In message <42F3647B.5060907_at_edavies.nildram.co.uk>, Ed Davies writes:
>Poul-Henning Kamp wrote:
>> ....
>> Also, your UTS proposal is a total non-starter: Rubber seconds is not
>> a usable solution.
>> ....
>
>Whether rubber seconds are usable or not depends on
>what problem you intend them to be a solution to.
Rubber seconds are _never_ usable, just like
rubber meters, rubber kilos and rubber unit charges
are never usable.
The entire point about the Meter Convention is to have
fundamental units so we can measure things and know
and agree what dimension they have.
>There is no single way of labelling time instants which
>is good for all applications.
Actually, that's the exact opposite of the truth:
We could label everything on TAI and be happy ever after.
In fact, that is the _only_ way we can be happy about timekeeping
*ever* after. Anything that involves the rotation of this lump of
rock runs into problems which we cannot possibly predict.
What happens when we get the next big earthquake ? I'm not talking
about the petty 8.0 or 9.0, I'm talking about the 12.0 that will
make Everest or Matterhorn even higher (Sure, it may be a million
years away, but I did say "ever after", didn't I ?)
Yes, some extra computation would be necessary when pointing a
telescope or showing off granddad's sekstant to the kids, but that
is just math which anyone who can use a sekstant or telescope can
learn to do. It will just make it feel even more quaint.
And yes, maybe it will be dark at 12:00Z some centuries from now,
but there is plenty of time to adapt to that as well. My
great-great-grandchildren will wonder why I had my clock with 12
facing upwards instead of downwards and so what ?
The *only* problem in switching to TAI that remains is that humans
are habitual and therefore any change is bad and everything was
much better in the good old days.
But people forget that a change to TAI would have a lot less impact
than the change to a common meridian or the change from local solar
time to timezones had.
Freezing the current UTC-TAI offset by abandonning leap-seconds
cuts 6 billion people out of the loop and that improves the chances
of progress a lot, which is why I support it.
And then centuries from now, students can say things like "what
morons, why didn't they get rid of those 33 seconds while they were
at it anyway ??"
--
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.
Received on Fri Aug 05 2005 - 06:46:09 PDT