We have not had to install or remove a leap second for a couple of years now, but normally we expect to on an annual or semiannual basis. The rotation rate of the Earth is, over all, slowing down but erratically when viewed over the past few billion years. This realization is part of what led to the use of atomic energy transitions as time standards.
Our ability to measure the rotation rate of the Earth and to measure time is now such that we can perceive and attribute the effects of weather on the Earth's rotation. That's perhaps a bit hard for some people to swallow but it's analogous to the realization during the Delambre/Mechain survey for the meter that the Earth was lumpy and that not all meridians are equal in length. That itself is what led to the use of a metal bar for the meter standard. Now, of course, we use the speed of light and our definition of time for that standard. Jim On Monday, 2004 February 16 08:17, Matthew Zotter wrote: > 2004 FEB 16 MON > > I support the second as it is already defined. There is no sense in > changing it; especially since the rotation of the earth changes with > respect to time. If I've heard right, we won't always have 24 h days. I > believe that we have to adjust our clock by 4 second a year right now. How > many days are there nowadays? Anomalistic, Bessel, calendar, Gaussian, > sidereal, solar mean, tropical, . . . Anyways, I think the > let's-change-time group is just one more obstacle to metrication in the > United States of America. I see a lot of good brain power being wasted on > this distraction. > > Sincerely, > Matthew Zotter .......... -- James R. Frysinger Lifetime Certified Advanced Metrication Specialist Senior Member, IEEE http://www.cofc.edu/~frysingj [EMAIL PROTECTED] [EMAIL PROTECTED] Office: Physics Lab Manager, Lecturer Dept. of Physics and Astronomy University/College of Charleston 66 George Street Charleston, SC 29424 843.953.7644 (phone) 843.953.4824 (FAX) Home: 10 Captiva Row Charleston, SC 29407 843.225.0805
