Bode's law

The empirical rule relating the approximate distances of the solar system planets from the Sun. The original formulation was: a = (n + 4) / 10, where a is the mean distance of a planet from the Sun in astronomical units and n = 0, 3, 6, 12, 24, 48, 96, 192 (doubling for each successive planet). The planets were seen to fit this sequence quite well, provided the asteroids between Mars and Jupiter are counted as one planet, as did Uranus discovered in 1781. However, Neptune and the ex-planet Pluto do not conform to the rule. The question of whether there is any physical significance to the 'law,' i.e. some dynamical reason that will explain planetary orbit spacing has led to much discussion during the past two centuries. Today, many astronomers are very skeptical and consider this 'law' to be numerical coincidence.