How the 10,000 Year Clock Works

The 10,000 Year Clock prototype currently operates in the Science Museum of London. See more amazing timepiece pictures.
Photo by Rolfe Horn courtesy of The Long Now Foundation

As the new millennium approached, people around the world anticipated problems with computer systems crashing. Rather than writing software that used four-digit year codes, early computer programmers were limited to using two numbers to keep program file sizes small. However, many wondered if the world's computer infrastructure would crash due to the so-called Y2K problem. Left uncorrected, at midnight on Jan. 1, 2000, the practice would have caused many computers to believe the date was actually Jan. 1, 1900. As a result, the days preceding the turn of the century were tense as people waited to see what would happen. Organizations spent millions of dollars correcting the problem and Y2K came and went without serious problems.

If Y2K showed us anything, it exposed how short-sighted the human race can be sometimes. But not everyone was refusing to look ahead. As far back as the 1970s, a computer scientist named Danny Hillis had wondered what lay ahead after 1999. In 01996 (that's not a typo, as you'll see in a minute), he had a bold idea. Hillis, a methodical forward thinker, came up with the idea to create a clock that would transcend generations. His idea? Design a clock that keeps time for the next 10,000 years. For example, this article was published in the year 2009, but by Hillis's new clock, it would be the year 02009. But beyond adding another digit to our date, the clock would mean so much more.

The Clock of the Long Now, as it's officially dubbed, is meant to be an artifact capable of connecting our generation with generations to come. Nobody can predict with any accuracy what the world will look like in 10,000 years. Because there are so many variables, Hillis and his team had to take into consideration conditions in society the present human race doesn't deal with. This article explains the thought process behind designing and building a functional prototype and breaks down the inner workings of a clock that has to transcend time -- literally. We'll start by learning about the fundamentals of the Long Now Foundation and the reasons behind even considering such a clock in the next section. Take your time. As you'll find out, there's no need to hurry.

The Need for Long-term Thinking

The chimes on the 10,000 Year Clock, designed by Brian Eno, will never play the same combination of sounds twice over the course of 10,000 years.
The chimes on the 10,000 Year Clock, designed by Brian Eno, will never play the same combination of sounds twice over the course of 10,000 years.
Photo by Nicholas Chatfield-Taylor courtesy of The Long Now Foundation

The Long Now Foundation wants people to look at everything through the eyes of someone who may live 1,000 years. In other words, step away from the need to run, run, run without regard for your surroundings and take into consideration what your actions may do to the big picture.

Take Earth's climate, for example. Global warming is an issue that often sparks controversy on all sides. But while people try to devise quick solutions, the Long Now Foundation says it's important to consider the changes taking place now that will change the way the world works in the future. Long-term thinking gives way to short-term gain.

Hillis and his colleagues claim that if the human race can somehow collectively replace short-term thinking with a long-term approach, the world would ultimately be a better place now and in the future. But people are visual creatures. The need for a beacon -- a constant reminder -- often is the only way to get a point to stick.

Stonehenge is one such beacon. Speculation of its purpose ranges from an observatory to mark prehistoric events to a burial site. While little is known about the mysterious stone structure in southern England, it has stood as a lasting image of cultural thinking beyond anything seen recently. Hillis believes the Clock of the Long Now would be a present-day cultural reminder of generations past and a constant reminder of long-term thinking [source: Brand].

The clock symbolizes forward thinking, but it's also designed to function longer than any other clock in the world. On the next page, we'll begin to learn about its inner workings and the obstacles Hillis had to overcome before the prototype was built.

Building the 10,000 Year Clock Prototype

The tortional pendulum creates the timing for the 10,000 Year Clock.
The tortional pendulum creates the timing for the 10,000 Year Clock.
Photo by Rolfe Horn courtesy of The Long Now Foundation

When Hillis laid out all the parameters the clock needed to meet, several potential problems popped up. First and foremost was how to construct it so it would work for 10,000 years. Not only does it need to work for so long, it needs to be accurate. In addition, the clock needs to be universal enough to be able to be read in the future. Who's to say the human race will still use the same measure of time in the year 09234?

When posed with these questions, Hillis outlined some basic principles:

  • The clock should be able to work relatively free of regular maintenance and be accurate for the next 10,000 years.
  • The clock should be simple enough to maintain that if the world should fall back into a time without the technology that currently exists, maintenance wouldn't be an issue.
  • A close inspection of the operational principals should reveal the inner workings and principals behind its operation.
  • No matter what point in time someone comes upon the clock, it should be able to be improved upon.
  • The clock should be able to be constructed small enough to fit on a table if so desired. [source: Long Now Foundation]

When it came time to decide on a power source and the framework for keeping time, Hillis considered several options. Each had its drawback. For instance, using water and wind power would expose the mechanical structure to those elements. Tidal gravitational changes, seismic and plate tectonic movement and geothermal energy are all potential power sources, but because the clock needs to be able to be made small enough to fit in your living room -- scalability becomes a problem. Radioactive decay could work, but how would people feel about that? Electronics would power the clock, but what if electronics are just a fad?

Hillis's favorite method for powering the clock is for a person to wind the clock by hand, to encourage responsibility for the device [source: Long Now Foundation]. But for the prototype, two helical weights, similar to weight-gravity systems found in old clock towers throughout the eastern United States, are mounted on each side of the clock. The helical weights slide down drive tubes to create power. A torsional pendulum controls the timing and a solar synchronizer helps maintain accuracy. The pendulum doesn't tick away like a wristwatch. While a wristwatch ticks every second, the 10,000 Year Clock ticks once a minute [source: Long Now Foundation].

A serial binary adder converts the timing from the pendulum to one of six dials on the clock's face. The dials represent the year, century, sun (solar position), moon (lunar phase), horizons and star field. From the dials, you can decipher the hour, day, year, century and millennium. It was designed so anyone that stumbled upon the clock could read it. A manual is included as part of the design.

While that's a quick look at the construction of the prototype, the next section delves a little deeper into the inner workings of the 10,000 Year Clock. Continue reading to learn more about the mechanical binary mechanism as well as the Geneva drive system. You might be surprised to see how simple the logic behind the technology really is.

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.

Will the Clock Stand the Test of Time?

The Orrery uses the same type of mechanism as the 10,000 Year Clock to measure the movement of the planets.
The Orrery uses the same type of mechanism as the 10,000 Year Clock to measure the movement of the planets.
Photo by Nicholas Chatfield-Taylor courtesy of The Long Now Foundation

The prototype proved the clock's operation to be sound, but the permanent clock will be much larger in size -- 60 feet (18.3 meters) tall in fact, and will be able to withstand earthquakes and hold up to basic human interaction (but not vandalism). The ultimate location for the clock is to be inside a mountain with access only by foot. Two potential sites have been surveyed -- one in Texas on founder Jeff Bezos's property, and one in Mt. Washington in Nevada.

Even though the clock will be dependent on human input, the binary digital mechanism is accurate to within one day in 20,000 years [source: Long Now Foundation]. The clock is self-adjusting. On a sunny day, the clock prototype recalibrates at noon with the sun using a built-in solar synchronizer. At the precise time, a lens focuses a sunbeam to heat and expand a metal band inside the reset mechanism. Because the mechanism is so slow, ticking once per minute, the working parts do not wear out as quickly. In fact, the clock will tick as many times in 10,000 years as a mechanical wristwatch does in 100. While many wristwatches probably wouldn't last as long, the clock is built with endurance in mind.

Because of the clock's six-dial face, it's designed to be readable even if people use a different way of recording time. The moon, sun and stars are a universal constant. Unlike a clock as famous as the one in the English Houses of Parliament clock tower, which rings the famous bell known as Big Ben 24 times each day (once each hour), the 10,000 Year Clock will ring once a day. English composer Brian Eno designed the elaborate chimes to ring a unique tune each time. Over 10,000 years, the chimes would ring 3.5 million times, yet would never sound the same twice. The chimes themselves are a mechanical innovation. The brass chime tubes surround a series of phased Geneva wheels which are turned in tune with a progressive algorithm that generates a unique bell-ringing order each day. The larger version of the permanent clock will feature brass bells [source: Long Now Foundation].

The clock may prove to be nothing more than a conversation piece. But even if that's the case, it has served its purpose. For more information on clocks and related articles at, take a look at the links in the next section.

Related HowStuffWorks Articles

More Great Links


  • Brand, Stewart. "About Long Now." The Long Now Foundation. (Dec. 3, 2009)
  • Brittania History. "Stonehenge." (Nov. 21, 2009)
  • Chabon, Michael. "The Omega Glory." The Long Now Foundation. January 2006. (Nov. 21, 2009)
  • Encyclopedia Britannica. "Geneva Mechanism." (Nov. 22, 2009)
  • Lemley, Brad. "Time Machine." Discover Magazine. Nov. 26, 2005. (Nov. 22, 2009)
  • Long Now Foundation. "Orrery: The 10,000 Year Clock." (Nov. 17, 2009)
  • Long Now Foundation. The 10,000 Year Clock: Prototype 1." (Dec. 4, 2009)
  • Long Now Foundation. "The 10,000 Year Clock: Chimes." (Dec. 3, 2009)
  • Long Now Foundation: "The 10,000 Year Clock: Principles." (Dec. 3, 2009)
  • NASA. "2012: Beginning of the End or Why the World Won't End?" Nov. 6, 2009. (Nov. 21, 2009)
  • Rockets, Rusty. Science a GoGo. "Can the 10,000 Year Clock Save Humanity?" Sept. 2, 2005. (Nov. 19, 2009)