BBC documentary on the Antikythera Mechanism

[lethargic_man]

Très cool.

Comments

[curious_reader]

Are you talking about "The Two-Thousand-Year-Old Computer"? I found that very interesting. I still don't understand if the Greeks were actually able to figure out the lunar years and planet years exactly with that mechanism. The scientist seemed to have troubles with it, too, with that small machine they found.

[lethargic_man]

They didn't figure out the astronomical calculations with the Antikythera mechanism; they figured those out by looking at the night sky and making lots of calculations. The Antikythera mechanism was to enable them to extrapolate the movement of the heavenly bodies easily an arbitrary amount of time into the future, rather than doing it manually with a vast number of calculations (which would have been without the benefit of lots of things which make maths more easy for us, such as the number zero, a tens-based numeric representation system (what's LXVIII × DCIV?) and algebra).

[curious_reader]

Ok, I got it. At least I know what you were talking about.
68x604=41072
I had to cheat. I forgot what L and D stands for. I looked it up on the internet. I learnt those in school.

What are you calculating here?

[lethargic_man]

You're missing the point, which is that when you're working out 68 × 604 you can line the numbers up and do long multiplication like you were taught in school. With LXVIII × DCIV that's impossible; the only way to do it is to use an abacus.

[curious_reader]

I use a calculator since they introduced them in school. It goes much faster nowadays.

[lethargic_man]

That's the point I'm trying to make—it's easier to use a calculating machine, whether it's made two thousand years ago from gears, or twenty years ago from printed circuit boards.

[curious_reader]

That was not my question. What was it what they calculated? I understood they calculated the lunar and solar years. But the scientist argue that it is difficult because the moon moves sometimes faster and sometimes slower.

[lethargic_man]

Firstly, will you please respect the threading rather than just hitting "Reply" at the bottom of the page.

Secondly, the Antikythera mechanism calculated the position of the principle moving objects in the sky (moon and planets) in terms of solar years. The moon's differing motion is predictable; when it's closer in it moves faster. That was what the pin-and-slot arrangement was for, to turn a constant motion of one gear into a sometimes faster, sometimes slower motion in another.

[curious_reader]

Sorry, I was hitting the reply button because I was not asking again about calculation but about the actual purpose of the small machine. I got it now. That is why they had this small needle thing inside to slow down the gears.