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.