[LEAPSECS] nails in the coffin of mean solar time

[Rob Seaman]

On Jun 15, 2007, at 12:19 PM, Poul-Henning Kamp wrote:


> In message <004001c7af81$2881ddb0$0300a8c0 at pc52>, "Tom Van Baak"  

> writes:

>

>> OK, fast forward through the last 40 years.

>

> One important thing to notice, is that notwithstanding the numeric

> ration of pieces of kit, the telescopes etc. are staffed by

> people with a significant clue in math and science, whereas at

> least half of the computer-encumbered stuff is "staffed" by people

> with below-average IQ.

>

> Common sense says to isolate the hard proplem to the few&smart

> rather than the many&dim...


Your argument does not fall on deaf ears (although see Gould's  
"Mismeasure of Man" regarding IQ).  And given your predilection for  
waving wads of cash in astronomers' faces, I'd be delighted to see  
your name on a review committee.  However, it simply remains the fact  
that there are two kinds of time - intervals and earth orientation.   
They will continue to generate competing requirements.  Astronomers  
themselves use both kinds of time.

The assertion that only astronomers (and sextant navigators) care  
about earth orientation is trivial to shoot down at the 1s per day  
(one leap hour per decade) level.  In fact, I think we wouldn't be  
having this discussion at the tenth second per day (leap hour per  
century) level.  The question reduces to whether anybody other than  
astronomers and navigators cares at the level of a few milliseconds  
per day accumulated drift.

An extensive inventory is necessary to answer that question.   
Rejecting its need beggars the imagination.  Having spent the time  
and money needed for such a "does this code need to introduce a DUT1  
correction?" inventory, we would still be faced with the prospect of  
what will actually happen to the embargoed leap seconds down the road.

Leap seconds are a conserved quantity, one way or another.

Rob Seaman
NOAO