Episode 15
Antikythera mechanism
Thu, 2017-May-18 01:29 UTC
Length - 3:54
Direct Link
Welcome to popular Wiki of the Day where we read the summary of a popular Wikipedia page every day.
With 1,132,313 views on Wednesday, 17 May 2017 our article of the day is Antikythera mechanism.
The Antikythera mechanism (/ˌæntᵻkᵻˈθiːrə/ ANT-i-ki-THEER-ə or /ˌæntᵻˈkɪθərə/ ANT-i-KITH-ə-rə) is an ancient Greek analogue computer and orrery used to predict astronomical positions and eclipses for calendrical and astrological purposes. It could also track the four-year cycle of athletic games which was similar, but not identical, to an Olympiad, the cycle of the ancient Olympic Games.
Found housed in a 340 millimetres (13 in) × 180 millimetres (7.1 in) × 90 millimetres (3.5 in) wooden box, the device is a complex clockwork mechanism composed of at least 30 meshing bronze gears. Using modern computer x-ray tomography and high resolution surface scanning, a team led by Mike Edmunds and Tony Freeth at Cardiff University peered inside fragments of the crust-encased mechanism and read the faintest inscriptions that once covered the outer casing of the machine. Detailed imaging of the mechanism suggests it dates back to 150-100 BC and had 37 gear wheels enabling it to follow the movements of the moon and the sun through the zodiac, predict eclipses and even recreate the irregular orbit of the moon. The motion, known as the first lunar anomaly, was developed by the astronomer Hipparchus of Rhodes in the 2nd century BC, and he may have been consulted in the machine's construction, the scientists speculate. Its remains were found as one lump, later separated into three main fragments, which are now divided into eighty-two separate fragments after conservation works. Four of these fragments contain gears, while inscriptions are found on many others. The largest gear is approximately 140 millimetres (5.5 in) in diameter and originally had 224 teeth.
The artefact was recovered on May 17, 1902 from the Antikythera shipwreck off the Greek island of Antikythera, which in antiquity was known as Aigila. Believed to have been designed and constructed by Greek scientists, the instrument has been variously dated to about 87 BC, or between 150 and 100 BC, or in 205 BC, or within a generation before the date of the shipwreck (in about 150 BC).
After the knowledge of this technology was lost at some point in antiquity, technological works approaching its complexity and workmanship did not appear again until the development of mechanical astronomical clocks in Europe in the fourteenth century.
All known fragments of the Antikythera mechanism are kept at the National Archaeological Museum in Athens, along with a number of artistic reconstructions of how the mechanism may have looked.
This recording reflects the Wikipedia text as of 01:29 UTC on Thursday, 18 May 2017.
For the full current version of the article, go to http://en.wikipedia.org/wiki/Antikythera_mechanism.
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