The Clock of the Long Now

Via slashdot, a good write-up on Discover.com about the Clock of the Long Now and its just-completed second prototype. I love this project - it's one of the coolest things I've ever heard of.

What kind of machine can, for 10 millennia, accurately reconcile hours, days, weeks, months, leap years, leap centuries, the precession (wobbling around an axis) of planetary orbits, and, grandest cycle of all, the 25,784-year precession of the equinox?

Answer: a digital one. A calculation that extends to 28 bits is accurate to one in 3.65 million—or in clock terms, one day in 10,000 years. Bits and bytes are typically rendered electronically, but Hillis says he "rejected electronics from the start. It would not be technologically transparent and probably not durable. I could quickly see that the clock had to be mechanical."

For more information, details and philosophy, I recommend Stewart Brand's book, The Clock of the Long Now: Time and Responsibility: The Ideas Behind the World's Slowest Computer