Bode, JOHANN ELERT

Bode, JOHANN ELERT, astronomer, was born at Hamburg, 19th January 1747; in 1772 he became astronomer of the academy in Berlin, and in 1786 director of the observatory there. He published numerous astronomical works, including Sternkunde (3d ed. 1808), and Uranographia (2d ed. 1818), and founded the Astronomische Jahrbücher. He died 23d November 1826. The arithmetical relation subsisting between the distances of the planets from the sun, called after him Bode's Law, may be thus stated: Write, in the first instance, a row of fours, and under these place a geometrical series beginning with 3, and increasing by the ratio 2, putting the 3 under the second 4; and by addition we have the series 4, 7, 10, &c., which gives nearly the relative distances of the planets from the sun.

Thus, if 10 be taken as the distance of the earth from the sun, 4 will give that of Mercury, 7 that of Venus, and so forth. The actual relative distances are as follow, making 10 the distance of the earth:

Mercury, Venus, Earth, Mars, Asteroids, Jupiter, Saturn, Uranus, Neptune.
3·9 7·2 10 15·2 27·4 52·9 95·4 192 300

Close as is the correspondence between the law and the actual distances, no physical reason has been given to account for it, although there is little room for doubt that such exists. Bode's law is therefore, in the present state of science, empirical. Kepler was the first to perceive the law, and Bode argued from it that a planet might be found between Mars and Jupiter, to fill up the gap that existed at the time in the series. The discovery of the Planetoids (see PLANETS) has proved the correctness of this prediction.