10,000-year clock under construction inside mountain in Culberson County

By Kevin Kelly —

The Long Now Foundation

There is a clock ringing deep inside a mountain. It is a huge clock,
hundreds of feet tall, designed to tick for 10,000 years. Every once in a
while the bells of this buried clock play a melody. Each time the chimes
ring, it's a melody the clock has never played before.

The clock's chimes have been programmed to not repeat themselves for
10,000 years.Most times the clock rings when a visitor has wound it, but
the clock hoards energy from a different source and occasionally it
will ring itself when no one is around to hear it. It's anyone's guess
how many beautiful songs will never be heard over the clock's 10
millennial lifespan.

The clock is real. It is now being built inside a mountain in West
Texas, near Van Horn. This clock is the first of many millennial clocks
the designers hope will be built around the world and throughout time.
There is a second site for another clock already purchased at the top of a
mountain in eastern Nevada, a site surrounded by a very large grove of
5,000-year-old bristlecone pines.

Appropriately, bristlecone pines are among the longest-lived
organisms on the planet. The designers of the clock in Texas expect its
chimes will keep ringing twice as long as the oldest 5 millennia-old
bristlecone pine. Ten thousand years is about the age of civilization,
so a 10,000-year clock would measure out a future of civilization equal
to its past. That assumes we are in the middle of whatever journey we
are on – an implicit statement of optimism.

The clock is now being machined and assembled in California and
Seattle. In the meantime, the mountain in Texas is being readied. Why
would anyone build a clock inside a mountain with the hope that it will
ring for 10,000 years?

Part of the answer: just so people will ask this question, and having
asked it,prompt themselves to conjure with notions of generations and
millennia. If you have a clock ticking for 10,000 years what kinds of
generational-scalequestions and projects will it suggest? If a clock can
keep going for ten millennia, shouldn't we make sure our civilization
does as well? If the clock keeps going after we are personally long
dead, why not attempt other projects that require future generations to
finish? The larger question is, as virologist Jonas Salk once asked,
“Are we being good ancestors?”

The clock is designed by Danny Hillis, a polymath inventor, computer
engineer, and designer, inventor and prime genius of the clock. He and
Stewart Brand, acultural pioneer and trained biologist, launched a
non-profit foundation to build at least the first clock. Fellow traveler
and rock musician Brian Enonamed the organization The Long Now
Foundation to indicate the expanded senseof time the clock provokes –
not the short now of next quarter, next week, or the next five minutes,
but the “long now” of centuries.

Eno also composed the never-repeating melody generator that rings the clock's chimes inside the mountain. Other people unhappy with our
society's short-attention span are part of this group, including me, one
of its charter officers. This clock in the Mountain is being funded and
built on property owned by Jeff Bezos, the founder and CEO of
amazon.com. Bezos is also active in designing the full experience of the

The first step in this multi-decade project was to construct a
working 8-foot-tallprototype. This test version was finished on New
Year's Eve 1999. At the stroke of midnight, the prototype 10,000-year
clock bonged twice to usher in the new millennia, the year 2000, in
front of a small crowd at its temporary home in the Presidio in San
Francisco. The clock now resides in the London Science Museum. Somewhat
worrisome, there have been moments when it was not wound.

In contrast to the human-scale of the prototype, the clock in the
mountain will be monumental, almost architectural in scale. It will be
roughly 200 feet tall. Located under a remote limestone mountain near
Van Horn, Texas, it will require a day's hike to reach its interior
gears. Just reaching the entrance tunnel situated 1,500 feet above the
high scrub desert will leave some visitors out of breath, nicked by
thorns, and wondering what they got themselves into.

To see the clock you need to start at dawn, like any pilgrimage. Once
you arrive at its hidden entrance in an opening in the rock face, you
will find a jade door rimmed in stainless steel, and then a second steel
door beyond it. These act as a kind of crude airlock, keeping out dust
and wild animals. You rotate its round handles to let yourself in, and
then seal the doors behind you. It is totally black. You head into the
darkness of a tunnel a few hundred feet long. At the end there's the
mildest hint of light on the floor. You look up. Thereis a tiny dot of
light far away, at the top of top of a 500-foot long vertical tunnel
about 12 feet in diameter. There is stuff hanging in the shaft.

The dot of light beckons you. You begin the ascent. You start
climbing a continuous spiral staircase, winding up the outer rim of the
tunnel, rising toward the very faint light overhead. The stairs are
carved out of the rock. The material above each step has been removed
from the tunnel leaving astoundingly precise rock stairs. To cut the
spiral staircase Stuart Kendall of Seattle Solstice invented a special
stone slicing robot to continuously grind out the stairs at the rate of a
few stairs per day. His robot incrementally creeps downward while the
debris falls into the central shaft out of the way.

Round the tunnel and up the tube toward the light you head. The first
part of the clock you encounter on the ascent up the spiral staircase
is the counterweights of the clock's drive system. This is a huge stack
of stone disks, about the size of a small car, and weighing 10,000
pounds. Depending on when the clock was last wound, you may have to
climb 75 feet before you reach the weights.

After you pass the weights, you arrive at the winding station. It is a
horizontal windlass, or a capstan like the turnstile on an old sailing
vessel that winds up an anchor. It takes two or three visitors to push
around the capstan of the clock and to lift its 10,000-pound stones. You
rotate around until you can no further. Now the clock is wound.

You keep climbing. For the next 70-80 feet of ascent, you pass 20
huge horizontal gears (called Geneva wheels), 8 feet in diameter, each
weighing 1,000 pounds. This isthe mechanical computer that calculates
the over 3.5 million different melodies that the chimes will ring inside
the mountain over the centuries. The chimes never repeat so that every
visitor's experience is unique, and the calculated variety creates a
sense of progressive time, rather than endless recycling.

And “calculate” is the correct word, because cut into the gears is an
elaborate system of slots and sliding pins, which, much like a Babbage
Difference Engine,will perform digital calculations, generating the next
sequence of the ten bells. Only the clock calculates without
electricity, using your stored energy to moving its physical logic gates
and bits. This is the world's slowest computer.

On days when visitors are there to wind it, the calculated melody is
transmitted to the chimes, and if you are there at noon, the bells start
ringing their unique one-time-only tune. The 10 chimes are optimized
for the acoustics of the shaft space, and they are big.

Finally,way out of breath, you arrive at the primary chamber. Here is
the face of the clock.A disk about 8 feet in diameter artfully displays
the natural cycles of astronomical time, the pace of the stars and the
planets, and the galactic time of the Earth's procession. If you peer
deep into the clock's workings you can also see the time of day.

But in order to get the correct time, you need to “ask” the clock.
When you first come upon the dials the time it displays is an older time
given to the last person to visit. If no one has visited in a while,
say, since 8 months and 3days ago, it will show the time it was then.

To save energy, the clock will not move its dials unless they are
turned, that is, powered, by a visitor. The clock calculates the correct
time, but will only display the correct time if you wind up its display
wheel. So yet another hand-turned wheel awaits your effort to update
the face of time. This one is much easier to wind because the dial
motion consumes less power than ringing bells. You start winding and the
calendar wheels whir until BING, it stops and it shows the current date
and time.

So how does the clock keep going if no one visits it for months, or
years, or perhaps decades? If it is let to run down between visits, who
would keep resetting it? The clock is designed to run for 10,000 years
even if no one ever visits (although it would not display the correct
time till someone visited).If there is no attention for long periods of
time the clock uses the energy captured by changes in the temperature
between day and night on the mountaintop above to power its time-keeping

In a place like a top of a mountain, this diurnal difference of tens
of degrees in temperature is significant and thus powerful. Thermal power
has been used for small mantel clocks before, but it has not been done
before at this scale. The differential poweris transmitted to the
interior of the clock by long metal rods. As long as thesun shines and
night comes, the clock can keep time itself, without human help.But it
can't ring its chimes for long by itself, or show the time it knows,
so it needs human visitors.

If the sun shines through the clouds more often than expected, and if
the nights are colder than usual, the extra power generated by this
difference (beyond what is ordinarily needed to nudge the pendulum) will
bleed over into the clockweights. That means that over time, in ideal
conditions, the sun will actually wind up the chimes, and wind them up
sufficiently for them to ring when no one is there.

The rotating dials, gears, spinning governor, and internal slips of
pins and slots within the clock will be visible only if you bring your
own light. The meager dot of light above is not sufficient to see much
otherwise. Lights off, the clock sits in near total darkness, talking to
itself in slow clicks, for perhaps years at a time. In the darkness you
can hear things moving, crisp non-randompings, like a crude thought
trying to form inside a dim unlit brain.

Shining your light around the rest of the chamber you'll see the
pendulum and escapement encased in a shield of quartz glass – to keep
out dust, air movements, and critters. The pendulum, which governs the
timing of the clock,is a 6-feet-long titanium assembly terminating with
football-sized titanium weights. It swings at a satisfyingly slow
10-second period. The slight clicks of its escapement echo loudly in the
silence of the mountain.

Building something to last 10,000 years requires both a large dose of
optimism and a lot of knowledge. There's a huge geek-out factor in the
clock because the engineering challenges are formidable. What do you
build with that won't corrode in 100 centuries? How do you keep it
accurate when no one is around? The clock's technical solutions are
often ingenious.

Almost any kind of artifact can last 10 millennia if stored and cared
for properly. We have examples of 5,000-year-old wood staffs, papyrus,
or leather sandals. On the other hand, even metal can corrode in a few
years of rain. For longevity,  a 10,000-year environment is more
important than the artifact's material. The mountain top in Texas (and
Nevada) is a high dry desert, and below, in the interior tunnel, the
temperature is very even over seasons and by the day (55degrees F) –
another huge plus for longevity since freeze-thaw cycles are as
corrosive as water. Dry, dark and stable temperatures are what
archivists love.It's an ideal world for a ceaseless clock.

Still, the clock is a machine with moving parts, and parts wear down
and lubricants evaporate or corrode. Most of the clock will be made in a
marine grade 316 stainless steel. Because the engineering tolerances of
the huge clock are infractions of an inch, rather than thousandths, the
microscopic expansion by a film of rust won't hurt the time keeping.
The main worry of the clockmakers is that elements of a 10,000-year
clock — by definition — will move slowly. The millennial dial creeps so
slowly it can be said to not move at all during your lifetime.

Metals in contact with each other over those time scales can fuse –
defeating the whole purpose of an ongoing timepiece. Dissimilar metals
in contact can eat each other in galvanic corrosion. To counteract these
tendencies some of the key moving parts of the clock are non-metal —
they are stone and hi-tech ceramics.

Ceramics will outlast most metals. We have found shards of clay pots
17,000 years old. And modern ceramics can be as hard as diamonds. All
the bearings in the clock will be engineered ceramic. Because these
bearings are so hard, and rotate at very low speed, they require no
lubrication – which normally attracts grit and eventually cause wear.

There is more than just technology in the mountain. The ticks of time
are a very human invention. Astronomical calendars are among the first
pieces of culture,and often the mark of civilizations. The cave holds
culture. The clock in the mountain not only plays the music of an
ever-changing slow melody, but it will collect cultural expressions of
time, ticks to mark the passage of decades and centuries. Off to the
side of the main cavern of the clock are a series of small grottos to
explore and collect these notices of time. Their contents will be a

Behind the main chamber's dials the stairs continue up to the outside
summit of the mountain. The shaft above clock continues to the surface,
where its opening to the daylight is capped with a cupola of sapphire
glass. This is the only part of the clock visible from outside, on the
mountain peak.

In this outdoor cupola sits the thermal-difference device to power
the timekeeping, and also a solar synchronizer. Every sunny noon, a
prism directs sunlight down the shaft and slightly heats up this
ingenious mechanical device.That synchronizing signal is transmitted by
rods further down to the clock's innards, where the imperceptible
variations in the length of the day as the earth wobbles on its axis
will be compensated so that the clock can keep its noon on true solar
noon. In that way, the clock is self-adjusting, and keeps good time over
the centuries.

The journey to the clock in the mountain ends on the summit in light.
It is the sun that powers its ringing below. Like a heart beating while
we sleep, the clock in the mountain keeps time even when we pretend the
past did not happen and the future will not come.

The biggest problem for the beating clock will be the effects of its
human visitors. Over the span of centuries, valuable stuff of any type
tends to be stolen, kids climb everywhere, and hackers naturally try to
see how things work or break. But it is humans that keep the clock's
bells wound up, and humans who ask it the time. The clock needs us. It
will be an out of the way, long journey to get inside the clock ringing
inside a mountain. But as long as the clock ticks, it keeps asking us,
in whispers of buried bells, “Are we being good ancestors?”


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