Question

If some planets have little to no gravity, such as the moon - then how come space dust doesn't just flow right off - or why comets don't just drift right off? (Even though it doesn't have an atmosphere.)

Answer 1

Comets Just kinda do their own thing- I beleive that Comets are usually in orbit Because of the sun-As for space dust- There is no wind or anything in space-its kinda like time stands still-Unless a black hole vibe checks Something-

Answer 2

There is gravity in space – lots of it. Because gravity is everywhere in space, objects in space are always falling: towards the earth, towards the sun, and towards the galactic center. There are two reasons that objects seem to be floating without gravity in space when they are really falling.

First, space is very large and relatively empty by earth standards. Because space is so large, it takes you from hours to years of falling through space until you actually hit the surface of a planet (assuming you have aimed properly so that you actually do hit), instead of the seconds it takes jumping off a bridge.

The second reason that gravity is not so obvious in space is because objects tend to orbit planets instead of hitting them.

Explanation: hope that helps :)