History · Planets
Orrery
Say it: OR-uh-ree IPA: /ˈɔrəri/ noun
Orrery: A mechanical model illustrating the arrangement and orbital motions of bodies in the solar system.
Gears and moving arms carry model planets around a model Sun. The mechanism turns an abstract orbital diagram into something you can watch move.
- Example
- Turning the handle set the orrery's planets in motion.
- Why astronomers use it
- It makes relative orbital motion easier to demonstrate and understand.
- Tiny cosmic connection
- An orrery usually cannot show planet sizes and orbital distances at one practical scale.
Observatory History Planets
Where to check it
Written for Cool Moon Facts in its own words; the sources cover the same idea in more depth.