# How the 10,000 Year Clock Works

The Inner Workings of the 10,000 Year Clock

Imagine the year is 09456. You're climbing into a cave in the foothills of Great Basin National Park, Nev. (presuming Nevada is still Nevada), when you stumble upon the 10,000 Year Clock. Standing 60 feet (18.3 meters) tall, you survey this sculpture of technology and scratch your head. What is it?

The clock is certainly eye catching. The dial face dares you to look beyond your place on Earth. A quick scan below reveals the heart of the machine.

The guts of the 10,000 year clock is an intricate array of moving parts that work in concert to not only keep track of all the clock's time measures, but also its music library. Because of the unique algorithm that controls the chimes, the clock never plays the same tune when it chimes. Also because the clock is a binary mechanical system, it needs an efficient way to regulate the precise movement. This is where the Geneva mechanism comes into play.

Geneva drives are systems that take regular rotary motion and convert it to an irregular motion. To do this, the Geneva drive uses a notched disk connected to an output shaft rotated by a spinning wheel. A pin on the rotating wheel catches the groove and turns it its prescribed distance, measured in degrees. The two types of Geneva disks or wheels are internal and external. Internal wheels contain the drive pin inside where as external wheels resemble stars that have portions cut out to allow the rotating cam to turn freely until the pin completes its 360 degrees of rotation.

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The chimes use a series of Geneva wheels and cam rollers that are controlled by the binary adder mechanisms. These binary adders make their calculations which are then converted through the complex cam-and-pin system.

While the mechanism looks complex, the science behind it is rather simple. Because the clock is mechanical and doesn't rely on electronics or other external sources of power, the hope is, those who seek it out in the future will see it functioning as intended.

The prototype clock, funded by the Long Now Foundation which raises money through donations and seminars, resides in the Science Museum of London. It began ticking on Dec. 31, 1999, just before the turn of the millennium [source: Lemley]. And while the world didn't stop running at midnight, Jan. 1, 2000, it did get its first peek at the 10,000 Year Clock. So what happens in another 10,000 years? On the next page, we'll take a look.