Universe Sandbox turns the cosmos into a space for experimentation, using real-time gravity, climate, collisions, and material interactions. Rather than centering on a conventional campaign, it lets players create, alter, and observe astronomical systems, connecting the spectacle of space with the fragility of planetary environments.
Build a system around a star, then add planets, moons, rings, comets, or a black hole. Newtonian gravity drives an N-body simulation that can run at adjustable speeds, while climate models show how a planet’s tilt affects seasonal sea ice or how proximity to a star can heat oceans until they boil away. Players can also terraform worlds with materials such as water, oxygen, and carbon dioxide, or collide planets and stars to observe the aftermath.
The design ranges from constructing custom systems to staging dramatic cosmic events, including supernovae, and exploring historical scenes such as a total solar eclipse or spacecraft journeys. Steam Workshop support lets players share and explore simulations.
