Universe Sandbox

I haven't tried it out yet, but this galactic physics simulator looks pretty cool! According to the site, you can:

Smash moons into planets, create new stars, and build new worlds from spinning discs of debris. Explore our solar system in 3D or destroy everything you've created with a super massive black hole.

Tinker with your creation or sit back and watch the effects of gravity unfold. It's fun, accessible, and easy to use.

I feel so... GODLY! Bwahahaha!