[time-nuts] The future of UTC

[cook michael]

Le 15/07/2011 07:57, Poul-Henning Kamp a écrit :
> <snip>
> Everybody but the time-lords have always been told to stay away from
> TAI in the strongest possible terms by said time-lords, who again and
> told the world to use UTC.
>

The time lords are not completely deaf. For more than 10 years there has 
been debate about whether or not to revert to a TAI scale, but consensus 
has never been obtained. There are three requirements for time 
transmission that the current system supports in recommendation ITU-R 
TF.460-6 which the americans are trying to vote out.

1. SI second ticks
2. corrections to UTC for earth rotation , DUT1, so that UT1 can be 
calculated.
3. A civil time scale, UTC which is a descendant of GMT and roughly 
measures the mean solar day. One or  other , if not both,  figure in all 
the legal codes of the planet.
   The definition of 3 ensures that there are  86400  +/-1 ticks per 
mean solar day .  This is quite useful as my watch and just about 
everyone else's measures days in 86400 units .

The proposed change to ITU-R TF.460-6 provides 1 but  removes 2 and 3. 
Sheer folly to my mind.

The current recommendation is good for another 2-300 years .

So in my humble opinion,  the proposition for change should be rejected 
until consensus be achieved and that ALL three above requirements are met.