Page:The Music of the Spheres.djvu/243

 consists of 84 of our years, each hemisphere has 42 years of darkness and 42 years of light.

The four inner planets are quite solid in comparison to the four outer ones, which are largely gaseous. Mercury is the most solid planet of all, being more like metal than the earth; neither Jupiter nor Saturn have stable surface crusts while Saturn is so light that it would float on water.

Following are the diameters of the planets starting from Mercury, nearest to the sun, to Neptune, the farthest away.

The planets that are relatively near the sun have few or no satellites, Mercury and Venus having none, Earth one, Mars two; those farther distant have a goodly number, Uranus possessing four, Jupiter nine and Saturn ten.