Why does the earth spin?
A very simplified is: The prevailing scientific theory that attempts to this question is a continuation of the “big bang” theory. Our solar system seems to have condensed from a cloud of gas and dust. We have seen from experimental observations of clouds and collisions that when things clump together, there is usually some sort of spin imparted to the resulting collection (in our case, Earth). Newton and others have also theorized that “a body in motion tends to stay in motion”, so without a large influence we will probably continue to spin.