Planets

Aiton's Encyclopedia (1910)

heavenly bodies revolving about the sun. The ancients noticed that several stars changed position in the heavens and gave them the name of planets or wanderers. It was noted also that they shone with a steady, not a twinkling light. In addition to the sun and moon, five wanderers were recognized and were given the names of divinities,--Mercury, Venus, Mars, Jupiter, and Saturn. The earth was not counted because it was considered the stationary center of the universe. Uranus and Neptune have been discovered later. Arranged in order of distance from the sun, the planets fall into place in accordance with Bode's Law, expressed as follows: Write a series of 4s. Add 3 to the second 4. Add twice 3 or 6 to the third 4. Add twice 6 or 12 to the fourth 4. The series may be extended indefinitely by doubling the added number each time. The working of the law may be shown as follows: 1st. 2nd. 3rd. 4th. 5th. 6th. 7th. 8th. 9th. 4 4 4 4 4 4 4 4 4 3 6 12 24 48 96 192 384 -------------------- 4 7 10 16 28 52 100 196 388 In searching for the planet that might be expected to occupy fifth place, astronomers have found large numbers of small bodies with planetary orbits, fragments apparently of a lost planet, to which the name of asteroids has been given. Using the distance of the earth from the sun as a measure, the names of the planets, comparative distances and Bode numbers may be seen in the following table of planetary bodies: Name. Distance. No. Mercury 0.387 4 Venus 0.723 7 Earth 1.000 10 Mars 1.523 16 Asteroids 28 Jupiter 5.202 52 Saturn 9.539 100 Uranus 19.183 196 Neptune 30.054 388 Choose any well leveled field. On it place a globe two feet in diameter. This will represent the sun. Mercury will be represented by a grain of mustard seed on the circumference of a circle 164 feet in diameter for its orbit; Venus, a pea, on a circle of 284 feet in diameter; the Earth, also a pea, on a circle of 430; Mars, a rather large pin's head, on a circle of 654 feet; the asteroids, grains of sand, on orbits having a diameter of 1,000 to 1,200 feet; Jupiter, a moderate-sized orange, on a circle nearly half a mile across; Saturn, a small orange, on a circle of four-fifths of a mile; Uranus, a full sized cherry or small plum, upon a circumference of a circle more than a mile in diameter; and finally, Neptune, a good-sized plum, on a circle about two and a half miles in diameter.--Sir John Herschel.