10,000 Years Later…

A clock is ticking inside a mountain in Western Texas.  It is a monumental clock.  Hundreds of feet tall, its mechanism is designed to tick for 10,000 years.  It’s a real clock.  The first of several millennial clocks being built around the World, to endure for centuries.  Tick…  

10,000 years later…


Time is ticking.

The ticks of time are a very human invention.  The idea of building a 10,000 year clock originated in 1986, or if you will in 01986.

The Clock of The Long Now

Danny Hillis (centre back) and the Clock’s engineering team. Source: LongNow.org

Danny Hillis is the polymath inventor of this clock.  Together with a biologist (Stewart Brand) and a rock musician (Brian Eno), he launched a not-for-profit organisation to construct the Clock: The Long Now Foundation.

“I want to build a clock that ticks once a year.  The century hand advances once every 100 years, and the cuckoo comes out on the millennium.  I want the cuckoo to come out every millennium for the next 10,000 years.”

Danny Hillis,

Clock Designer

Designing the World’s Slowest Computer

The first milestone of this multi-decade project was to design a working 2.4-metre (8-foot) tall prototype of the Clock, which was fortuitously completed on New Year’s Eve 1999, on time to welcome the new Millennium.

The basic design principles for the Clock are the following:

    1. Longevity: The clock should be accurate even after 10,000 years, and must not contain valuable parts (such as gemstones, precious metals or alloys) that might be looted.
    2. Maintainability: Future generations should be able to keep the clock working, if necessary, with nothing more advanced than Bronze Age tools and materials.
    3. Transparency: The clock should be understandable without stopping or disassembling it; no functionality should be opaque.
    4. Evolvability: It should be possible to improve the clock over time.
    5. Scalability: To ensure that the final large clock will work properly, smaller prototypes must be built and tested.

The first 2-metre tall prototype of the Clock of the Long Now resides in the London Science Museum.  At midnight on New Year’s Eve, the date indicator changed from 01999 to 02000, and the chime rang twice.


Astronomical Feat of Engineering

The full scale Clock has been undergoing construction.

Building something designed to last 10,000 years requires much optimism and a great dose of knowledge.

This footage (above) from 02011 shows the completion of the 500 foot deep vertical shaft for the 10,000 Year Clock in West Texas.

The engineering challenges for the Clock are phenomenal.

  • What material do you build it with?
  • How do you maintain its accuracy?
  • How do you keep it powered?

The technical solutions are rather ingenious.

Stainless Steel and Ceramic Components

Almost any artefact can survive millennia, provided it is carefully preserved.  Museum shelves are filled with thousands year-old papyri, everyday wooden objects, even leather footwear.

The Clock is a machine.  It has moving parts.

And metallic clockwork components can corrode and wear down as lubricants evaporate, sometimes within just a few years of rain or weather exposure.

For this reason, most of The Long Now Clock is made of marine grade 316 stainless steel.

The engineering tolerances are unlikely to be affected by a microscopic film of rust at this monumental scale.  But where corrosion will not cause a problem, galvanic corrosion could well be an issue.

The elements of the Clock need to move so slowly as not to move appreciably at all during the course of a lifetime.  Over the required timescales, the prolonged contact of similar metals can fuse them together, and dissimilar metals can ‘eat’ each other.

To counteract these natural tendencies, the key moving elements of the Clock will be made of stone or hi-tech ceramics.

Ceramics can outlast most metals.  Archaeologists have in fact retrieved shards of clay pots 17,000 years old.  And modern ceramics can be as hard as diamonds.

All the bearings in the Clock are made of engineered ceramic

Because these bearings are so hard, and because their rotational speed is so low, friction is greatly reduced.

Thus, the wheels require no lubricant, which would otherwise attracts grit and eventually cause wear.

The pendulum and escapement mechanism are encased in a shield of quartz glass to keep it free from dust and air movements.

The pendulum itself is made of titanium.  It swings with a period of 10 seconds, making it really the World’s slowest computer.

The Differential Engine

The gears of the Clock form an elaborate system of slots and sliding pins, which much like a Babbage difference engine, will perform the digital calculations required to keep generating the next sequence of 10 bells.

The Babbage Difference Engine

Animation showing a replica of Charles Babbage's Difference Engine N°2 being operated at London Science Museum.In 1822, Charles Babbage completed its first difference engine.

Although the concept of a mechanical calculator for mathematical functions can be traced back to the Antikythera mechanism of the 2nd century BC, this particular device was realised by Babbage.

difference engine is an automatic mechanical calculator designed to tabulate polynomial functions.  It was named after the method of divided differences – a way to interpolate or tabulate functions by using a small set of polynomial coefficients.

Most mathematical functions used by engineers and scientists, including logarithmic and trigonometric functions, can be approximated by polynomials, so a difference engine can compute many useful tables of numbers.

The Babbage engine is in effect the ancestor of the modern computer. 

The Clock keeps calculating the correct time, and performs without electricity using stored energy to move its physical logic gates and bits.  And to save up energy, the dials do not move unless they are physically turned by a visitor.

Powered by Entropy

The Clock is designed to function for 10,000 years, even if no one ever visits it.  It will ring when a visitor winds it, but at times it will ring all by itself.

The Clock hoards energy from various sources.

It uses the energy harnessed by changes in temperatures between day and night to power its time-keeping apparatus.

At the top of the mountain, above it, the diurnal difference of tens of degrees is significant and very powerful.  The differential power is then transmitted to the interior of the Clock by long metal rods.

Although Thermodynamics has previously been used for small mantel clocks before, it has never been achieved on this scale.

In a way, it is our Sun that powers its ringing down below the surface.

As long as the sun shines and night comes, the Clock can keep time itself, without human intervention.  And if the Sun shines through the clouds more often than expected, or if the nights are colder than usual, the excess energy generated by this change will bleed over into the Clock’s weights.

Over time, in ideal conditions, the Sun will continue to wind up the chimes sufficiently for them to ring when no one is there to do so.


Keeping Time Inside The Mountain

For longevity purposes, finding the best 10,000 year environment was perhaps even more critical than the artefact’s material.  Dry, dark and stable temperatures are crucial for its longevity, since freeze-thaw cycles can be just as damaging as water.

The hidden entrance is an opening in the rock face.  A couple of stainless steel doors provide a crude airlock, keeping out the desert dust and wild animals.

Hollowed out of the Texas mountain are five large chambers.  Inside, the temperature remains constant over the seasons, at around 13°C (55°F).

The Clock of the Long Now is hundreds of feet tall.

But if a clock is ringing, and there is no one around to hear it…


Existential Paradox

Astronomical calendars are among the first pieces of culture, and they are often the hallmark of long-vanished civilisations.

The biggest problem for the beating Clock will be its human visitors and their effects upon it.

Over the centuries, valuable stuff of any kind tends to be stolen.  Children climb everywhere.  Hackers eventually try to see how things work or break.

Yet, it is humans that keep the Clock’s bells wound up, and it is humans who ask it the time.

“Such a clock, if sufficiently impressive and well-engineered, would embody deep time for people.  It should be charismatic to visit, interesting to think about, and famous enough to become iconic in the public discourse.  Ideally, it would do for thinking about time what the photographs of Earth from space have done for thinking about the environment.  Such icons re-frame the way people think.”

Stewart Brand,

Writer, inventor, co-founder of The Long Now Foundation

Tick.  1 year.  Tock.  10 years.  Tick, tock.  100 years.  Tick-tock, tick…  1,000 years.  Tick-tock, tick-tock, tick…

Tock…  10,000 years.


10,000 Years More?

The Clock in the mountain fosters long-term thinking in the context of the forthcoming 10,000 years.

“I cannot imagine the future, but I care about it. I know I am a part of a story that starts long before I can remember and continues long beyond when anyone will remember me. I sense that I am alive at a time of important change, and I feel a responsibility to make sure that the change comes out well. I plant my acorns knowing that I will never live to harvest the oaks.”

Danny Hillis,

Clock Designer


“Civilisation is revving itself into a pathologically short attention span.  The trend might be coming from the acceleration of technology, the short-horizon perspective of market-driven economics, the next-election perspective of democracies, or the distractions of personal multitasking.  All are on the increase.”

Stewart Brand (born 1938),

Co-founder of The Long Now Foundation


If we can build a clock that keeps on going for ten millennia, should we not ensure that our civilisation does too?

Time has been ticking for human civilisation.

We are the architects of the Clock.  We may also become the architects of our own destruction.

Overpopulation and our ever growing demand for energy and resources pose an increasing threat to the survival of our species. 

But sometimes, an extinction event does not result from very big events, like a nuclear war.

Forget about the threat of large asteroids skimming past the Earth.

3D animated model showing the SARS-CoV-2 (also known as COVID-19) virus.Sometimes, it’s the little things.  The things we can’t even see.

What we do to our environment matters.

And we are facing new dangers.

Will the Anthropocene really last 10,000 years more?