--- Danny Hillis <danny@appliedminds.com> wrote:
I am building a mechanical clock that is intended to show the position of the visible planets and the phase of the moon over the next ten thousand years.
You will need to take into account the secular slowing of the Earth's rotation due to tidal friction. According to the 2005 Observer's Handbook, this effect lengthens the day by 1 second about every 40,000 years. Over 10,000 years, the average day will be 1/8 s longer, so the accumulated error (if the slowing is neglected) is (1/8 s/day) x (360 day/year) x (10,000 year) = 450,000 s, or 5 complete rotations. Gene __________________________________ Do you Yahoo!? Yahoo! Mail - Easier than ever with enhanced search. Learn more. http://info.mail.yahoo.com/mail_250