Boltzmann is a free sandbox game available on Android that allows you to create your own universe using real orbital mechanics. The simulation is loosely based on reality, and you can create blobs of matter and watch them grow into entire stars through nuclear fusion.

The game also allows you to blow up these stars with Nova Bombs, creating a diversity of rocks, planets, and beautiful orbits. The soundtrack is relaxing, making it perfect for people who love space and physics. Overall, Boltzmann is an exciting and engaging game that lets you unleash your creativity, while also teaching you about the wonders of the universe.