Answer;
The solar nebula theory
Explanation;
nebular theory
The solar nebular theory also the nebular theory is the theory about the origin of the solar system that suggests our Sun and planets formed from a nebula, a cloud of dust and gas
According to the theory the planets and sun in the solar system formed or originated from the solar nebula. Based on the theory an interstellar cloud of dust and gas moved round and thus flattening into a disk, together with the sun forming in the center and the planets in orbiting around the sun.