Suggestion

[dreaddraco2]

I have a suggestion, seeing as you can go back in time, and also you can set gravity to repel, can you make both of these more accurate? E.g. since the moon is constantly spiralling outwards, if you go back in time it should spiral inwards and then collide with the Earth.

[atomic7732]

The outwrd only has to do with (i think) the speed and inertia of the Moon and how it is closer to the edge of the Hill Spehere.

[Dan Dixon]

In Universe Sandbox you can reverse velocities, which creates the appearance of reversing time, but it's not actually playing time backwards.

While it's true that the moon is slowly moving away from the earth (at like a centimeter or two a year, I think), I suspect that Universe Sandbox simply isn't capable of the accuracy or the speed necessary to simulate this very small change.

Something on the list (of new features to add) is drag. This would allow you to simulate the moon spiraling into the earth.