Build your own solar system – place bodies, set velocities, watch orbits

Integrated ScienceEarth & SpaceAges 11–12

Place up to 4 bodies with any mass, position and starting velocity, then press Play to see what kind of orbit gravity produces: a circle, a closed ellipse, an escape or a collision. The Intro screen has 2 bodies for quick experiments; the Lab screen has 5 ready-made set-ups (Sun–planet, Sun–planet–moon, binary star, figure-eight orbit, four-body chaos) and a table of each body's mass, position and velocity. Based on the "My Solar System" simulation by PhET Interactive Simulations, University of Colorado Boulder (CC BY 4.0); rewritten.

Lesson: The Solar System and the Milky Way