Orbital Motion

How this simulation works

Use the Orbit Radius slider to set the distance between the planet and the star (in metres), and the Star Mass slider to scale the central gravity (in GM×10³ units). Press Start to launch the planet at the orbital speed required for a stable circular orbit, Pause to freeze it mid-orbit, and Reset to restart. Larger radii produce slower, longer orbits; heavier stars pull the planet around faster. The force and velocity vectors trace the balance between gravity and inertia that keeps the planet in orbit.