> On 2011-11-15 16:44, Warner Losh wrote: > > It is disheartening that the middle ground remains unexplored. Most > of the difficulty of the current system could be solved by > allowing DUT1 to grow as large as 10s, but still keep it bounded.
I work in broadcasting where we need accurate frequencies, and where the pictures are made up of an integer number of samples at those frequencies, and (here in the UK) we have exactly 25 whole pictures per second. Programmes are accurately timed, and if the clock time changes during transmission of a programme, then assuming the playout server doesn't crash, at the very least you will get one second of black, or a long freeze-frame at the end of the programme, as it will appear to finish sooner than expected. OK, not earth-shattering, and no-one will die as a result - it just looks untidy. But it is small enough to be swept under the carpet and ignored. Increase that step to 10 seconds, let alone a minute, and you would get a very noticeable and worrying pause, so I would not be in favour of that. However, let that step grow to an hour, and a) we won't have to worry about it for 25 generations (assuming an intelligent civilisation is present on Earth at that time), and b) we can treat it as we do a summer-time change at present, and just put the clocks back by a well-publicised hour. Now I'm not pretending that there won't be problems - clearly if you had two half-past-twos-in-the-afternoon on a stock exchange trading day, there could be confusion, so it would seem sensible to do it on a Sunday. Other scenarios will doubtless spring to the minds of readers, but we would have 600 years to consider and plan for it, meanwhile having a simple linear timescale. If our civilisation lasts for another 600 years without plague, asteroid impact, or atomic war wiping us out, then life will be very different to how we know it now, and future generations will doubtless have their own ideas about what they want from a civil time-scale. Given that Joe Public isn't even aware that solar noon varies by plus and minus fifteen minutes twice a year, let alone be affected by it, a very gradual drift will be totally imperceptible, so let's keep things simple for ourselves now, and let the future worry about itself. Part of the objections raised here seem to be to the continued use of the name "U.T.C." for this new leap-second free time-scale. I agree. It might be argued that it *is* still coordinated by virtue of "averaging" umpteen primary standards around the world. But I would expect a common understanding of the term would be to include leap-seconds, so let's use a new name: I believe TI - "International Time" has been suggested, but that can be discussed later. So there are legal ramifications - good grief, the lawyers get paid enough - let them sort it out amongst themselves. The concept is simple: "from day X, there will be no leap-seconds in civil time, and that timescale will be known as <insert name here>." How the lawyers turn that simple statement into legalese is surely trivial, and of no concern to those making the decision to change? Peter (London, England) _______________________________________________ LEAPSECS mailing list [email protected] http://six.pairlist.net/mailman/listinfo/leapsecs
