DAY AND NIGHT
The length of Saturn’s day, or its period of rotation on its axis, is about ten hours and a quarter. Like Jupiter, it has slightly different rates of rotation in different latitudes, thus showing its lack of solidity. The rate of rotation has been determined, as in the case of Jupiter, by observation of the spots on its surface, which, while they are not exactly permanent, yet remain apparently in the same positions for months and even years at a time, and are thus sufficiently stable to measure a rotation of so short a time as ten hours.
Whirling over at this rate would cause the sun to appear to skim across the sky very swiftly as viewed from Saturn. In size, it would not seem more than three times as large as Venus at her brightest seems to us, and every minute it would cover a distance about equal to the diameter of the full moon as we see it. In an hour it would seem to move more than six times as far as the distance between the “pointers.” At the time of Saturn’s equinox the little five-hour day, followed by the equally short night, must present a lively aspect with the sun racing thus swiftly across the sky in daylight and the stars sweeping as swiftly over at night. If things remain as they now are, it will be a splendid panorama for the people there when, in the far-distant future, Saturn may have cooled and solidified sufficiently to maintain life somewhat as we know it. The earth, though, and Venus and Mars would be from Saturn only telescopic objects to eyes like ours, and Jupiter no brighter than he is to us. Thus does our brother Saturn pay the price of his remoteness from the rest of the solar family.