The Titius-Bode Law approximates the distance from the Sun to the traditional planets. The Titius-Bode Law was formulated around 1770. There is no known scientific reason why the orbits of the primary planets seem to follow this relation. The law can be expressed as where is an integer representing the planet in question (0 for Venus, 1 for Earth, etc.). It is curious that Mercury needs the value , the asteroid Ceres needs , and the planet Neptune is skipped. At the time of discovery, Uranus and the more distant planets were not yet discovered.