Jason Allemann of JK Brickworks used LEGO to create a fairly accurate orrery that depicts the relative rotations of the orbits of the Earth, Moon, and Sun. The model makes an impressive approximation of the time it takes for these three bodies to move in relation to one another.
Allemann has also posted building instructions for anyone looking to replicate the orrery.
A LEGO Orrery featuring the Earth, Moon and Sun. I tried to focus on making the rotation and movements as accurate as possible without making it too complex. It can be powered manually using the crank, or with a Power Functions M-Motor.
The relative sizes and distances between the objects is obviously not to scale, a concession often taken with these models. It’s also missing the tilt of the Earth and inclination of the Moon’s orbit. Perhaps some things that could be added in the future.