Planet earth with its diameter of 7, 926 miles (measured through the poles), rests basically on nothing, yet the earth races along its elliptical orbit around the sun in exactly three‑hundred sixty‑five and a-quarter days. Isaac Newton defined this force in his "law of gravitation" when he said that the gravitational force is directly proportional to the product of two masses (e.g., the Earth and the Moon) and inversely proportional to the distance between them squared. The entire universe is held in harmony by an intricate system of balances and tensions.