A Lump of Bronze

Nell: In the spring of 1901, sponge divers working off the Greek island of Antikythera brought up something nobody could explain.

Theo: This is the shipwreck, right? A cargo ship that went down in the first century BC, loaded with bronze statues and glassware.

Nell: That's the one. And among the treasures was a corroded lump of bronze and wood, about the size of a shoebox. The next year, an archaeologist noticed a gear wheel in it.

Theo: A gear wheel. Two thousand years old.

Nell: Today it survives as eighty-two fragments in the National Archaeological Museum in Athens, with at least thirty bronze gears.

A Computer for the Sky

Theo: So what did it actually do?

Nell: You turned a handle, and the dials showed where the sun and the moon were, the phase of the moon, and when the next eclipses would come.

Theo: And the moon even sped up and slowed down, the way it really does in the sky. That came from a pin riding in a slot between two gears.

Nell: X-ray scans in 2005 revealed thousands of tiny letters engraved on it, a user's guide of sorts. There's even a dial for the athletic games, the Olympics among them.

Theo: And nothing that intricate turns up again for more than a thousand years.

Nell: Which is why it's often called the first analog computer.
