Play Them.

Gravity Simulator

Fling planets and change physics in this gravity sandbox. Play online for free, or get the full version for: fullscreen mode, faster calculations, more planet images, General Relativity, mod support, editable colors, and more.

Want to add 1000 planets? Go ahead.
Curious about Lagrange Points? Make em.
Hate the inverse square law? Change it.

Learn more about the full version.

Download it.

Grav. Grav. Grav. Grav. Grav. Grav.

Full Version Features

The full simulator can do more than the online version. A quick list...

  • Much more powerful, can handle more planets
  • More planet images to pick from, or import your own
  • Test out arbitrary force laws
  • Set the potential, add in a tangential force, modify quality settings
  • General Relativity (black holes, two-body orbits, etc)
  • Customizable colors and lines
  • Speed up and slow down time
  • Track planets, seeing the world from their frame
  • Displays energy (kinetic/potential) of each object
  • And more. Oh, is there more.

The Science

Gravity Simulator lets you control one of the most basic forces in the universe. Launch stars and planets, and watch as gravitational patterns unfold. Peaceful conic sections, dancing spirals, wonderful spirographs, and plenty of utter chaos will appear before your eyes.

But your powers don't stop there - you can also change the underlying physics of the simulation. Maybe, instead of a 1/r^2 force law for gravity, you'd like to see what happens if there were a 1/r^2.1 force law. Or a tan(r) force law. Or any strange force law you can come up with. You can even turn on General Relativity, and see what happens in a world where a massive object warps space. What weird and fascinating universes can you create by playing with the laws of physics?

Blog Posts:

For Teachers

If you're looking to get copies for your students, you can email me for help on bulk/educator orders (address at bottom of page).

Learn More!

I've posted a new site full on information about the simulator. How it works, the science behind it, etc. Worth a look: GSim 101.


The simulator is a work-in-progress. If you find any bugs or desperately want and features, join in the discussion in the forums, get in touch with me, and help make the simulator even better.


Grab some screenshots, or learn more about the story of the game by going to our presskit(). Or you can always email me, andy, at this website's domain.