Universe Sandbox

You’ve got to try this out

Universe Sandbox lets you “Smash planets together, introduce rogue stars, and build new worlds from spinning discs of debris. Fire a moon into a planet or destroy everything you’ve created with a super massive black hole.”.

This is a fantastic and fun way to learn about physics, and smash a few celestial bodies up along the way. I’ve never seen anything quite like this before, so hats off to the developer for coming up with something pretty unique.

Interestingly, there’s no fixed price for the application. Simply pay the author what you think it’s worth. Can’t ask fairer than that!