Universe Sandbox

Universe Sandbox is a physics-based space simulator where you create, destroy and interact with celestial bodies. It combines real-time gravity, climate, collisions and material interactions to model the universe and show how planetary changes can affect a world.

Create and collide

Build a system by starting with a star and adding planets, moons, rings, comets or even a black hole. You can also collide planets and stars, leaving molten craters, or trigger a supernova by colliding two stars, increasing their mass or making them explode.

Simulate planets

The game models gravity with an N-body simulation using Newtonian mechanics, which you can run at almost any speed. You can build and terraform planets with 12 materials, including water, oxygen and carbon dioxide, and shape their oceans and mountains. Watch sea ice grow and recede as seasons change with a planet’s tilt, or move a planet closer to a star and see its surface heat up and its oceans boil away. You can also spin planets apart with centrifugal force.

Explore space

Explore historical events by riding aboard spacecraft including Juno and New Horizons, or view a total solar eclipse. The simulator also features procedurally generated planets, stars and galaxies, stellar flares and volatile trails, pulsars, light-warping black holes and space lasers.

Share simulations

You can share and explore simulations on Steam Workshop.