San Francisco, California

Long Now Orrery

A modern mechanical planetary system, part of a 10,000 year clock.

Inside the offices of the Long Now Foundation in San Francisco is a small museum dedicated to the art of long-term thinking. Surrounded by diagrams, molds, and assorted mechanical contraptions is the centerpiece: the orrery.

Designed as part of the ambitious 10,000 year Clock of the Long Now project (a model of which is at the Science Museum in London), the orrery is a modern incarnation of a the planetary models that rose to popularity during the Renaissance and Enlightenment.

This orrery was designed by Danny Hills and Alexander Rose of the Long Now Foundation, and installed in 2005. Made of a shiny silver colored nickel-copper alloy called monel, the eight foot tall machine shows the positions of the planets Mercury through Saturn, which are all of the planets visible to the human eye on Earth. It is designed to move twice a day, accurately sending the Earth round the sun, an orb made of yellow Mexican calcite, every 365 days, while Saturn will take 29.7 years.

Also on display in the museum are an early prototype of the chime system for the clock, and dozens of smaller models, prototypes, and a selection of books on related subjects.