The reason why the earth rotates:
1. Almost all celestial bodies in the solar system, including asteroids, rotate according to the right-handed rule, and the revolution of all or most celestial bodies is also the right-handed rule. The predecessor of the solar system is a dense cloud, which is driven by some force and attracts each other. This accretion process makes the density increase gradually and accelerates the accretion process.
2. At first, the particles in the primitive solar nebula were chaotic and rampaging, and gradually changed the disordered state into an ordered state. On the one hand, they accumulate centripetally and become the sun. On the other hand, the gas gradually develops into a flat state. In the process of development, potential energy turned into kinetic energy, and finally the whole thing turned.
At the beginning of turning, some turn this way and some turn that way. After gaining the upper hand in a certain direction, everyone turns to one direction, which is the right-handed rule now discovered. There may be other solar systems that are left-handed, but in our solar system, it is the right-handed rule. The energy source of the earth's rotation is that the potential energy of matter is finally converted into kinetic energy, and finally the earth revolves on the one hand and rotates on the other.