Antikythera Mechanism

[BillTre]

The Antikythera Mechanism is a complex clockwork-like gear mechanism found in a ship wreck off Greece from 100-200 BC.
People have been trying to understand it with a variety of methods for a long time.
it seems to have done detailed tracking of astrological events and other stuff.
I met the brother of one of the researchers of this at a archeology channel meeting that happened in Eugene several years ago. The brother was a film guy who made a documentary on his brother's work. I was"covering" it for the video production class I was in at the time (I had been interested in the Antikythera mechanism for a while already).
The current state of things (as I understand it) is summed up well in this video and I like the presenter (Simon Whistler).
Very nice 3-D model of the operating mechanism.

Maybe this should go in some other forum, but it has aspects of history, archeology, astronomy, math, and fine gear production so it seems general to me.

 

[jedishrfu]

There were some interesting gears in the device. In particular, one gear slipped back and forth to handle the lunar anomaly. Gears were hand-cut, introducing tiny errors into the calculation. Probably needed to reset from time to time.

It could handle:

• Calendar predictions: usually accurate to within a day over long periods.
• Lunar position: fairly good, within a degree or two.
• Eclipse prediction: reliable for predicting when eclipses could occur
• Planetary motion: not so precise

One of its key cycles was the Metonic cycle:

• 19 solar years≈235 lunar months

That relation is extremely good and was used to synchronize lunar and solar calendars. It also encoded the Saros cycle for eclipses:

• 223 synodic months≈18 years 11 days

Using that cycle, the machine could predict when eclipses were likely to recur.

 

[jedishrfu]

I couldn't resist:

A snapshot of Kirk and Spock on a planet wearing togas, with Spock checking the device for the next lunar/solar eclipse.

 

[jedishrfu]

and these videos showing the gears in motion:

 

[jedishrfu]

Will wonders never cease? Someone built a LEGO version (if only the Greeks had invented LEGO first):