Ok, I think I understand at last. Gravity explains why the planets move and objects fall to earth. Newton said they attracted each other and of course that would cause movement. Einstein said it warped space time so I conclude that causes planets to move. Warped space time is then a force that can move planets. Would that be correct?. In that context my question of why would be unneccessary and maybe ignorant of understanding gravity. Glad I asked it though. And jjw thanks for your patience and persistence, and others also. Maybe when it's all straightened out someone could move it back to the science discussion section.