Leap second considered harmful

[David Farber <dave () farber net>]

Begin forwarded message:

From: Bob Frankston <Bob19-0501 () bobf frankston com>
Date: January 3, 2006 3:49:56 PM EST
To: "'Jonathan Thornburg'" <jthorn () aei mpg de>, "'David Farber'"  
<dave () farber net>
Cc: ip () v2 listbox com, "'Bob Frankston'"  
<Bob2-19-0501 () bobf frankston com>
Subject: Leap second considered harmful

Thanks for the pointer. http://www.cl.cam.ac.uk/~mgk25/time/ 
metrologia-leapsecond.pdf.

This is useful because it strongly affirms my claim that the leap  
second is a bad solution to a non-problem.

 “The primary reason for introducing the concept of the leap second  
was to meet the requirement of celestial navigation to keep the  
difference between solar time and atomic time small. However, the  
motivation for the leap second has diminished because of the wide  
availability of satellite navigation systems, such as GPS, while the  
operational complexities of maintaining precise timekeeping systems  
have made the insertion of leap second adjustments increasingly  
difficult and costly.”

In option #7 they note “It is thus unlikely that the growing  
difference between clock time and levels of daylight would be  
noticeable for the foreseeable future.”
Perhaps they are trying to fill up 21 pages in order to get published  
but it is quite clear that they are saying that the leap second only  
exists because of modern precision – the very same tools that give us  
the precision also give us the means for dealing with it as a  
correction factor.

Too bad they can’t come right out and say “get rid of it” but they  
come quite close.

I’ll admit that I’m bad at this kind of stuff because if the high  
order bit is wrong I don’t spend time on the low order bits. IN this  
case the high order bit is to introduce perverseness in basic  
computation rather than keeping it confined to a correction factor. I  
can only wonder why we ever allowed the leap second to happen in the  
first place.

It would be nice to get back on track and declare SUT (Simple  
Universal Time) based on time as if the leap second were never  
introduced and let the use of UTC be deprecated. That would add  
another set of calls to the time libraries but the code would be the  
same as the current UTC code since we’ve vary rarely implemented real  
UTC but it would accommodate programs that actually did.



-----Original Message-----
From: Jonathan Thornburg [mailto:jthorn () aei mpg de]
Sent: Tuesday, January 03, 2006 10:37
To: David Farber
Cc: ip () v2 listbox com; Jonathan Thornburg; Bob Frankston
Subject: Re: [IP] more on Leap second fight brewing



Bob Frankston wrote:

> I still don't understand the purpose of leap seconds on the human  
scale. I

> understand correction factors but I don't understand this  
fundamentalist

> view of time.



There's (what I think is) a nice summary of the issues at

   http://www.iop.org/EJ/article/0026-1394/38/6/6/me1606.pdf

which can also be found (free!) at

   http://www.cl.cam.ac.uk/~mgk25/time/metrologia-leapsecond.pdf



ciao,



--

-- Jonathan Thornburg <jthorn () aei mpg de>

    Max-Planck-Institut fuer Gravitationsphysik (Albert-Einstein- 
Institut),

    Golm, Germany, "Old Europe"     http://www.aei.mpg.de/~jthorn/ 
home.html

    "Washing one's hands of the conflict between the powerful and the

     powerless means to side with the powerful, not to be neutral."

                                       -- quote by Freire / poster  
by Oxfam



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