History of Solar System formation and evolution hypotheses occur in the interstellar material from which stars are born) formed the Sun and protoplanets, the latter splitting to form planets. The 2 portions can not remain gravitationally bound to each other, are at a mass ratio of at least 8 to 1, and for inner planets they go into independent orbits while for outer planets one of the portions exits the Solar System. The inner protoplanets were Venus-Mercury and Earth-Mars. The moons of the greater planets were formed from "droplets" in the neck connecting the 2 portions of the dividing protoplanet and these droplets could account for some of
Geology of Venus Geology of Venus Venus is a planet with striking geology. Of all the other planets in the Solar System, it is the one nearest to Earth and most like it in terms of mass, but has no magnetic field or recognizable plate tectonic system. Much of the ground surface is exposed volcanic bedrock, some with thin and patchy layers of soil covering, in marked contrast with Earth, the Moon, and Mars. Some impact craters are present, but Venus is similar to Earth in that there are much fewer craters than on the other rocky planets that are largely covered by