[Paleopsych] Discover: Time Machine
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Will a clock that works flawlessly for 10,000 years become the
greatest wonder of the world?
By Brad Lemley
DISCOVER Vol. 26 No. 11 | November 2005 | Technology
SOMETIMES, WHEN THINGS GET SUFFICIENTLY WEIRD, SUBTLETY NO
longer works, so i'll be blunt: The gleaming device I am staring at
in the corner of
Prototype number two of the Clock of the Long Now is, at nine feet
tall, a diminutive model of the final version, which is expected to be
at least 60 feet tall and will have multiple displays. This prototype
records the changes in the relative positions of Earth and the five
other planets that humans can eyeball without a telescope. "If you
came up to the clock thousands of years from now, you could still read
the time, even if you did not have the same time system we use now,"
says designer Danny Hillis.
a machine shop in San Rafael, California, is the most audacious
machine ever built. It is a clock, but it is designed to do something
no clock has ever been conceived to do--run with perfect accuracy for
Everything about this clock is deeply unusual. For example, while
nearly every mechanical clock made in the last millennium consists of
a series of propelled gears, this one uses a stack of mechanical
binary computers capable of singling out one moment in 3.65 million
days. Like other clocks, this one can track seconds, hours, days, and
years. Unlike any other clock, this one is being constructed to keep
track of leap centuries, the orbits of the six innermost planets in
our solar system, even the ultraslow wobbles of Earth's axis.
Made of stone and steel, it is more sculpture than machine. And, like
all fine timepieces, it is outrageously expensive. No one will reveal
even an approximate price tag, but a multibillionaire financed its
construction, and it seems likely that shallower pockets would not
Still, any description of the clock must begin and end with that
ridiculous projected working life, that insane, heroic,
incomprehensible span of time during which it is expected to serenely
Ten thousand years.
The span of time from the invention of agriculture to the present.
Twice as long as the Great Pyramid of Giza has stood. Four hundred
Or more to the point, why?
Most humans are preoccupied with the here and now. Albert Einstein,
echoing the sentiments of other deep thinkers of the modern era,
argued that one of the biggest challenges facing humanity is to "widen
our circle of compassion" across both space and time. Everything from
ethnic discrimination to wars, such reasoning goes, would become
impossible if our compassionate circles were wide enough.
That is exactly why W. Daniel Hillis, the man whose insights underlie
the world's most powerful supercomputers, has spent two decades
designing and building
Clock designer Danny Hillis, standing next to an early plywood and
aluminum prototype, knows that looters and vandals pose a significant
threat to his engineering marvel, no matter how well it works. "The
most dangerous period will be the couple of hundred years after I'm
dead, before the clock is really old and assumes historical
importance," he says. "So there will have to be a caretaker. That's
part of the plan."
prototypes of what he has dubbed the Clock of the Long Now. The clock
in the corner of the machine shop, you should understand, is a
prototype, the second prototype. Nonetheless, even the prototype can
tick away for 10,000 years. Hillis and his team just finished it a few
weeks ago. There will be more prototypes over the next few decades
before the final, much larger version is embedded in a mountain in
The clock idea originally sprang from Hillis's observation that in the
1980s, all long-range planning seemed to smack into a wall called the
year 2000--the nice, round number seemed to be the omega point for
everyone from software programmers to international policymakers:
"Nobody could even think about the year 2030. It bugged me." Because
technology began 10,000 years ago--there are pot fragments at least
that old--Hillis decided to build a clock that would tick that long
into the future, conceptually fixing humanity in the center of 20
millennia. Musician Brian Eno, Hillis's friend and a clock project
collaborator, dubbed that vast span "the long now." The clock of his
dreams, said Hillis in 1993, "ticks once a year, bongs once a century,
and the cuckoo comes out every millennium."
The final version, which will be at least 60 feet tall, frankly
strikes more than a few people as pointless. "Many people are
completely uninterested. They think it's nonsense, a waste of time,"
Hillis says. And he concedes that "in the world of ideas, it's an odd
Still, project insiders have found that the idea, like the clock
itself, ticks away patiently, incrementally engaging skeptical minds.
"People will make some flippant comment, then come back months later
with an idea about how to make it work," says Alexander Rose, a
codesigner and executive director of the Long Now Foundation, which
finances the clock.
Hillis, at first motivated by a vague desire to promote long-term
thinking, has been transformed by his idea: "Now I think about people
who will live 10,000 years from now as real people." His eyes take on
a distant focus as he says this, as if he sees them massed on the
horizon. "I had never thought that way before."
But Hillis, who has been known to drive a fire engine to work, also
cautions against regarding the Clock of the Long Now too gravely:
"This project has a lovely kind of lightness to it."
Genius is a shabby, abused, and degraded noun, but Hillis reminds one
of what it should mean. He is cochairman and chief technology officer
of Applied Minds in Glendale, California, a 21st-century analogue of
Thomas Edison's Menlo Park laboratories. There, an elite engineer
corps patents a river of inventions ranging from voice encryptors to
cancer detectors. Universally called Danny, Hillis is affable and
witty but tends to veer abruptly into subjects like lattice theory,
which "describes a piece of graph paper in n dimensions," and from
there the conversation becomes a labyrinth impossible to negotiate.
"Danny's intelligence is the rarest of kinds," says Rose. "The sheer
practicality of his knowledge makes him a true genius."
As an MIT undergrad in 1975, Hillis and his friends built a binary
computer out of 10,000 Tinkertoy pieces. It could beat all comers at
tic-tac-toe. About a decade
A top-down view of a serial-bit adder reveals a cam slider, the long
silvery piece with channels carved in its end, which triggers binary
calculations as it rotates in a carriage over bit pins on a fixed
disk. A 360-degree rotation constitutes one tick of the mechanism. The
clock ticks just twice a day, at noon and at midnight.
later he invented an electronic mainframe computer called the
Connection Machine that worked somewhat like a human brain; instead of
one processor, it had 65,536, all firing at once like buzzing neurons,
a model that supercomputers have used ever since. The irony is
inescapable: The architect of the world's fastest machine now designs
the world's slowest.
The trip to Hillis's office is a cross between a Disney ride and the
multidoor opening sequence of the 1960s television show Get Smart. I
enter a low-slung industrial building, meet Hillis in the lobby,
follow him into a red, British-style phone booth, pick up the
receiver, wait for him to say the password, and follow him through the
false back when it opens into a cavernous workroom. I then pass under
a 13-foot-tall, five-ton, four-legged robot he designed, marvel at his
new invention that instantly makes three-dimensional maps of any place
in the world, then settle into his gadget-strewn office complete with
a New Yorker cartoon of a gypsy behind a crystal ball who says: "Why
ask me about the future? Ask Danny Hillis."
So that's what I do: "How do you build a clock that will keep perfect
time for 10,000 years?"
Hillis, who loves gadgets and was once Walt Disney Imagineering's vice
president for research and development, smiles and begins to explain
HOW STARS TELL US THE TIME
One universal way to visualize the passage of time is to make a
dynamic model of the heavens. The changing relationship of Earth and
the five inner planets can be calculated based on how long it takes
each planet to revolve around the sun, which ranges from 87.97 Earth
days for Mercury to 10759.50 Earth days for Saturn. Here, the diagram
shows the conjunction of the planets on November 15, 2005.
HOW THE CLOCK CAN BE READ
The Clock of the Long Now prototype features an orrery, a simplified
planetary display. The shperical cage of the orrery, called the
firmament, is tilted at 23.27 degrees, the angle of he Earth's axis in
relation to the flat plane of the planets as they radiate out form the
sun. The cage includes a celestial equator with degree markings for
measuring the alignment of the planets at any given time.
challenges involved. The clock must remain accurate for 100 centuries
while sitting on an atmospherically, geologically, and worst of all,
culturally violent planet. To forestall looting (the bane of many
built-for-the-ages projects, such as the Egyptian pyramids), it cannot
contain parts made of jewels and expensive metals. In case of societal
collapse, it must be maintainable with Bronze Age technology. It must
be understandable while intact, so that no one will want to take it
apart. It must be easily improved over time, and it must be scalable
so that the design can be shown via smaller prototypes.
"The ultimate design criterion is that people have to care about it,"
says Hillis. "If they don't, it won't last."
All straightforward, but ludicrously daunting. Time can mean many
things, but Hillis's machine needs to track a particularly messy
version: Earth-surface clock/calendar time, which is based on a
byzantine agglomeration of astronomical rotations, orbits, and
perturbations of hugely varying lengths, overlaid with arbitrary
cultural whims about how to divide it up. What kind of machine can,
for 10 millennia, accurately reconcile hours, days, weeks, months,
leap years, leap centuries, the precession (wobbling around an axis)
of planetary orbits, and, grandest cycle of all, the 25,784-year
precession of the equinox?
Answer: a digital one. A calculation that extends to 28 bits is
accurate to one in 3.65 million--or in clock terms, one day in 10,000
years. Bits and bytes are typically rendered electronically, but
Hillis says he "rejected electronics from the start. It would not be
technologically transparent and probably not durable. I could quickly
see that the clock had to be mechanical."
So Hillis invented--and patented--a serial-bit adder, or a mechanical
binary computer. Instead of using "voltage on" or "voltage off" to
define zeros and ones like a typical electronic computer, the
disk-shaped adder uses levers that can rest in either the "0" or "1"
position. An individual adder can be programmed with 28 pins--what a
programmer would call 28 bits--to represent in binary code any number
displayed by the clock, such as the lunar cycle of 29.5305882 days. A
cam slider with special grooves carved into it spins over the adder's
pins, reading the pins and levers and ticking the levers back and
forth with each revolution until it reaches the desired number and
"overflows." At that point, the slider pops out of the clock's
side--rather like a cuckoo popping out on the hour--and engages a
small wheel, which in turn moves some part of the clock's display. The
clock's guts are a stack of serial-bit adders, each controlling a
different part of the display.
As if that were not complicated enough, the final clock will require a
helical column called the "equation of time" cam. Its purpose will be
to make the
HOW THE CLOCK COMPUTES
The clock is driven by binary mechanical computers called serial-bit
adders with one adder per planet. An adder consists of a disk with an
outer set of bit-pin levers, each of which can take on a value of "1"
or "0," as well as an inner ring of fixed bit pins programmed with a
mathematical constant that represents the duration of the planet's
orbit. (A) The levers and pins are read by a series of channels in a
cam slider that rotates in a carriage. (B) The slider also adds sums
by tripping levers as it goes. (C) During each rotation, the slider
jitters back and forth as it accumulates sums. (D) When the
accumulated sums reach an overflow value, the slider pops out of the
carriage and catches a Geneva wheel. (E) The movement of the Geneva
wheel updates the planetary display.
conversion from absolute time to local solar time. Using a stylus that
traces the cam's rather feminine shape, the clock will be able to
compensate for elliptical eccentricities in Earth's orbit around the
sun and the tilt of Earth's axis. These two celestial phenomena
"beating against each other," as Hillis puts it, produce variations in
the the sun's apparent rate of travel through the sky that would add
up to about 15 minutes per year over the clock's lifetime. (That a
short section of the cam vaguely resembles a nude female's hips and
thighs isn't accidental: Hillis twiddled and tweaked to make the cam
look like that. "Other configurations could have worked, but it would
not have looked nearly as wonderful," he says.)
Still, no mechanical clock, however cleverly crafted, can keep perfect
time for 10,000 years. So Hillis added solar synchronization: A
sunbeam striking a precisely angled lens at noon triggers a reset by
heating, expanding, and buckling a captive band of metal.
And what about power? By harnessing natural processes like temperature
or pressure changes, "there are lots of ways to make it totally
self-winding," says Hillis. "But I want people to engage the clock,
not forget it." So the perfect power system could handle neglect but
would respond to love. The final clock, untended, will wind itself
enough to keep its pendulum swinging and track time, but human
visitors--perhaps by merely stepping on a platform--could also wind
the display. "So when you visit the clock, it shows the last time
someone was there," says Hillis. "When you wind it, it catches up to
now and stops, set for the next person. It rewards attention."
The last question, what to display, gives Hillis the most pause. All
cultures recognize days, months, and years because they spring from
simple "once around" astronomical cycles, but hours, weeks, centuries,
and other divisions are arbitrary, varying wildly across times and
places. Hillis is still mulling how to handle that, but he knows for
sure that the final clock will somehow mirror the positions of the
planets relative to the stars and to one another. "That will be one of
many displays it has," he says.
Hillis is in the process of rolling out these and more ideas in a
series of increasingly complex prototypes. The first one, now on
permanent display at the Science Museum in London, was financed by an
anonymous donor who lent it to
Aside from its eponymous clock, the Long Now Foundation, formed in
1996, pursues projects aimed at promoting "slower, better" thinking:
o The Rosetta Project attempts to preserve all human languages. The
project concentrates on languages that are likely to go extinct by
2100, including hundreds whose native speakers number in the thousands
or fewer. Its document database, representing some 2,300 languages as
of June 2005, is(www.rosettaproject.org) and will be periodically
published in a book and on a micro-etched disk for widespread
o Seminars About Long-Term Thinking, a series of monthly lectures in
various locations around San Francisco, have included such speakers as
geographer Jared Diamond, astronaut Rusty Schweikart, and musician
o The Long Bets Web site (www.longbets.org) lets all comers wager on
long-range predictions (a minimum of two years; there is no maximum),
with proceeds going to a charity named by the victor. For example,
$2,000 is riding on the prediction "By 2030, commercial passengers
will routinely fly in pilotless planes."
the museum. "The deal we offer is, if you fund the next stage of the
development of the clock, we will give you a prototype," says Hillis.
"We have spent millions of dollars so far--I don't know the exact
The nine-foot-tall London clock uses a slowly rotating torsional
pendulum, ticks once every 30 seconds, and tracks hours, sidereal and
solar years, centuries, phases of the moon, and the zodiac--and
happens to be hauntingly beautiful. Incredibly, its three-year-long
construction was completed in a mad rush scarcely one hour before
midnight on December 31, 1999. That meant there was no time to test it
before the switch to the year 2000, the most complex date change in
the Gregorian system since the year 1600 because it involved a
once-in-400-years leap year exemption.
Yet at midnight, "it bonged twice. It was perfect. That was a great
moment," says Hillis softly. "Some people say their millennium
experience was anticlimactic. Mine wasn't."
In his biodiesel-powered Toyota Land Cruiser, Alexander Rose drives me
from the Long Now Foundation's office in the historic Presidio
district in San Francisco across the Golden Gate Bridge to Rand
Machine Works, a metal shop in San Rafael that's about the size of a
three-car garage. In a dark back corner the second prototype is
rising, adder ring by adder ring. It is funded by billionaire Nathan
Myhrvold, former chief technology officer of Microsoft and a longtime
Hillis pal. The clock's builder is Chris Rand, a nonpareil
build-anything machinist who has helped craft everything from the Star
Wars land cruisers to America's Cup yachts. This project, he says, is
working on him.
"I think about everything more long term now," he says.
Someday this clock may become a holy object, but for now it's a
half-finished project in a gritty shop that infidels can touch and
tinker with. I scoot the adder arm around with my index finger. A
complex series of channels cut into its end makes it jitter back and
forth as it slides over pins. The whole thing is so brilliant it makes
me laugh. Gears constitute the heart of the calculation engines of
most other mechanical clocks, but as friction grinds them down, they
get smaller, which means they move faster, which means they lose
accuracy. But an adder's pin--even a worn one--is either there or not
there, at either "1" or "0" until the thing shears clean through,
which in a big clock with massive pins should take more than 10,000
Still, materials remain a tricky question. The prototypes so far have
been made largely of stainless steel, but the metals that will compose
the final clock remain in doubt. "Just about nobody is doing research
on materials that will last for thousands of years," says Rose.
Hillis, Rose, and Rand will make at least one more prototype after
this one, but before Hillis dies, they will build the big one. The
Long Now Foundation made a serious commitment to the final clock
when, in 1999--or, as foundation literature renders this and all other
years, "01999"--it bought 180 acres of desert mountain land adjoining
Great Basin National Park in eastern Nevada. Dry, remote, and
geologically stable, the site has one other serendipitous
attribute--it is studded with bristlecone pines, the world's oldest
living things. At the Long Now Foundation's office, Rose hands me a
core section of a bristlecone on the property. "This is just the outer
trunk, just 1,000 years, from 944 to 2003," he says. Some bristlecones
in the area are nearly 5,000 years old. The clock site may be the only
spot on Earth where commencing a 10,000-year process seems like a
halfway sensible thing to do.
Hillis's plan for the final clock, which he reserves the right to
change, has it built inside a series of rooms carved into white
limestone cliffs, 10,000 feet up the Snake
The Long Now prototype's calculation engine consists of six serial-bit
adders, stacked like pancakes. The long shaft, topped with small
gears, is part of a Geneva wheel mechanism. The clock features six of
these devices. Each one links an individual serial-bit adder to a
large gear that moves a planet in the display.
Range's west side. A full day's walk from anything resembling a road
will be required to reach what looks like a natural opening in the
rock. Continuing inside, the cavern will become more and more
obviously human made. Closest to vast natural time cycles, the clock's
slowest parts, such as the zodiacal precession wheel that turns once
every 260 centuries, will come into view first. Such parts will appear
stock-still, and it will require a heroic mental exertion to imagine
their movement. Each succeeding room will reveal a faster moving and
more intricate part of the mechanism and/or display, until, at the
end, the visitor comprehends, or is nudged a bit closer to
comprehending, the whole vast, complex, slow/fast, cosmic/human,
inexorable, mysterious, terrible, joyous sweep of time and feels
kinship with all who live, or will live, in its embrace.
Or so Hillis hopes.
Some people will no doubt make a pilgrimage to the cavern, but for the
next century at least, that will probably require some commitment, as
the site is "as far as you can get from civilization within the
continental United States," Hillis says. "That will help people forget
about it and avoid the contempt of familiarity."
Most people, however, will never visit the clock, just as most people
never visit the Eiffel Tower. They will only know that it exists. That
knowledge alone will acquaint them with the Long Now, and that is part
of the plan. "When Danny first proposed the clock and I told people
about it, they would say, 'What?' " says Stewart Brand, cochairman of
the Long Now Foundation's board of directors. "Now as I go around,
people come up and say, 'Hey, Stewart, how's the clock coming?' People
are already engaged by it, and it is working on them. It exists before
it exists." Even after it exists, the idea of the clock will no doubt
change more minds than the clock itself.
How much power resides in that deceptively simple idea? Ask yourself
in a month.
For information on the Long Now Foundation and its various projects,
For an image of the prototype on display at the Science Museum in
London as well as more details about the clock's workings, go to
The Clock of the Long Now: Time and Responsibility: The Ideas Behind
the World's Slowest Computer. Stewart Brand. Basic Books, 2000.
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