Universe Sandbox is a realistic physics-based space simulator that allows you to create, destroy, and interact on an unimaginable scale.

It merges real-time gravity, climate, collision, and material interactions to reveal the beauty of our universe and the fragility of our planet.

Simulate Gravity

N-body simulation at almost any speed using Newtonian mechanics. Real science, real physics, no supercomputer required.

Collide Planets & Stars

Epic, mind blowing collisions of massive planetary bodies that leave behind molten craters.

Create Your Own Systems

Start with a star, then add a planet. Spruce it up with moons, rings, comets, or even a black hole.

Model Planetary Climate

Watch sea ice grow and recede with the seasons because of a planet’s tilt - change the tilt and change the seasons. Or move planets close to a star and see the oceans boil away as the surface heats up.

Supernova a Star

Watch a supernova unfold by colliding two stars, cranking up their mass, or making them explode at your whim.

Explore Historical Events

Hitch a ride with spacecraft including Juno and New Horizons, or view a total solar eclipse.

And more...

• Build and terraform planets with 12 materials, including water, oxygen, & carbon dioxide


• Stellar flares & volatile trails


• Procedurally generated planets, stars, & galaxies


• Pulsars


• Light-warping black holes


• Epic space lasers


• Shape oceans & mountains on planet surfaces


• Spin planets apart with centrifugal force


• Original soundtrack by Macoubre


• Support for 20+ languages


• Share & explore simulations on Steam Workshop