A fragment from
a complex mechanism was discovered by chance near Olbia, Sardinia, and it soon
became clear that the dented gear wheel showed similarities with the mechanism
of Anticythera.
This fragment, however, was made of a brass alloy unknown otherwise at the
time.
Thanks to the
detailed writings of Cicero in the 1st century BC, we
know that Archimedes constructed a
Planetarium (Orrery). The celestial globe is mentioned by Ovid in the 1st century BC and by Claudian, a 4th-century Latin poet associated with the
court of Emperor Honorius in Mediolanum
(Milan).
When, in 212 BC,
the Romans sacked Syracuse, Consul Marcus Claudius Marcellus brought to Rome a
device that was built by the famous mathematician. It represented the motion of
the Sun, Moon, and the planets reproduced on a sphere. In short, a modern Planetarium.
It was Gaius Sulpicius Gallus, who reported the
story as he had seen the object personally and knew how to operate it. Cicero was amazed that Archimedes had been
able to generate the motion of the individual planets starting from a single
rotation. The Planetarium was placed inside a glass sphere. This corresponds to
what Archimedes wrote in a now-lost treatise On Sphere-Making detailing the construction of the Planetarium.
Livy, who died in
17 AD, wrote that before the Battle of Pydna in 168 BC, Gallus, an astronomer himself, used the Planetarium to predict a
lunar eclipse on the night before the battle. The news was shared with his Roman
legionnaires to prevent them from panicking, but the Macedonians freaked out.
A first
reconstruction based on the section of the gear wheel found near Olbia revealed that it counted 55 dents
in total. Noteworthy is the shape of the dents, which is not triangular as in the
case of the Anticythera mechanism but slightly curved as used in our modern
gear wheels. This shape proves to be more efficient and allows a higher
precision. In antiquity, these wheels were created manually and the craftsmen
had to do without the use of our modern measuring and cutting tools, which
emerged only a few centuries ago.
Marcus Claudius Marcellus,
owner of the Planetarium, was sent off to Spain to fight the Iberic Celts in
152 BC. It is reasonable to assume that Marcellus took the Planetarium with him
– a sign of his status – and that his ship was wrecked in the region of Olbia, crashing
the Planetarium.
The Planetarium has
been dated between the end of the 3rd century BC and the mid-2nd
century BC. It thus predates the Anticythera mechanism from the 1st
century BC generally ascribed to Archimedes. However, the analog computer may
well have been reproduced based on Archimedes’ description.
It must have
been one of the marvels from Hellenistic times, many of which still remain to
be discovered!
[the section found near Olbia is thoroughly discussed in this YouTube]