Community-built physics experiments and study materials — run an experiment live and fork it into your own studio, or read a guide someone wrote.
The real Earth-Moon system, in real units. One grid cell is 1000 km, one mass unit is 10^22 kg, one second is ten minutes. Nothing is tuned: Earth carries its measured 5.97 x 10^24 kg, the Moon sits 384,400 km away, and the pull is Newton's F = G M m / r squared with G converted into these units. The 27.3-day orbit that comes out is what those numbers produce. Only the globes are drawn larger than life so you can see them; their masses are untouched.
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.
