Gravity Playground

Gravity Playground

Give worlds
a little push.

Set a world in motion. See what happens when everything pulls on everything else.

Your universe

Start with Gravity 1.00×

Try zero gravity: moving worlds travel in straight lines.

Trails Grid

Pauses time and advances one small step.

Launch a body

New body mass

In Launch mode, drag across the scene. Your body starts where you press and flies in the arrow’s direction. A longer arrow means more speed.

Launch with numbers

Choose a scene, or add a world of your own.

A flat universe, shown in 3D. Bodies merge on contact. Sizes, mass and time use illustrative units.

Universe readings

A small solar system0.00 s

Bodies: 5
Total mass: 214
Mergers: 0

An orbit is a fall that keeps missing. Add a body and watch it bend the paths around it.

body > main { display: none; }.simulation-fallback { max-width: 720px; margin: auto; padding: 24px; line-height: 1.6; }.simulation-fallback img { width: 100%; height: auto; }← Explore all worlds

Gravity Playground

Build a little universe. Launch bodies, change gravity, and watch worlds orbit, merge or fly apart.

Colored worlds and bright curved trails around a golden star, over a subtle grid against dark space.

Enable JavaScript in a browser with WebGL 2 to run this interactive simulation.

Gravity is a pull between things with mass. Here, every world pulls on every other world.

A moving world can keep falling around another one. This is an orbit. Its path depends on how fast it moves and how strongly gravity pulls.
More mass means a stronger pull. The big worlds move too: nothing is pinned in place.
When worlds touch here, they join into one. Their masses add together, and their motions combine. Real collisions can be much more complicated.
Trails show where worlds have been. Everything moves on one flat plane, with made-up units so you can experiment.

Try this: Choose Launch bodies and drag across the scene. Then set Gravity to zero and watch the paths straighten. Restart to try again.