The prime purpose of Gravitorium is to let you play with ideas about gravity and gravitational systems. While it's not intended to be a highly accurate solar system simulator, at low speeds its accuracy is really pretty good. And, best of all, it lets you play universe maker. Throw in a few extra planets, add a black hole, set a comet plunging towards the Earth! Or create an entirely new solar system from scratch.

• MaterialWorlds Simulations 1.5
  Live interactive physics simulations let you explore the Solar System (orbits, seasons, gravity, tides, satellites and comets), play snooker (on a full size table) and experiment...

• Orbit Xplorer 2.0
  Educational orbit and gravitation simulator for high school, college and beginning university physics and astronomy

• Gravit 0.4.2
  Gravit is a gravity simulator which runs under Linux, Windows and Mac OS X. It's released under the GNU General Public License which makes it free. It uses Newtonian physics using the Barnes-Hut N-body algorithm. Although the main goal of Gravit is...

• AstroGrav (Mac) 1.3.1
  AstroGrav is a software program that allows you to study how astronomical objects move and interact under the force of gravity

• AstroGrav (Windows) 1.3.1
  AstroGrav is a software program that allows you to study how astronomical objects move and interact under the force of gravity. It features superb interactive 3D graphics which allow you to move around within an astronomical system that you are viewing, while watching how it evolves with the passage of time. A wide variety of sample files are...