[time-nuts] UTC ~ GMT

Poul-Henning Kamp phk at phk.freebsd.dk
Mon Aug 1 02:33:26 EDT 2005


In message <9ED1AE2E-9E1D-4E6C-A16A-A47470E4454E at noao.edu>, Rob Seaman writes:

>Any serious  
>proposal should include a serious risk analysis.  Since we're talking  
>about changing an international standard that has held for 30+ years,  
>the onus falls on the group proposing a change.

And I think you will find that it was such a risk analysis which
provoked the USAs proposal.  Admittedly, it was probably only the
risk to some minor systems with no astronomical significance, so
astronomers will probably just dismiss or at least ignore it.

If you think for a moment what a risk study carried out by the DoD
will say about astronomers telescopes, then you'll probably see
the wisdom in astronomers doing their own risk analysis.  At the
very least, leaving that to the opposition is not going to be
a winning strategy.

>> That's probably true, but since DUT is only relevant if you study  
>> extraterrestial objects, we can safely assume that 99.9% or more of  
>> those systems involve astronomers and optics.
>
>The Sun is an extraterrestrial object.  We study the Sun not only due  
>to basic scientific curiosity, but because everything we do on the  
>Earth depends on the Sun.  Civil time is solar time because no other  
>periodic phenomenon so dominates our lives.  Leap seconds are the  
>mechanism that is currently used to synchronize our clocks to the  
>solar day.  Your assumption of safety is in reality a source of  
>extreme danger until proven otherwise.

For the Sun it has been proven emperically for more than a century
that no harm happens to civilization for up to 30 and in some cases
even 45 degree offset from the "astronomy approved" position, that
means that we're safe for at least half a millenium.

>In a world without leap seconds, one interpretation is that Greenwich  
>will start drifting monotonically out to sea.

You don't need to interpret GMT, the british parliament decides how
it is to be interpreted.

>Astronomers have been following - and leading - such discussions  
>since this issue reared its ugly head.  It is not our fault that the  
>policy makers don't choose to participate in the same forums.

You know, if the mountain doesn't come to Mohamed...

>I reject your premise that bureaucrats are now the "real timekeepers".

They may not be the real timekeepers, but they hold the purse strings
and have a heck of a lot more influence than the "real timekeepers",
which they can eliminated with a single line in a budget.

>Sometimes argument is the only activism available.  I believe  
>"unofficial" discussion is the only reason the "official" process has  
>not proceeded to its intended completion.

As far as I can tell, it is 100% on track and the unofficial
discussion hasn't had any effect at all on the timetable.

-- 
Poul-Henning Kamp       | UNIX since Zilog Zeus 3.20
phk at FreeBSD.ORG         | TCP/IP since RFC 956
FreeBSD committer       | BSD since 4.3-tahoe    
Never attribute to malice what can adequately be explained by incompetence.




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