One day a Greek archaeologist named Spyridon Stais was carefully
going through some of the material brought up from a shipwreck. The
wreck had been found accidentally two years earlier in 1900 when a
group of sponge divers had been blown off course and forced to
anchor at a new location near the island of Crete at a place called
Antikythera. There the sponge divers started conducting business as
usual. Instead of finding sponges, however, they started bringing up
bits of pottery and other very old artifacts. Amazingly, what the
divers had happened upon was a Roman ship that floundered at sea an
estimated 2000 years earlier.
The Greek government, anxious to recover what they could from the
wreck, had employed the divers to take on the difficult job of
bringing up artifacts from the bottom of the sea using the same
methods they used to search for sponges: free dives with no
breathing apparatus. It was a dangerous business. One diver died and
another was permanently disabled. Still, the group managed to
retrieve a treasure trove of historical objects.
One of the less impressive finds was the lump of material that Stais
was looking at. It appeared to be a mass of wood which was now
decaying since it had been brought to the surface and started drying
out. The rot seemed to have exposed something that Stais hadn't seen
before: a bit of metal. Not just a bit of metal, a bit of metal that
was round with teeth. A gear. Stais couldn't believe his eyes. A
metal gear from a shipwreck before the birth of Christ? What was
What Stais had stumbled upon was the remains of one of the world's
oldest-geared devices - an analog computer - almost two millennia in
age. Over the next century it would upset the archeological world's
understanding about the kind of technology the ancients were capable
Speculations and Reconstructions
After Stais's discovery, speculation about what the device was used
for echoed around the archeological world for decades. Scientists
knew that the device seemed to have 32 interlocking gears and a hand
crank, plus a display that showed information about the moon, sun
and planets against a background of stars. The gears inside the
mechanism were made of bronze and the whole device had apparently
been mounted in a wooden box that measured about 13 inches high, 7
inches wide and 3 ½ inches deep. Unfortunately, much of the device
however had been damaged by its time in the water, making it
difficult to work out exactly how all the parts had been put
Efforts to figure out what the thing actually did received a boost
in 1971 when the mechanism was X-rayed. This enabled scientists to
count the teeth on each gear and then make detailed drawings to
determine how it might have worked. In 1974, Derek de Solla Price, a
historian at Yale University, who had been studying the mechanism
for over twenty years, published a paper showing how he thought the
mechanism operated. Price wrote that the existence of the device
"requires us to completely rethink our attitudes toward ancient
Greek technology." Price also built a reproduction of the device now
housed at the National Museum in Athens.
Much of Price's work, however, was met with skepticism from other
historians who advanced alternate, less-controversial theories. The
existence of a device like the Antikythera Mechanism from this early
a period in history simply did not match many historians'
preconceived notions about the kind of technical expertise the
ancients had. One skeptic, in a desperate attempt to explain how
such a sophisticated object was found in the remains of a Roman
ship, suggested that it was actually a device from the 18th century
that had fallen overboard at some later date and onto the deck of
Recent efforts to find out more about the device have been
spearheaded by the Antikythera Mechanism Research Project, a
consortium of several agencies, businesses and museums
interested in finding out more about the object. The device
was too fragile to be removed from its home at the National
Archaeological Museum of Athens, so the Project constructed
a 12-ton portable micro focus computerized tomographer that
used high resolution X-rays to probe the object and create a
3-dimensional image. Two Hewlett-Packard scientists, also
involved in the project, used a technique they developed
involving a digital camera and fifty different lights to
photograph details of the object that could not previously
be seen. In 2006, the Project announced that with these
tools almost 95 percent of the text engraved on the various
parts of the device is now readable, giving scientists a
much-improved understanding of its capabilities.
Much of what Price and other researchers surmised about the
device seems to be true. The mechanism was clearly an analog
computer designed to allow the operator to predict the
future or past positions of the sun, moon, and probably some
of the planets. On the front of the device were two dials
marked with the zodiac and a solar calendar, with pointers
for the Sun and Moon plus a display showing the phase of the
moon. On the rear of the object was displayed information
about the Saros cycle (a period of around 18 years used in
eclipse prediction) and the Callippic cycle (a period of
about 76 years) using two ingeniously designed spiral dials.
The capability of the machine has amazed scientists. It has
an accuracy of one unit of error out of 860000. One
researcher, Professor Mike Edmonds remarked, "This device is
just extraordinary, the only thing of its kind. The design
is beautiful, the astronomy is exactly right. The way the
mechanics are designed just makes your jaw drop. Whoever has
done this has done it extremely carefully."
Price's reproduction of the Mechanism
(National archaeological museum, Athens/Wikipedia Commons)
Built by Aliens?
built this ingenious device? Some have gone so far as to suggest it
was the work of aliens. There is no real evidence for this, of
course, and historical texts do have references to devices similar
in design to the Antikythera Mechanism. The Roman historian Cicero
wrote about a device supposedly constructed by the Greek philosopher
Archimedes which was brought back to Rome by the Roman general
Marcus Claudius Marcellus after he conqured Syracuse in 212 BC.
According to Cicero, he received a demonstration of the device from
a descendant of Marcellus and the object displayed the motions of
the sun, moon and five planets. Cecero also mentions that a similar
device was built by his friend Posidonius, another Greek philospher.
A millenium later the Persian scholar al-Biruni also described a
device similar to the Antikythera Mechanism and included a diagram
of it in a treatise written in AD 996. Though it was much simpler in
design, historians have speculated that the object in the diagram
was a direct descendant of the Antikythea device.
Price had a theory that the Antikythera Mechanism was constructed by
the Greek astronomer Geminus on the Greek island of Rhodes around 87
BC. At the time the island was a center of learning for astronomy
and mechanical engineering. Engineers there were well-known for
creating intricate automata (mechanical toys or tools that
demonstrated basic scientific principles). The device could have
found its way on board a Roman ship a decade later as part of a
hoard of treasure being taken to Rome to be displayed in a triumphal
parade for Julius Caesar.
How was it used?
This remains a matter of great speculation. Such a device would have
been of great help to an astrologer in creating star charts. It
could have also been used to correct calendars and set the dates of
religious festivals. It might even have provided assistance in
predicting what days eclipses were likely to occur.
We may never know exactly who built it or what it was used for.
However, it remains a testament to the engineering skills of the
ancients and a warning that despite all we know about history, there
are still mysteries to be solved.