I love this question!(mainly because it is about astronomy lol)
Our solar system formed from a cloud of gas and dust, called a nebula. there are many satellites orbiting our Sun, but there are eight considered to be the main planetesimals that make up our solar system. A protoplanet is a hypothetical eddy in a whirling cloud of gas and dust that later becomes a planet. The asteroids Ceres, Pallas, and Vesta are believed to be protoplanets. Gravity keeps objects like moons and asteroids close to planets. This is called a gravitational pull.
