Gravity Sandbox

About Gravity Sandbox

Gravity Sandbox is a browser-based space sandbox that gives you a dark grid, a handful of moving bodies, and room to test an idea. Instead of following levels, you decide where the next body goes. One click can turn a tidy orbit into a close encounter; changing mass can make the rest of the scene bend around it. Coloured trails help you see what happened after the bodies have moved on.

The useful question is not “Can I build a perfect solar system?” but “What changed when I added one object?” In Gravity Sandbox, start with the bodies already on screen. Watch their paths for a few seconds, add one more body off-centre, then compare the new trails with the old ones. If the screen becomes crowded, clear it and repeat with a different mass. Gravity Sandbox is an interactive toy, not a scientifically calibrated astronomy lesson: its values make experiments visible and fun.

Controls and first steps

Choose Add (the plus icon) in the left toolbar, then click the grid to place a body. Pan moves your view and Select lets you work with an existing body. The toolbar also has play/pause and clear. On the right, set the mass and colour for new bodies, then adjust speed and gravity. The status strip at the bottom shows the current mode and body count, so check it before clicking if nothing appears to happen.

Keyboard shortcuts from the original project: Space toggles play/pause; P selects Place; H selects Pan; S selects Selection; C clears all. Ctrl+Z and Ctrl+Y undo and redo; Delete removes a selected body. On a touch device, use the visible controls first. Touch play has not been checked on this site's version.

Three small experiments

1. One extra body: add a single body near an existing orbit. Watch whether it joins the path, passes through, or pulls its neighbour away.
2. Change the mass: clear the scene, place two bodies, then raise the mass before adding a third. Compare how the paths curve.
3. Change the clock: slow the simulation to inspect a close approach, then speed it up to see the longer pattern. Keep the layout unchanged so the comparison stays useful.

Gravity Sandbox has no win screen or fixed level order. When a result surprises you, reset and change just one setting. That makes it easier to understand which adjustment caused the new pattern. Gravity Sandbox is intended for play and exploration; do not use it to predict a real planetary orbit.

Where to go next

If you want a collision scenario with a camera around Earth, try Doomsday Simulator. For a broader set of browser experiments, browse the . For quick destruction tools instead of building a system, return to Solar Smash.

Creator and credits

Gravity Sandbox was created by Siddharth Roy and released under the MIT License. Original source and credits. This independent site hosts a local browser build; the original licence remains in the game package. The game is separate from the official Solar Smash app.

Gravity Sandbox FAQ

Why does clicking the grid sometimes move the view instead of adding a body? Check the bottom status strip. The page opens in PAN mode. Select the plus button to switch to ADD, then click the grid away from the toolbars. In the browser test, this changed the body count from 5 to 6; returning to Pan changed the mode label back to PAN without removing the added body.

How can I check that an experiment actually changed the scene? Read the body count before and after placing an object. A new trail alone can be misleading because existing bodies keep moving. Add one body at a time and keep mass and gravity unchanged while comparing the result. The automated page check repeats a real placement and requires the count to increase; a loading screen or animated background does not pass.

Do I need to restart when I choose the wrong tool? No. Switching between Add and Pan changes what the next pointer action does. It does not reset the body count. Use the visible mode label to check your selection before trying another click. These observations apply to the embedded desktop build; phone touch gestures and save-file persistence have not been verified.