What an Ancient Greek Computer Tells us About the Transmission of Scientific Knowledge

In the present age, science and technology have advanced at a rapid pace. There are numerous reasons for this – population expansion, improved communication, education and effective systematisation. We assume that this is a natural progression of civilisation. However every once in a while something comes along which turns everything on its head and makes us question our assumptions. That something in this case is an ancient Greek computer known as the Antikythera mechanism.

The Antikythera Mechanism

In 1900 a group of sponge divers were stranded by a storm on the Greek island of Antikythera. They chose to search for sponges while the storm cleared. During one such dive they discovered the remains of a ship. They initially recovered a number of artifacts from the ship and later others undertook recovery work. Sadly many lives were lost during the recovery of these items.  While many items of historical significance were recovered, none were more startling than the item which later became known as the Antikythera mechanism. The device is dated to approximately 100 BC.

A superficial glance at the picture above reveals two gear-like mechanisms amongst the surrounding bronze, corroded after two thousand years in the sea of Crete.

So What Does It Do?

The obvious question to ask at this point is what is the function of the Antikythera Mechanism if anything? Here’s where the story starts to get really interesting. In 1950, historian Professor Price together with a nuclear physicist Professor Karakalos investigated the device using imaging technology and formulated a hypothesis. They believed the device was a computer that was able to calculate calendar dates and that it used a differential gear mechanism to achieve this (interestingly Professor Price was also known for Price’s law – a variation on the Pareto Principle – he suggested that 75% of the scientific literature was produced by 25% of the scientists).  A series of other investigators have applied ever more sophisticated imaging methods to the device and proposed ever more intricate interpretations of the device’s function. What became clear with these investigations was that the device had a large number of gears some of which were very small. Another team disputed the use of a differential gear mechanism. However so sophisticated is the device that several teams from across the world are continuing to work on a correct interpretation. More than 100 years after the discovery of the device, it is thought to perform several functions. The device is thought to calculate the position of the sun, moon and planets according to the Egyptian Sothic cycle and makes adjustments and eclipse predictions according to the Metonic and Saros cycles. This latter cycle is a product of the Babylonian culture. The device also displays the dates of the Olympics. The writing on the device is in Greek and also includes the first recorded reference to Spain as Hispania rather than Iberia.

Reconstruction Using Lego Bricks

In 2010 the device was reconstructed with lego bricks on the assumption that the device does indeed use a differential gear mechanism. The findings were published in Nature and feature on their YouTube channel. The video demonstrates the mechanism being used to predict a solar eclipse in 2024.

Who Created the Device?

The designer and builders of the device are unknown although candidates for the designer include Hipparchus, Archimedes and Posidonius. These polymaths were directly or indirectly influenced by other cultures including those of Egypt and Babylon which would be consistent with the influence from those cultures seen in the device.

Lost in Translation

If this device and others like it existed then why wasn’t there a gradual process of refinement over the last 2100 years? It is commonly assumed that civilisation advances through gradual improvements in all aspects of that civilisation whether this means science, technology, art, law and so on unless such a civilisation is in decline. However in this case, the discovery comes as a great surprise some 2000 years later and reveals technology that was only just reinvented in Western Civilisation a few hundred years earlier. Already by 100 BC a device of this nature is appropriated by the Romans according to Cicero. In his writing at that time the Roman possessors of this Greek technology are impressed by the device but do not appear to understand how it works. For this to happen then perhaps the only solution is to understand the theory behind the device.  That means going back to the work of the great Greek polymaths thought to have designed the device.

So the next question is what happened to the works of the Greek polymaths? Copies of these works would have been stored in the Library of Alexandria which was established by Ptolemy, a general in the army of Alexander III of Macedon. The reputation of the Library of Alexandria has lasted through the ages. However the library was partially and completely destroyed at various points in history. In a widely cited story, on the first occasion it is said that Julius Caesar accidentally set fire to the library while burning his own ships during a war against Ptolemy VIII. Work on mechanical devices does however resurface. In Baghdad in 850, a book titled Kitab al-Hiyal or the ‘Book of Ingenious Devices‘ was published and described approximately 100 mechanical devices. This book was widely disseminated and influential. Elsewhere a geared calendar device was identified from the 5-6th century AD. Although much ancient Greek scientific and mathematical theory was included in Western civilisation up until that time, it was during the Renaissance that other Hellenistic works were translated into Latin where they became more accessible.

Using the Antikythera Mechanism to Reinterpret History

If the technology behind the Antikythera Mechanism had been widely and understood, replicated and refined then perhaps history would have looked a little different. Here are a few events that are interesting to interpret in view of this device.

Kepler’s Laws of Motion

It is postulated that the gears in the device modify the course of the moon so that it approximates Kepler’s second law of motion which says that if a planet orbits the sun, then a line joining that planet to the sun will sweep out an equivalent area in an specified time period. Kepler’s laws were revolutionary at the time and later enabled Isaac Newton to formulate his theory of universal gravitation. While it is interesting to ask the question of how these two events might have been influenced by a widely disseminated Antikythera device it should also be noted that the device operates using a geocentric model. This means that the earth is considered to be the centre around which the sun and planets rotate rather than our contemporary understanding. Nevertheless it is interesting to think of how any change in these discoveries would have influenced the course of history given the various applications that have been derived.

Differential Gears and the Industrial Revolution

Richard Roberts was an engineer who in 1832 patented a differential gear mechanism for use in road locomotives which are the precursors of cars. He was an important player in Britain’s Industrial Revolution. The use of differential gears in the Antikythera mechanism has been contested although it is assumed in the video demonstration above. It should be noted that the Chinese South Pointing Chariot is described as having a differential gear mechanism and precedes the Antikythera mechanism by 1000 2500 years although there is no evidence of the original  device itself.

Charles Babbage and the Programmable Computer

The Antikythera Mechanism is an analog computer. That much is clear. Charles Babbage’s concept of a programmable computer was a revolutionary breakthrough although his design wouldn’t be implemented for another few centuries. The first program for his computer was written by Ada Lovelace, daughter of Lord Byron. The question is whether the Greek polymaths had got there first with their device. If the Antikythera mechanism had become widespread perhaps the digital computer would have arrived earlier  would be contingent on developments in electronics.

The Astrolabe and the Americas

An astrolabe is a device for predicting the movement of the sun, moon, planets and stars. Astronomer Abraham Zacuto refined a metal astrolobe and detailed many of his findings in 1496 in a book titled Ha-jibbur Ha-gadol. Portuguese sailors used his device while navigating to South America. While there are subtle differences in the Marine Astrolabe, widespread knowledge of the above device at the time of its invention would have no doubt accelerated the development of the Marine Astrolabe although the Astrolabe has numerous other functions.

Lessons From History?

The lesson to learn from this device are not restricted to physics and engineering but are relevant to other branches of science including medicine.

1. Integrate information from across civilisations. This designers of this device included Hellenistic, Egyptian and Babylonian knowledge in their device. 2000 years later despite advances in our civilisation, this device is still yielding secrets even a century after discovery and intensive study by specialised groups. However there are barriers to integration of knowledge from different civilisations. In contemporary society the modern analogy is with the emerging scientific communities in South East Asia with a potential barrier between Western and South East Asian scientific communities. The barrier in this case is language and a solution to this problem would be the assignation of a taskforce for coordinating translation of the relevant scientific work between communities although this would require considerable resources.

2. Create a civilisation-independent repository for scientific information that can be disseminated in a culturally independent manner. The information here was ‘locked into’ civilisations by various means including language. If knowledge is important then it needs to be transmitted. Science needs a flow of information between civilisations by storing it in a manner which facilitates dissemination. As an example, mathematical notation enables mathematicians globally to understand each other even without speaking the same language.  While science is an integral part of civilisation it also needs to have its ‘own space’ in recognition of the search for ‘truth’ that is common to scientists and which is ideologically and politically independent.

3. A global scientific body should recognise when contributions to a scientific field are dependent on the works of  key figures whose understanding is unsurpassed. Without such scientists that body of science is in danger of regressing. In this case, the Hellenistic polymaths did not appear to pass their knowledge onto subsequent generations or if they did then it was not easily recognised. Such work can be distributed amongst teams in a properly coordinated program.

4. For archaeological evidence the standard of reasonable evidence that is required is often incompatible with the probability of locating this physical evidence. In this case, extant written records reference devices of this nature but it is unlikely that serious consideration would be given to these without supporting physical evidence. Only a few of these devices may have been produced and it’s fortuitous that the Antikythera mechanism was discovered. Had it not been so then a certain truth about our history would have been rejected. This implies that the burden of proof should be in refutation of multiple and reliable written historical sources.

5. Important technology should be mass produced and disseminated within culture to minimise the risk of extinction of this technology and associated knowledge.  In this case the relevant science and technology for this device appears to have been restricted to a small population that was vulnerable to the risk of not being able to effectively transmit this information. It is possible to argue that this difficulty has held back science and technology by as much as 1000 years. The important conclusion here is that the rapid dissemination of key technology and science is essential to avoid loss. This applies especially to digital information where both organisational and physical distribution of data is necessary to reduce the probability of data extinction.

6. The problems associated with knowledge loss may be coming more widespread. Given the large increase in the global population together with the marked increase in education standards and an increase in intelligence at the population level (the Flynn effect) as well as systematisation countries now have have at their disposal multiple institutions having resources similar to or even greater than those at the disposal of the Greek polymaths. These institutions are integrated into society. Nevertheless the closure of departments or a change of research direction of a department carries with it the risk of loss of knowledge of a similar magnitude to that characterised by the Antikythera mechanism. While such loss is not evident in the present, the gradual improvement in knowledge had this line of investigation been pursued would compound as time progresses. To draw an analogy – if the Greek polymaths operated as todays researchers in institutes did then it would be as though the ‘research department’  developing the Antikythera mechanism was closed down due to a lack of funding. The implication is that research projects should include knowledge transfer before successful closure.


The picture of the Antikythera mechanism is distributed under a Creative Commons 3.0 License and was obtained from the following location – http://en.wikipedia.org/wiki/File:NAMA_Machine_d%27Anticyth%C3%A8re_1.jpg

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