On 12/23/2010 08:09, Rob Seaman wrote:
Which is to say that mean solar time is a requirement. Leap seconds as we currently know them are one possible way to implement that requirement. The latter is negotiable. The former is not.
Mean solar time is not a requirement. It is merely a tradition. As has been noted before, there has been a steady march away from mean solar time. Time originally was governed by the local solar time. Then, it was governed, for those in cities, by whatever the clock in the center of town said. Then timezones of the 1850's expanded the notion nations, and then internationally. We moved further away from the sun with the adoption of the second as based on the mean second of 1900, away from the second of the current era. Then we moved to atomic time kept in sync at first by its varying frequency. The most recent change has been to tick at a constant frequency but insert leap seconds into the labels we put on the seconds that tick by to keep things more or less in alignment to the earth.
Based on this history, it is far from clear that mean solar time is an absolute requirement. Mean solar time is another way of saying that time must measure the angle of rotation of the earth. Time keeping has moved beyond that one property. It is merely tradition at this point as many of the motivating factors for keeping UTC and UT1 in close harmony have changed.
While you make many good points, this point I think is the fundamental source of disagreement in this list...
Warner _______________________________________________ LEAPSECS mailing list [email protected] http://six.pairlist.net/mailman/listinfo/leapsecs
