Curiosities of the Sky

From the Preface

What Froude says of history is true also of astronomy: it is the most impressive where it transcends explanation. It is not the mathematics of astronomy, but the wonder and the mystery that seize upon the imagination. The calculation of an eclipse owes all its prestige to the sublimity of its data; the operation, in itself, requires no more mental effort than the preparation of a railway time-table.

The dominion which astronomy has always held over the minds of men is akin to that of poetry; when the former becomes merely instructive and the latter purely didactic, both lose their power over the imagination. Astronomy is known as the oldest of the sciences, and it will be the longest-lived because it will always have arcana that have not been penetrated.

Some of the things described in this book are little known to the average reader, while others are well known; but all possess the fascination of whatever is strange, marvelous, obscure, or mysterious - magnified, in this case, by the portentous scale of the phenomena.

The idea of the author is to tell about these things in plain language, but with as much scientific accuracy as plain language will permit, showing the wonder that is in them without getting away from the facts. Most of them have hitherto been discussed only in technical form, and in treatises that the general public seldom sees and never reads.

EXCERPT

The Windows of Absolute Night

To most minds mystery is more fascinating than science. But when science itself leads straight up to the borders of mystery and there comes to a dead stop, saying, "At present I can no longer see my way," the force of the charm is redoubled. On the other hand, the illimitable is no less potent in mystery than the invisible, whence the dramatic effect of Keats' "stout Cortez" staring at the boundless Pacific while all his men look at each other with a wild surmise, "silent upon a peak in Darien." It is with similar feelings that the astronomer regards certain places where from the peaks of the universe his vision seems to range out into endless empty space. He sees there the shore of his little isthmus, and, beyond, unexplored immensity.

The name, "coal-sacks," given to these strange voids is hardly descriptive. Rather they produce upon the mind the effect of blank windows in a lonely house on a pitch-dark night, which, when looked at from the brilliant interior, become appalling in their rayless murk. Infinity seems to acquire a new meaning in the presence of these black openings in the sky, for as one continues to gaze it loses its purely metaphysical quality and becomes a kind of entity, like the ocean. The observer is conscious that he can actually see the beginning of its ebon depths, in which the visible universe appears to float like an enchanted island, resplendent within with lights and life and gorgeous spectacles, and encircled with screens of crowded stars, but with its dazzling vistas ending at the fathomless sea of pure darkness which encloses all.

The Galaxy, or Milky Way, surrounds the borders of our island in space like a stellar garland, and when openings appear in it they are, by contrast, far more impressive than the general darkness of the interstellar expanse seen in other directions. Yet even that expanse is not everywhere equally dark, for it contains gloomy deeps discernable with careful watching. Here, too, contrast plays an important part, though less striking than within the galactic region. Some of Sir William Herschel's observations appear to indicate an association between these tenebrious spots and neighboring star clouds and nebulÊ. It is an illuminating bit of astronomical history that when he was sweeping the then virgin heavens with his great telescopes he was accustomed to say to his sister who, note-book in hand, waited at his side to take down his words, fresh with the inspiration of discovery: "Prepare to write; the nebule are coming; here space is vacant."

Among the topics touched upon are: