the antikythera mechanism...reason, the international scientific community recognizes these models...

The Antikythera MechanismHistorical Mechanical Engineering Landmark

Athens, National Archaeological MuseumThe American Society of Mechanical Engineers

Visit us at : www.namuseum.grwww.TheAntikytheraMechanism.com

The research team of ThessalonikiThe Antikythera Mechanism Research Team of Aristotle’sUniversity of Thessaloniki (AUTH) and the University ofMacedonia of Thessaloniki (UOM), has constructed accurateand functional copies of the Mechanism. These are entirelybased on those portions of the research team’s findings thathave been accepted by the international scientific communitythrough publications in reliable scientific journals. Thesemodels include all the latest revelations, but do not includeanything that has not been scientifically proven. For thatreason, the international scientific community recognizes thesemodels as the most accurate and reliable constructed to date.

John Hugh Seiradakis :Emeritus Professor,Department of Physics, AUTHEfstathiou Kyriakos :Professor, Department of Mechanical Engineering, AUTHRoumeliotis Manos :Professor, Department of Applied Informatics, UOMAnastasiou Magdalini :Doctor, Physicist, AUTH

Efstathiou Marianna :Doctor, Mechanical Engineer, AUTHBasiakoulis Alexandros :MSc, Mechanical Engineer, AUTHTourtas Alexandros :Doctor, Archaeologist, Scientific DiverAnastasovitis Leyteris :PhD candidate, Department of Applied Informatics, UOM

SETTING THE STANDARD

Copyright © Ministry of Culture and Sports/ArchaeologicalReceipts Fund

National Archaeological Museum Photographic Archive:front page photo, page 3, page 6 (radiograph), page 8 (left photo),page 16, page 23 (upper photo)

Brochure design : Dr. M. Efstathiou, A. Basiakoulis

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It provides an annotated roster for engineers, students,educators, historians and travelers. It also providesreminders of where we have been and where we aregoing along the divergent paths of discovery.ASME helps the global engineering community developsolutions to real world challenges. ASME, founded in1880, is a not-for-profit professional organization thatenables collaboration, knowledge sharing and skilldevelopment across all engineering disciplines, whilepromoting the vital role of the engineer in society. ASMEcodes and standards, publications, conferences,continuing education and professional developmentprograms provide a foundation for advancing technicalknowledge and a safer world.ASME OFFICERSSaid Jahanmir, PresidentThomas Costabile, P.E., Executive Director/CEO

ASME HISTORY AND HERITAGE COMMITTEEHerman H. Viegas, P.E, (Ret.) ChairTerry S. Reynolds, Vice ChairLee S. Langston, SecretaryMarco CeccarelliThomas H. Fehring, P.E., Immediate Past ChairRichard I. Pawliger, P.E., (Ret) Past ChairRobert T. Simmons, P.E., Past President

Corresponding MembersJohn K. BrownScott Davidson, P.E. (Ret.)Martin C. RossVirginia RossSteven WaltonRobert O. Woods, P.E. (Ret.)Emeritus MembersJ. Lawrence Lee, P.E., Past ChairRobert M. VogelASME STAFFRoger Torda, manager, Communications Projects & InitiativesWil Haywood, Communications Specialist

Athens, National Archaeological Museum The American Society of Mechanical Engineers

The story behind the mystery

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The history and heritage program of ASME

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Since the invention of the wheel, mechanical innovationhas critically influenced the development of civilizationand industry as well as public welfare, safety and comfort.Through its History and Heritage program, the AmericanSociety of Mechanical Engineers (ASME) encouragespublic understanding of mechanical engineering, fostersthe preservation of this heritage and helps engineersbecome more involved in all aspects of history. In 1971ASME formed a History and Heritage Committeecomposed of mechanical engineers and historians oftechnology. This Committee is charged with examining,recording and acknowledging mechanical engineeringachievements of particular significance. For furtherinformation, please visit http://www.asme.org.

Landmark designationsThere are many aspects of ASME's History and Heritageactivities, one of which is the landmarks program. Sincethe History and Heritage Program began, 270 artifactshave been designated throughout the world as historicmechanical engineering landmarks, heritage collections orheritage sites. Each represents a progressive step in theevolution of mechanical engineering and its significanceto society in general. The Landmarks Program illuminatesour technological heritage and encourages thepreservation of historically important works.

Recovered in 1901 from a first-centuryBC shipwreck, the AntikytheraMechanism is the oldest extantcomplex geared device. It isessentially an analog computer, aninscribed astronomical and calendricaldevice, designed to predictastronomical phenomena such aslunar and solar eclipses, to maintaincalendar accuracy and to predict thedates of Panhellenic Games. Themechanism’s miniature scale, theelaborate gear trains, the use ofdifferential and epicyclic gears, andthe employment of pin-and-slotcouplings demonstrate that the Greekmechanicians of the Hellenistic periodhad become far more fluent indesigning geared devices than thesurviving written sources infer.Geared devices matching thecomplexity of the Antikytheramechanism would not appear again inEurope until the mechanical clocks ofthe thirteenth century.


Construction of the Antikythera Mechanism2nd c. BC

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Museum in Athens (Gallery 38), accompanied byexplicative texts, models and audiovisual material. TheAntikythera Mechanism consisted of at least 30 gearwheels with teeth, as well as dials, axles and pointers,made of at least three different alloys of copper, tin andlead. The astronomical inscriptions on the interior surfaceof the Μechanism referred to astronomical and dailycalculations, while those on the front and back platesconvey information and instructions for the Device’s use.The Greek inscriptions are carved by the same hand anddate the device in the 2nd c. BC. Housed in a rectangularframe the device shows data on both sides. TheMechanism was probably constructed on the GreekIsland of Rhodes, but we cannot be sure about the placeor the manufacturer. In the period it was likelyconstructed, one of the greatest astronomers ofantiquity, Hipparchus, lived on Rhodes.

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The movement of the Moon is not circular but elliptical.The Mechanism’s display of this movement takes intoaccount the anomaly caused by its eccentric orbit aroundthe Earth by using two eccentric gears, the axes of whichare separated by 1.1 mm. The lower gear has a pin thatengages with a slot on the upper gear, forcing it to rotateelliptically. The epicyclical movement of the upper geartracked the motion of the Moon in the sky with greataccuracy.

Eccentric gears system

(Pin and Slot)

The epicyclical motion of the moon

Pin

Slot

Τhe 82 fragments of theAntikythera Mechanism(NAM Inv. No. X 15087)are exhibited in thepermanent exhibition ofthe Collection ofMetalworks of theΝational Archaeological


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A Roman ship wrecked in the 1st century BC yieldednumerous statues, vases, coins, and other artifacts,some dating back to the 4th century BC. Among them,were the severely corroded fragments of the world'soldest known analog computer, the AntikytheraMechanism. The ancient works of art, including parts ofthe ship itself, are now displayed at the NationalArchaeological Museum in Athens.

The Roman shipwreck

75 – 50 BCThe gears

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The gears found on the Antikythera Mechanism are theearliest known to resemble the shape and design ofmodern gears. Their triangular teeth were designed totransmit angular motion, not power. The Mechanismcontained at least 39 interacting gears, among whichwere two crown gears. 30 of the gears were extant inthe fragments of the Mechanism and others have beeninferred, taking into account their probable use incalculating astronomicalphenomena. The Mechanismincluded 7 pointers with 8displays. The moon’s pointerdisplayed two phenomena: theposition of the moon in the skyand the phase of the moon. Arotating sphere, linked by acrown gear to the Moon’spointer, displayed the phases ofthe Moon.


at depths between 40 and 50 m. In November of 1900,sponge boat captain Dimitrios Kontos alerted theauthorities in Athens to the discovery. Instantly theHellenic Royal Navy vessel "Mykali" was dispatched to theisland to support the excavation, followed soon by thecivilian steam ship "Syros” and later the Navy torpedo boat"Aigialeia". It was the first coordinated underwaterexcavation in history. In 1976 an excavation of theshipwreck was undertaken by the Ephorate of UnderwaterAntiquities in collaboration with Jacques Yves Cousteauand his oceanographic ship “Calypso”. The underwaterinvestigation continued under the supervision of theArchaeological Service in 2010s’. In 2012 the NationalArchaeological Museum organized a temporary exhibitiondedicated to the “Antikythera Shipwreck”. Almost all thefinds were presented in their context for the first time (seeN. Kaltsas, El. Vlachogianni, P. Bouyia (eds.), TheAntikythera Shipwreck, the ship, the treasures, themechanism, April 2012 – April 2013, NationalArchaeological Museum, Athens 2012).

The discovery and the excavation1900– 1901

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A subsidiary Exeligmos dial, within the Saros dial,extended the eclipse prediction capabilities to threeSaros cycles, indicating that 8 and 16 hours should beadded respectively in the second and third Saros cycles tothe eclipse times indicated by the inscriptions.

The back side - The “Exeligmos dial”

In the spring of 1900, twosponge fishing boats from theGreek island of Symi came tothe east coast of AntikytheraIsland, where diver IliasStadiatis discovered the wreck


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Karakalos' X-rays and Price's Book

1970– 1974

Many researchers studied the Mechanism from 1902until 1970. Beginning in 1970, Derek J. de Solla Price ofYale University and nuclear physicist CharalamposKarakalos used gamma-rays and x-rays to see inside thecorroded fragments. The images they secured showedseveral gears, along with dials and plates, some coveredwith inscriptions. Using these data, Robert J. Deroski,under the supervision of Price, constructed two models.

The back side - The spiral of Saros

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The lower back dial is a Saros eclipse-prediction dial,arranged as a four-turn spiral of 223 lunar months, withglyphs indicating eclipse predictions.Within each period of 223 lunar months, known as theSaros cycle, eclipses are repeated with the same intervalsand characteristics.


("Gears from the Greeks"), Professor Manos Roumeliotis(University of Macedonia in Thessaloniki) designed thefirst simulation of the Antikythera Mechanism andprovided access to everyone! For the first time since theAntikythera Mechanism had been “rediscovered”,anyone could download an interactive simulation and"explore" the Mechanism by rotating, zooming, and evenchanging the speed of the gears' rotation.

The first computer simulation

1998

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The back side - The “Callippic dial”

Calippos, a 4th century BC astronomer who lived afterMeton, discovered that Meton had made a small mistakein his calendric system. Every 4 periods of Meton, i.e.,every 76 years, one day needed to be removed. TheCallippic pointer indicated when the correction must takeplace.

1990 - 2005

Based on Derek J. deSolla Price's book

M. Wright’s modelIn 1990, A.G. Bromleycollaborated with M. Wright,using X-Rays to determinethe exact position of thegears inside the Mechanism, but their research didn’tgive the expected results. After Bromley’s sudden death,Wright continued the research on his own, suggestingand constructing in 2005, a model with pointers not onlyfor the Moon and the Sun, but also for the five planetsknown in antiquity.


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The "Blade Runner”and the "PTM Dome"

2005

2005 was one of the most important years forAntikythera Mechanism research. Two world-class hightechnology companies, Hewlett Packard and X-TekSystems, applied two new technologies to unravel themystery of the Mechanism: the "PTM-Dome" and the"Blade Runner" respectively. PTM-Dome was a devicethat made it much easier to read the letters on thesurface of the fragments by using a digital imagingtechnique. Blade Runner was an eight-ton x-raytomograph that could "read" the inside of theMechanism. Both techniques revealed a huge amount ofpreviously unknown data, and for the first time theMechanism was completely unlocked! The next step wasto interpret all this data. A new chapter for theAntikythera Mechanism had just begun!

The back side - The Panhellenic “CrownGames” dial

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A subsidiary dial within the upper back spiral of theAntikythera Mechanism displayed the celebration date ofthe important ancient Panhellenic “Crown Games”. Onthe circumference of the dial the words Olympia, Pythia,Isthmia, Nemea and Naa have been deciphered.Internally, in each quadrant, the four years of theOlympic cycle are indicated. In all these “Crown Games”the winners were being awarded with wreaths.


The first attempt of Aristotle's University of Thessaloniki(Greece) to build a functional copy of the Mechanism wassupervised by Professors K. Efstathiou (School ofMechanical Engineering) and J. H. Seiradakis (School ofPhysics). The model was based on a 2006 article in thejournal “Nature”, but it turned out not to be functional.The problem was identified as being due to the gears‘measured dimensions and axial distances, as reported in“Nature”. After more than 2000 years at the bottom ofthe sea, the Mechanism’s fragments had becomefossilized, and all the components had been shifted. Thedata from “Nature” might have accurately reflected theposition and dimensions of the gears in the recovereddevice, but the fragments had been so corrupted byseveral thousand years of corrosion that a functionalmodel could not be built to those specifications.

First model of Aristotle’s University of Thessaloniki

2008

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At the subdivisions of the spiral, the ancient names of12 lunar months are artistically carved, repeated toform a period of 19 years. The names of the monthsare of Corinthian origin, reflecting those used by theCorinthian colonies of northwestern Greece.


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Second model of Aristotle’s University of Thessaloniki

2011

Right after the first, non-functional, model in 2008,Aristotle’s University of Thessaloniki began a whole newresearch project, to determine all gears' diameters, theaxial distances, and possible construction methods of theoriginal Mechanism. The goal was to design all themechanical parts from scratch (axial distances, position,and diameters of the gears), in order to construct afunctional device as similar as possible to thetomographs. The result was a brand new functionalmodel with more than 97% of the mechanical parts andtheir dimensions identical to the fragments! The goal hadbeen completed!

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On the back side of the Antikythera Mechanism, therewere two main dials in the form of spirals. The upperback dial is a 19-year calendar, arranged as a five-turnspiral of 235 lunar months. This calendar is known asthe Metonic cycle, named after the Greek astronomerMeton of Athens who lived in the 5th century BC andhad observed that every 19 solar years the Moonreturned to the same point in the sky with the samephase.

The back side - An ancient calendar


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The two concentric dials

The Moon’s pointer and its sphere

The Moon’s pointer crown gear

The latest most accurate models

2016

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Transparent functional model in 3:1 scale


The front side

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On the front side, there were two concentric circularscales. The outer scale had 365 subdivisions and thenames of the 12 Egyptian months in Greek. The innerscale had 360 subdivisions and the names of the 12zodiac constellations. The operator, by turning the shaftto which the moon’s pointer is linked, moved the gears,which in turn rotated two pointers on the front sidethat indicated the position of the Sun and the Moon.Beneath the outer scale, which was removable, therewere 365 holes. Every four years the operator coulddetach the scales and shift them by one hole, thustaking into accountleap years. A rotatingsphere, linked by acrown gear to theMoon’s pointer,displayed the phasesof the Moon.

After 7 years of research, the members of theAntikythera Mechanism Research Team of Thessaloniki,headed by A. Basiakoulis and Dr. M. Efstathiou, designednew models of the Mechanism. The new models werebased on the second model of Aristotle’s University, butcertain mechanical parts had been improved and manyletters had been added to the inscriptions. These areconsidered the most accurate models of the Mechanismever built because they duplicate the original Mechanismbetter than previous models. In addition, the teamdesigned a model three times larger than the model withtransparent plates and lighting for exhibition purposes.

Accurate functional model in real scale

12Athens, National Archaeological Museum The American Society of Mechanical Engineers

The indicators and the inscriptions

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The Antikythera Mechanism was an analogcomputer used to calculate the position of theSun and the Moon in the sky, determine thephases of the Moon, predict the eclipses of theSun and the Moon, and indicate the celebrationdates of the ancient Panhellenic games (e.g.,the Olympic games). It had seven pointers whichdisplayed the results on correspondingmathematical scales. Two of the indicator dialsare on the front side of the Mechanism, and fiveare on the back side. The phases of the Moonwere indicated by a rotating sphere, linked witha crown gear to the Moon’s pointer. All thesefunctions were incorporated in a portable,compact machine… Was it really just acomputer, or the laptop of ancient times?
