📅 Monday, August 17, 2026
Designed by Danny Hillis and funded by Jeff Bezos, the Clock of the Long Now is engineered to tick once a year for ten millennia. Instead of conventional mainsprings, it is powered entirely by daily temperature variations, using a mechanical brass and steel linkage to synchronize itself with solar noon.
Hidden deep inside a remote mountain in West Texas, engineers are constructing one of the most extraordinary mechanical timekeepers ever conceived: the Clock of the Long Now, designed to keep time for an astonishing 10,000 years. Conceived by Danny Hillis as a monument to long-term thinking, the immense mechanism occupies a vertical shaft roughly 500 feet tall and is being built from durable materials including titanium, ceramics, quartz, sapphire and stainless steel.
Its power system is even more remarkable. The clock can harvest mechanical energy from the temperature difference between day and night, while visitors can also manually wind its enormous mechanism. Stored energy drives the timekeeping system, and Long Now says the solar system can provide enough winding force to keep its pendulum operating without human intervention for extremely long periods. So rather than saying it is powered entirely by temperature variations, I’d describe it as a clock capable of harvesting thermal energy while also accepting human winding.
But keeping a machine running isn’t enough—it also has to know whether it is still correct. The clock therefore uses the Sun as an astronomical reference. Sunlight enters the mountain and heats a chamber of air, moving a graphite cylinder and producing a mechanical signal used to synchronize the clock to solar noon. An ingenious mechanical Equation of Time Cam compensates for variations caused principally by Earth’s orbital eccentricity and axial tilt.
And this isn’t simply a gigantic clock face. Its mechanical displays are designed to show astronomical and calendrical information, while a mechanical chime generator created with input from musician Brian Eno can produce more than 3.5 million unique bell sequences—one for every day the clock is visited across 10,000 years. The goal isn’t merely to measure time; it’s to make people imagine a future extending thousands of years beyond their own lifetime.
💡 Did You Know?
The clock doesn’t need to spend precious stored energy constantly updating everything a visitor can see. It can internally keep track of the correct time while leaving its display unchanged. When someone eventually arrives and winds the display mechanism, the calendar wheels advance until they catch up with the time the clock has been keeping
Category: Fun Quirk
Disclaimer: Every effort has been made to keep these watch facts accurate, but the world of horology is full of myths, disputed stories, and fascinating trivia. Consider these facts a starting point for discovery rather than the final word. If you have corrections or additional insights, let us know—we’re always happy to keep the record ticking in the right direction.
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