A short history, and an orrery you can fly
An orrery is a model of the Solar System that shows the planets moving around the Sun. Turn its handle, or let its clockwork run, and the planets go round in step with their real years: Mercury fastest, the outer planets slowest.
The first orreries of the modern kind were made in England in the early 1700s by the clockmakers George Graham and Thomas Tompion. The instrument maker John Rowley built one for Charles Boyle, 4th Earl of Orrery, and the instrument took his title.
A mechanical orrery gets the order of the planets and their relative periods right, but not their sizes or their distances. At true scale the planets would be specks too small to see, metres to kilometres apart, so every orrery squeezes the distances and swells the planets. Most draw the orbits as circles. A tellurion is the small cousin: it shows only the Sun, the Earth and the Moon, to explain day and night, the seasons and the Moon's phases.
Orrery Space is an orrery that runs in your browser. The planets move on their real, elliptical orbits, worked out from published orbital elements, for any date you choose, and you can switch between an explorer scale that makes them visible and true scale. It also goes where no brass orrery can: to every planet, moon and comet, to thousands of other planetary systems, across the Milky Way to its central black hole, and to landing sites at the Moon's south pole.