The dominant scientific model is that the Earth and all theplanets (and the Sun) coalesced from a molecular cloud, also knownas a nebula.Supernovae are the only known natural events capable ofproducing elements heavier than Iron, and since heavy elementsexist on Earth (and in the Sun), the debris field must have comefrom a supernova.Clouds of gas and debris which exist in space have centers ofgravity which cause the debris field to collapse toward a centralpoint. This process is known as planetary accretion. As the gravitypulls material in and bits of mass collapse, angular momentum isconserved and primary rotation(s) begin. The solar system as wellas the planets all rotate due to conservation of angular momentumaround various gravitational centers.Of course there are other "theories," or beliefs regarding thecreation of the Earth, but these are not based on scientificevidence. Many people believe the Earth was createdinstantaneously, out of nothing, by a deity.