In message: <[email protected]> Rob Seaman <[email protected]> writes: : However, nobody has been arguing for rubber seconds. (Except on : extremely long timescales exceeding the current age of civilization on : Earth.) Your assertion is a straw man: : : http://www.nizkor.org/features/fallacies/straw-man.html
Actually, it isn't. Your arguments are so full of logical fallacies that I don't even bother any more. I know that nobody is proposing rubber seconds today. You know I know that. I'm saying that the second used to be a measure of the change in the earth, since it was a subdivision of the day. By its very nature, it was rubber, since it was a subdivision of something that was rubber. It is called historical perspective, and is quite relevant to your assertions that there's something inherently 'mean solar time' about UTC. There isn't. It is an atomic scale that is presently kept in sync with mean solar time. And there were rubber seconds from 1961 until 1972. The clocks were ticking at slight offsets to the atomic time to keep the atomic time scale (UTC) in sync with the mean solar time. This, I was arguing, was an extension of the prior 'rubber seconds' which were a division of the day, which was by its very nature rubber in length for a very long time. : Meanwhile, the length of day has been malleable since before the : Cambrian Explosion, let alone over any modern human timescale. We are : saying nothing new here. Correct. : The real observation is the familiar one of dual timescales. Focus on : the SI second and we see the world through atomic eyeballs. Focus on : the primacy of the definition of the day in civil timekeeping, and : Earth orientation pops out. : : Both timescales are necessary. I think we disagree about what is primary in the civil time keeping. I don't think it has to be mean solar time, except in a very gross sense of the terms. I think it can vary quite a bit from mean local solar time, and it will still work. I believe that the tolerance of local time is on the order of 10000 times less strict than the current practice of inserting a leap second when UT1 and UTC differ by too much (typically by more than .5s). It can easily tolerate a large variance and people are still cool with it. 10000x translates to something just over an hour. Warner _______________________________________________ LEAPSECS mailing list [email protected] http://six.pairlist.net/mailman/listinfo/leapsecs
