Community-built physics experiments and study materials — run an experiment live and fork it into your own studio, or read a guide someone wrote.
A small body on an elliptical orbit around a fixed star. The pull follows an inverse-square law, so it's fastest at closest approach and slowest out at the far end of the ellipse — the same trade Kepler's second law describes, read straight off the glow and the trail.
Real masses, real perihelion distances, real perihelion speeds, and Newton's G converted into scene units — one length unit is a million kilometres, one mass unit is 10^23 kg, one second is three hours. Nothing is tuned to make the orbits close: each planet is released at its measured perihelion with its measured speed, and the ellipse that follows is whatever the equation produces. Mercury's eccentricity, Earth's near-circle and Mars's 687-day year all fall out of it. Only the globes are big.