The human mind has used Saturn and the two known planets beyond for the last 200 years as a gymnasium. It has exercised itself in comprehending their enormous distances in order to clear those greater spaces, to where the stars are set; it has exercised its ingenuity at interpreting appearances which signify something other than they seem, in order that it may no longer be deluded by any sunrises into a belief that the heavenly dome goes round the earth. That a wandering point of light should develop into such amazing grandeurs under the telescope, is as unexpected as that every tiny seed should show peculiar markings and colors under the microscope.
There are certain things that are easy to determine, such as size, density, periodic time, velocity, etc.; but other things are exceedingly difficult to determine. It requires long sight to read when the book is held 800,000,000 miles away. Only very few, if more than two, opportunities have been found to determine the time of Saturn's rotation. On the evening of December 7th, 1870, Professor Hall observed a brilliant
Fig. 65.—View of Saturn and his Rings. white spot suddenly show itself on the body of this planet. It was as if an eruption of white hot matter burst up from the interior. It spread eastward, and remained bright till January, when it faded. No such opportunity for getting a basis on which to found a calculation of the time of the rotation of Saturn has occurred since Sir William Herschel's observations; and, very singularly, the two times deduced wonderfully coincide—that of Herschel being 10h. 16m., that of Mr. Hall being 10h. 14m.
The density of Saturn is less than that of water, and its velocity of rotation so great that centrifugal force antagonizes gravitation to such an extent that bodies weigh on it about the same as on the earth. All the fine fancies of the habitability of this vaporous world, all the calculations of the number of people that could live on the square miles of the planet and its enormous rings, are only fancy. Nothing could live there with more brains than a fish, at most. It is a world in formative processes. We cannot hear the voice of the Creator there, but we can see matter responsive to the voice, and moulded by his word.
Rings of Saturn.
The eye and mind of man have worked out a problem of marvellous difficulty in finding a true solution of the strange appearance of the rings. Galileo has the immortal honor of first having seen something peculiar about this planet. He wrote to the Duke of Tuscany, "When I view Saturn it seems tricorps. The central body seems the largest. The two others, situated, the one on the east, and the other on the west, seem to touch it. They are like two supporters, who help old Saturn on his way, and always remain at his side." Looking a few years later, the rings having turned from view, he said, "It is possible that some demon mocked me;" and he refused to look any more.
Huyghens, in March, 1655, solved the problem of the triform appearance of Saturn. He saw them as handles on the two sides. In a year they had disappeared, and the planet was as round as it seemed to Galileo in 1612. He did not, however, despair; and in October, 1656, he was rewarded by seeing them appear again. He wrote of Saturn, "It is girdled by a thin plain ring, nowhere touching, inclined to the ecliptic."
Since that time discoveries have succeeded one another rapidly. "We have seen by degrees a ring evolved out of a triform planet, and the great division of the ring and the irregularities on it brought to light. Enceladus, and coy Mimas, faintest of twinklers, are caught by Herschel's giant mirrors. And he, too, first of men, realizes the wonderful tenuity of the ring, along which he saw those satellites travelling like pearls strung on a silver thread. Then Bond comes on the field, and furnishes evidence to show that we must multiply the number of separate rings we know not how many fold. And here we reach the golden age of Saturnian discovery, when Bond, with the giant refractor of Cambridge, and Dawes, with his 6-1/3-inch Munich glass, first beheld that wonderful dark semi-transparent ring, which still remains one of the wonders of our system. But the end is not yet: on the southern surface of the ring, ere summer fades into autumn, Otto Struve in turn comes upon the field, detects, as Dawes had previously done, a division even in the dark ring, and measures it, while it is invisible to Lassell's mirror—a proof, if one were needed, of the enormous superiority possessed by refractors in such inquiries. Then we approach 1861, when the ring plane again passes through the earth, and Struve and Wray observe curious nebulous appearances."[*]
[Footnote *: Lockyer.]