Bode

Collier's New Encyclopedia (1921)

JOHANN ELERT, a German astronomer, born in Hamburg, Jan. 19, 1747; became astronomer of the academy in Berlin, in 1772, and, in 1786, director of the observatory there. He published numerous astronomical works, including "Sternkunde" (3d ed., 1808), and "Uranographia" (2d (2d ed., 1818), and founded the "Astronomische Jahrbücher." He died Nov. 23, 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 of 2, putting the 3 under the second 4; and by addition we have the series 4, 7, 10, etc., which gives nearly the relative distances of the planets from the sun. 4 4 4 4 4 4 4 4 4 96 192 384 6 12 24 48 3 7 10 16 28 52 100 196 388 4 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 follows, making 10 the distance of the earth: Asteroids Neptune Mercury Uranus Jupiter Saturn Venus Earth Mars 3.9 7.2 10 15.2 37.4 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 has proved the correctness of this prediction.