Step 1

The first part of this theory says that the solar system started out as only dust and gasses. This is called a solar nebula. The solar nebula started spinning because gravity collapsed on it. This lead to the creation of the sun. Leftover materials clumped together while solar wind blew the smaller particles away. This meant that the only things left to form Earth were huge rocks and heavy metals.

This is a picture
of a solar nebula.