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[ATM] An Ancient Computer Surprises Scientists
Not quite off topic.
Regards, Vladimir.
November 29, 2006
An Ancient Computer Surprises Scientists
By JOHN NOBLE WILFORD
A computer in antiquity would seem to be an anachronism, like Athena
ordering
takeout on her cellphone.
But a century ago, pieces of a strange mechanism with bronze gears and dials
were recovered from an ancient shipwreck off the coast of Greece. Historians
of
science concluded that this was an instrument that calculated and
illustrated
astronomical information, particularly phases of the Moon and planetary
motions,
in the second century B.C.
The Antikythera Mechanism, sometimes called the world?s first computer, has
now
been examined with the latest in high-resolution imaging systems and
three-dimensional X-ray tomography. A team of British, Greek and American
researchers was able to decipher many inscriptions and reconstruct the gear
functions, revealing, they said, ?an unexpected degree of technical
sophistication for the period.?
The researchers, led by Tony Freeth and Mike G. Edmunds, both of the
University
of Cardiff, Wales, are reporting the results of their study in Thursday?s
issue
of the journal Nature.
They said their findings showed that the inscriptions related to lunar-solar
motions and the gears were a mechanical representation of the irregularities
of
the Moon?s orbital course across the sky, as theorized by the astronomer
Hipparchos. They established the date of the mechanism at 150-100 B.C.
The Roman ship carrying the artifacts sank off the island of Antikythera
around
65 B.C. Some evidence suggests that the ship had sailed from Rhodes. The
researchers speculated that Hipparchos, who lived on Rhodes, might have had
a
hand in designing the device.
In another article in the journal, a scholar not involved in the research,
François Charette of the University of Munich museum, in Germany, said the
new
interpretation of the Antikythera Mechanism ?is highly seductive and
convincing
in all of its details.? It is not the last word, he concluded, ?but it does
provide a new standard, and a wealth of fresh data, for future research.?
Historians of technology think the instrument is technically more complex
than
any known device for at least a millennium afterward.
The mechanism, presumably used in preparing calendars for seasons of
planting
and harvesting and fixing religious festivals, had at least 30, possibly 37,
hand-cut bronze gear-wheels, the researchers reported. An ingenious
pin-and-slot
device connecting two gear-wheels induced variations in the representation
of
lunar motions according to the Hipparchos model of the Moon?s elliptical
orbit
around Earth.
The functions of the mechanism were determined by the numbers of teeth in
the
gears. The 53-tooth count of certain gears, the researchers said, was
?powerful
confirmation of our proposed model of Hipparchos? lunar theory.?
The detailed imaging revealed more than twice as many inscriptions as had
been
recognized from earlier examinations. Some of these appeared to relate to
planetary as well as lunar motions. Perhaps, the researchers said, the
mechanism
also had gearings to predict the positions of known planets.
Dr. Charette noted that more than 1,000 years elapsed before instruments of
such
complexity are known to have re-emerged. A few artifacts and some Arabic
texts
suggest that simpler geared calendrical devices had existed, particularly in
Baghdad around A.D. 900.
It seems clear, Dr. Charette said, that ?much of the mind-boggling
technological
sophistication available in some parts of the Hellenistic and Greco-Roman
world
was simply not transmitted further,? adding, ?The gear-wheel, in this case,
had
to be reinvented.?
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