Antikythera mechanism
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What is the Antikythera mechanism?
The Antikythera mechanism is an ancient Greek device that calculated and displayed astronomical information. It was recovered in 1901 from a trading ship that sunk in the Mediterranean Sea near Antikythera.
Dating back to 100 BCE, this device, sometimes called the first known computer, featured the earliest known scientific dials and scales. Radiographic images revealed that the fragments contained 30 gear wheels, an unprecedented complexity for its time, not seen again until medieval cathedral clocks.
Housed in a shoebox-sized case, the mechanism, made of bronze, used a hand-turned shaft to drive gear trains. Dials displayed the positions of the Sun and Moon, lunar phases, the Metonic cycle of 235 lunations over 19 years, and even indicated the timing of the Olympic Games. It also predicted solar and lunar eclipses using the saros eclipse cycle.
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Where and when was the Antikythera mechanism discovered?
The Antikythera mechanism was discovered in 1901 in the Mediterranean Sea near the island of Antikythera. It was retrieved from a trading ship that sank in the first half of the 1st century BCE.
This ancient Greek mechanical device, now housed in the National Archaeological Museum in Athens, is believed to have been manufactured around 100 BCE. It served as an ancient "computer" used to calculate and display information about astronomical phenomena.
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What was the main purpose of the Antikythera mechanism?
The Antikythera mechanism, discovered in 1901, is an ancient Greek device used to calculate and display astronomical information. It dates back to 100 BCE and features the earliest known scientific dials and scales. The device, made of bronze, was housed in a shoebox-sized case with inscriptions explaining its calendrical purpose. It could show the positions of the Sun and Moon, lunar phases, and predict solar and lunar eclipses using the Metonic and Saros cycles. The mechanism also indicated the timing of Panhellenic Games, including the Olympics.
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How did the gears inside the Antikythera mechanism work?
The Antikythera mechanism, an ancient Greek device dating back to 100 BCE, is the oldest known complex geared mechanism. It was made from bronze sheets and originally housed in a shoebox-sized case. The device featured a hand-turned shaft connected to a main gear wheel, which, with each revolution, corresponded to a solar year. This main gear drove further gear trains.
On the front, dials displayed the positions of the Sun and Moon in the zodiac, along with lunar phases. The lunar drive train incorporated sophisticated epicyclic gearing and a slot-and-pin mechanism to replicate variations in the Moon's motion. The back featured dials indicating the 235 lunations in the Metonic cycle and predicted solar or lunar eclipses based on the 18.2-year saros cycle.
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Why is the Antikythera mechanism considered important in the history of technology?
The Antikythera mechanism is considered an important artifact in the history of technology because it is the first known complex geared mechanism used to calculate and display astronomical information. Recovered from a shipwreck in 1901, its manufacturing is dated around 100 BCE. The device contained 30 gear wheels, a level of complexity unmatched until medieval cathedral clocks were built a millennium later. The mechanism could display the positions of the Sun and Moon, lunar phases, the Metonic cycle, and predict solar and lunar eclipses. It is the only known physical evidence of a tradition of mechanical astronomical displays in the ancient world.
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Antikythera mechanism, ancient Greek mechanical device used to calculate and display information about astronomical phenomena. The remains of this ancient “computer,” now on display in the National Archaeological Museum in Athens, were recovered in 1901 from the wreck of a trading ship that sank in the first half of the 1st century bce near the island of Antikythera in the Mediterranean Sea. Its manufacture is currently dated to 100 bce, give or take 30 years.
The Antikythera mechanism had the first known set of scientific dials or scales, and its importance was recognized when radiographic images showed that the remaining fragments contained 30 gear wheels. No other geared mechanism of such complexity is known from the ancient world or indeed until medieval cathedral clocks were built a millennium later.
The Antikythera mechanism was fabricated out of bronze sheet, and originally it would have been in a case about the size of a shoebox. The doors of the case and the faces of the mechanism are covered with Greek inscriptions, enough of which survive to indicate clearly much of the device’s astronomical, or calendrical, purpose. It is believed that a hand-turned shaft (now lost) was connected by a crown gear to the main gear wheel, which drove the further gear trains, with each revolution of the main gear wheel corresponding to one solar year. On the front of the mechanism is a large dial with pointers for showing the position of the Sun and the Moon in the zodiac and a half-silvered ball for displaying lunar phases. The drive train for the lunar position is extremely sophisticated, involving epicyclic gearing and a slot-and-pin mechanism to mimic subtle variations (known as the “first anomaly”) in the Moon’s motion across the sky. (See Hipparchus and Ptolemaic system.)
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Two large dials are on the back of the mechanism. The large upper dial has a five-turn spiral slot with a moving pointer to show the 235 lunations, or synodic months, in the Metonic cycle. This cycle is almost exactly 19 years long and is useful in regulating calendars. A subsidiary four-year dial showed when the various Panhellenic games should take place, including the ancient Olympic Games. The large lower dial has a four-turn spiral with symbols to show months in which there was a likelihood of a solar or lunar eclipse, based on the 18.2-year saros eclipse cycle. These astronomical cycles would have been known to the Greeks from Babylonian sources. The inscriptions imply that there may originally have been a display of planetary positions, most likely on the front face, but nearly all the relevant parts are missing.
The Antikythera mechanism is the only known physical survivor of a long tradition of mechanical astronomical displays. The widespread existence of such devices can be inferred from references in Greco-Roman literature, particularly in the descriptions left by Marcus Tullius Cicero (1st century bce), that stretch from Archimedes (3rd century bce) to a poetic reference in the late 4th or early 5th century ce. The exact purpose of the Antikythera mechanism remains speculative, however. Nor is it known if the bronze-geared technology and the advanced mechanical design skills involved in its construction were exploited for other applications within the Greco-Roman world.
The Antikythera Mechanism Research Project, under the aegis of Greece’s Hellenic Ministry of Culture, supports an international collaborative effort by academic researchers to study the Antikythera mechanism.