Modern science has no answer. Since matter does not possess the ability to move itself, one must assume that when the stars and planets were made, someone started them moving. Movement demands a Mover. Balance The balance that keeps the planets adjusted correctly in their relationship to the sun is truly astounding. It could, very easily, if not balanced properly.
Nobody really knows.
It is the force that causes bodies of mass to be attracted to one another. It causes a ball to fall to the earth. It keeps us from floating off into space. Centrifugal force has to do with the tendency of a revolving body to fly outward. Attach a weight to a string and swing it above your head.