the ancient greeks came up with their own model to track and predict
- the positions of the planets
- the position of the sun
- the position and phase of the moon
- solar and lunar eclipses
this machine is basically their mathematical models summarized into mechanical form
to clarify, this machine is way less impressive than what a lot of media claim it is. the greeks had hundreds of years of stargazing and records to figure out a model of the cosmos, and this is basically their whole model in a mechanism. unfortunately, at the time this thing was made, their model was pretty far off and they couldn't come up with a better one due to philosophical reasons (the earth is the center! the orbits of the planets must be some sort of perfect circles!).
anyway, this thing is somewhat impressive technically, but is really bad in terms of engineering:
we knew that the greeks had a model of the cosmos before we discovered this (i think). we also knew, from greek records, that there were people discussing about "spheres" that tracked the positions of the planets, sun and moon as they moved through the sky. the main thing this mechanism shows is that the ancient greeks possibly pioneered complex gear mechanisms, and the knowledge was then passed on and on and went through times like the islamic golden age before coming back to europe in the form of clockwork and watchmaking.