[alt.sources.d] WWS vs. The Naval Observatory Clock

istvan@hhb.UUCP (Istvan Mohos) (12/29/90)

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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heiby@mcdchg.chg.mcd.mot.com (Ron Heiby) (01/04/91)

I didn't watch any of the "live" New Year's shows on TV.  Somehow, I
can't picture the countdown:

10 - 9 - 8 - 7 - 6 - 5 - 4 - 3 - 2 - 1 - extra - Happy New Year!

:-)
-- 
Ron Heiby, heiby@chg.mcd.mot.com	Moderator: comp.newprod
"Give me voice mail or give me drugs!"/"Mandatory Drug Testing? Just Say NO!!!"

nigel@modcomp.uucp (Nigel Gamble) (01/04/91)

In <53611@mcdchg.chg.mcd.mot.com> heiby@mcdchg.chg.mcd.mot.com (Ron Heiby) writes:
>I didn't watch any of the "live" New Year's shows on TV.  Somehow, I
>can't picture the countdown:

>10 - 9 - 8 - 7 - 6 - 5 - 4 - 3 - 2 - 1 - extra - Happy New Year!

This is just as well, since the leap second had *already* happened
when the U.S. New Year's shows were being broadcast.  The leap second
occured at 00:00 UTC, which was 19:00 EST.

Now, if you were watching the celebrations in Trafalgar Square, London, UK,
you would have noticed a longer pause than usual between the Westminster
chimes and the first stroke of midnight of Big Ben.
--
Nigel Gamble					uunet!modcomp!nigel
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young (Gary Young) (01/05/91)

In article <53611@mcdchg.chg.mcd.mot.com> heiby@mcdchg.chg.mcd.mot.com (Ron Heiby) writes:
>I didn't watch any of the "live" New Year's shows on TV.  Somehow, I
>can't picture the countdown:
>
>10 - 9 - 8 - 7 - 6 - 5 - 4 - 3 - 2 - 1 - extra - Happy New Year!
>Ron Heiby, heiby@chg.mcd.mot.com	Moderator: comp.newprod
>"Give me voice mail or give me drugs!"/"Mandatory Drug Testing? Just Say NO!!!"

The second was added at Midnight UTC, Universal Coordinated Time.
So none of the North America "Happy New Years" coincided with the
extra second.

-- 
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        | Gary H. Young    young@mdi.com   Mobile Data International |
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dold@mitisft.Convergent.COM (Clarence Dold) (01/07/91)

in article <1991Jan4.205944.23322@mdivax1.uucp>,  says:

> The second was added at Midnight UTC, Universal Coordinated Time.
> So none of the North America "Happy New Years" coincided with the
> extra second.

So what happens to the tm struct verses seconds since epoch?
If my vague recollection serves correctly, we've added 5-6 seconds.
mktime() programs should be off by about 5-6 seconds from the date/time
that is correct, as the calculation would slip the leap-seconds.  
-- 
---
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