By ticking the 'model' box, you can switch between the [i]heliocentric [/i]model of the cosmos, introduced by Aristarchus of Samos (c. 310 BC -- c. 230 BC), and the [i]geocentric [/i]model, based on [i]deferents [/i]and [i]epicycles[/i], introduced by Apollonius of Perga (c. 240 BC -- c. 190 BC).[br]The illustration is based on actual distances.[br]Tick the 'traces' box to view the paths left by the planets.