Why are mars moons round?

Answer 1

Phobos and Deimos (Mar's moons) are not perfectly spherical. They are actually just captured asteroids. However, most moons and plants are round due to the following: Their is no gravity in space. So when the universe was formed, there were all these particles just floating around. All matter in space has their own gravitational field (a very small gravitational pull). When all that space dust was flying around, some of the particles got close enough to one another to stick (do to their individual gravitational pull). As more and more particles started sticking together, the gravitational pull gets stronger. As these masses were "growing" they "grew" evenly in all directions forming spherical entities.