Bode's law

/boh"deuhz/, Astron.

a numerical scheme that gives the approximate distance from the sun of the seven inner planets but fails for Neptune and Pluto. Also called Titius-Bode law.

[1825-35; after Johann E. Bode (1747-1826), German astronomer, though prob. first formulated by Johann D. Titius (Tietz) (1729-96)]

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Rule giving the approximate distances of planets from the Sun.

First announced in 1766 by the German Johann Daniel Titius (b. 1729

d. 1796), it was popularized, from 1772, by his countryman Johann Elert Bode (b. 1747

d. 1826). It may be given as follows: To each number in the sequence 0, 3, 6, 12, 24, and so on, add 4 and divide the result by 10. The answers closely approximate the distances from the Sun, in astronomical units, of the first seven planets. Bode's law also suggested that a planet should be found between Mars and Jupiter, where the asteroid belt was later discovered. Once thought to have some significance regarding the formation of the solar system, it is now regarded as a numerological curiosity.

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▪ astronomy

also called  Titius-Bode law 

      empirical rule giving the approximate distances of planets from the Sun. It was first announced in 1766 by the German astronomer Johann Daniel Titius (Titius, Johann Daniel) but was popularized only from 1772 by his countryman Johann Elert Bode (Bode, Johann Elert). Once suspected to have some significance regarding the formation of the solar system, Bode's law is now generally regarded as a numerological curiosity with no known justification.

      One way to state Bode's law begins with the sequence 0, 3, 6, 12, 24,…, in which each number after 3 is twice the previous one. To each number is added 4, and each result is divided by 10. Of the first seven answers—0.4, 0.7, 1.0, 1.6, 2.8, 5.2, 10.0—six of them (2.8 being the exception) closely approximate the distances from the Sun, expressed in astronomical units (astronomical unit) (AU; the mean Sun-Earth distance), of the six planets known when Titius devised the rule: Mercury, Venus, Earth, Mars, Jupiter, and Saturn. At about 2.8 AU from the Sun, between Mars and Jupiter, the asteroids were later discovered, beginning with Ceres in 1801. The rule also was found to hold for the seventh planet, Uranus (discovered 1781), which lies at about 19 AU, but it failed to predict accurately the distance of the eighth planet, Neptune (1846), and that of Pluto, which was regarded as the ninth planet when it was discovered (1930). For a discussion of the roles that Bode's law played in early asteroid discoveries and the search for planets in the outer solar system, see the articles asteroid and Neptune.

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