and
must be slowed to keep them accurate.

This year's leap second will occur at 23:59:59 universal coordinated
time.  That's 6:59 p.m. and 59 seconds, EST.

Normally, 6:59:59 p.m. is followed by 7:00:00.  But on Dec. 31 it will
be followed by 6:59:60, and that will be followed by 7 p.m.

Universal coordinated time, formerly known as Greenwich Mean Time, is
the international time standard.  The extra second is added at 23:59:59
so it will occur just before midnight and the start of the new year.

This will be the 16th leap second.
-- 
        Istvan Mohos
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        1000 Wyckoff Ave. Mahwah NJ 07430 201-848-8000
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