The solar system is the name given to the planetary system of which the Earth is a part. It comprises planets, moons, comets, meteors and asteroids which are all held together by the gravitational pull of a star, named either the Sun or Sol. The solar system is believed to have formed from one nebula, the solar nebula . As gravity forced the nebula to condense it became more dense and pressure inside it increased, resulting in the creation of a proto-star, which began heating up to form the sun we see today. The proto-star would have been surrounded by interstellar dust and gases which began clumping together as a result of gravity. This process continued until, about 4.6 billion years ago , the clumps of rock and gas became much larger, and eventually gravity forced these irregular-shaped objects into the globular-shaped planets we see today. Many of the rocks did not become large enough to form planets and either remain today as asteroid...