Orbit Simulator app for iPhone and iPad

Orbit Simulator simulates the motion of bodies under the influence of mutual gravitational forces. Up to 200 bodies may be in play at any one time. It is intended to be both educational and entertaining.

The simulator has two modes of operation:

In “Normal” mode you start with a blank canvas, and can place bodies of different types with varying initial velocities and watch the system evolve.

In “Central sun” mode you start with a sun-sized body in the centre of the screen, and can place bodies which initially move in a circular orbit around the central sun.

The simulation speed may be adjusted within limits, and trails showing past motion may be turned on and off.