Bode, Johann Elert

[boh duh] (1747–1826) German astronomer: publicized numerological relationship between planetary distances.

Although Bode was director of the Berlin Observatory for almost 40 years and constructed a notable star atlas, his fame rests, strangely enough, on his popularization of a relationship discovered by someone else. In 1772 J D Titius (1729–96) pointed out that the members of the simple series 0,3,6,12,24,48,96, when added to 4 and divided by 10, give the mean radii of the planetary orbits in astronomical units, surprisingly accurately (even though only six planets were known at the time). (An astronomical unit (AU) is the mean distance of Earth from the Sun.) Through Bode’s publicizing of the relationship it became named after him. It played a part in the discovery of Uranus, the asteroid belt (the fifth ‘planet’), and Neptune (although its results are hopelessly inaccurate for Neptune and Pluto). It has never been proved whether Bode’s Law has any real meaning, or is merely coincidental; if the latter, it is a remarkable coincidence. In the 1990s Mazeh and Goldman at Tel Aviv noted that three planets, deduced to exist in orbits around the pulsar PSR B1257+12, have distances from it also conforming to Bode’s Law, which suggests that it may apply to all comparable planetary systems.