Orrery

Orrery — a schematic top-down circular-orbit model of Mercury through Mars. Semimajor axes and sidereal periods set the relative radii and periods, so T²/a³ is nearly common across the listed planets. The position at t=0 is a chosen diagram reference, not an ephemeris or a real current planetary position. Time speed only changes animation playback. Eccentricity, inclination, perturbations, scale-correct planet sizes and light time are omitted.