At the belated St Patrick’s Day dinner I attended last week there was an interesting guest: Michael Wright, a mechanical engineer, although that hardly does him justice. We have to go back some way to understand his achievement, in fact to Antikythera in the Aegean in about 80 BC where a cargo vessel carrying booty from Rhodes to Rome – for Julius Caesar – was wrecked.
It lay undiscovered on the seabed until some sponge divers found it in 1900. There were many conventional artifacts such as bronze and marble statues, jewellery, pottery, glassware and coins but in addition some encrusted bronze cogwheels. At first it was thought that these must be much more recent than the contents of the wreck and they were stored in boxes at the National Museum of Archaeology in Athens and neglected until the 1970s when it was possible to make gamma-ray images of the encrusted metal.
It emerged that these cogs meshed to make a complicated Ancient Greek analogue computer. Wiki explains what it could do.
Detailed imaging of the mechanism suggests that it had 37 gear wheels enabling it to follow the movements of the moon and the sun through the zodiac, to predict eclipses, and even to model the irregular orbit of the moon, where the moon’s velocity is higher in its perigee than in its apogee. This motion was studied in the 2nd century BC by astronomer Hipparchus of Rhodes, and it is speculated that he may have been consulted in the machine’s construction.
So far so theoretical until Michael Wright came along. He was the first person to design and build a model based on the known components that had been salvaged and adding his emulation of a potential planetarium system. He must have found it a doddle making Airfix models when he was a lad.
