Part 13

“The South Pole of the moon lies in the midst of a marvelously upheaved and tumbled region, where one huge ring is seen breaking into another on every hand. One of these rings, named Newton—it lies just on the upper edge of the disk, south of Clavius—surrounds the deepest known depression on the moon. Its bottom sinks to a depth of 24,000 feet below the highest point on the wall. This gigantic hole is so profound that, situated where it is, close to the pole, where the sun can never rise very high, its depths remain forever buried in night. It is the very ideal of a dungeon, for if you were imprisoned at the bottom you would never see either the sun or the earth.”

“You make me shudder! Truly, after all, the moon appears to be a world filled with dreadful things. Who would ever imagine it, seeing how serene and beautiful she is in a calm night?”

“Yet is there not a kind of beauty even in those things, like the abyss of Newton, which appall you only when you know the real facts about them? There is a certain grace in their shapes and outlines, and a great attraction for the eye in their contrasts of light and shadow. It is the same sort of attraction which we find in such terrestrial scenes as the Yosemite Valley viewed from Inspiration Point, or the awful depths and chasms of the Grand Cañon of the Colorado. The presence of man and his works is not always essential in order to fix our attention upon the wonders of nature. Their very grandeur exalts us until we forget our little race and its ephemeral achievements.”

“Still, I hope that you will show me something on the moon less awe-inspiring and suited to awaken more quiet thoughts, and especially to reassure me concerning my lunarians, as I suppose you would call them.”

“You shall not be kept long in expectation. Turn your eyes once more to the Mare Imbrium. You will observe that its northern shore consists of a series of curves, each terminating with a promontory projecting into the sea. When looking at it I am often reminded of an entrancing view which I once enjoyed from the summit of Mt. Etna over the island of Sicily. From that great elevation nearly the whole eastern and southeastern coast of the island was visible as upon a map. The indented shore stretched away in long, graceful curves, where the blue Mediterranean contrasted sharply with the yellow sands, and the eye, wandering from Catania to Syracuse, was enchanted with the beauty of those geometric lines. But the winding coast of the Mare Imbrium is far longer than the shores of Sicily, and the mountains and cliffs bordering it are more wonderful than any corresponding scenes on the earth. I wish, particularly, to have you look at the easternmost of the indentations on the northern side of the mare. It bears a designation that must surely please your imagination. It is the Sinus Iridum, ‘Gulf or Bay of Rainbows.’”

“I recognize the work of my old friend the unknown astronomer. Verily he had a poetic soul! And he has written his poem on the chart of the moon, for those to read who can.”

“It is a charming landscape that the telescope reveals there,” I said, “even though no rainbows are visible.”

“But you will not deny that they may once have spanned that bay and its shores with their exquisite arches?”

“No, I shall not deny so pleasing a possibility. I will only say that it lies beyond the ken, and even outside the field, of science.”

“Then I regard it as fortunate that he was not too exclusive in his devotion to science, for then he could never have seen the rainbows with the eye of fancy, and your charts would not have been adorned with so delightful a name.”

“Let me tell you about this bay or gulf,” I said, tapping the photograph to recall her from her reverie. “You observe that it terminates at each end with a promontory. That at the western end is named Laplace, and the other Heraclides. The latter is the more picturesque. If ever you have an opportunity to see the moon with a good telescope do not fail to look at the promontory of Heraclides, for if you are fortunate in the choice of the time of observation when the setting sun is throwing its shadow over the adjoining ‘bay,’ you will find that the serrated outlines of the promontory represent, in a very striking manner, the profile of a woman, more sharply defined than the face of our familiar Moon Maiden, but a mere miniature in relative size. The shores of the Sinus Iridum are bordered with high cliffs, behind which rise the peaks of a mighty mountain mass. Just back of the center of the great bowed shore of the ‘bay’ appears, in the photograph, a small, bright crater ring. This bears the name of Bianchini. It is a lunar volcano, 18 miles in diameter, rising out of the midst of many ranges of nearly parallel hills and mountains, the general direction of which corresponds with that of the shore of the ‘bay.’ If there is any place on the moon where one is tempted to think that the scenes of a living world might once have been witnessed it is the Sinus Iridum and its neighborhood. Its latitude is between 40° and 50° north, corresponding with the most thickly populated zone of our own globe. The surface of the ‘bay’—once its bottom, if we admit that it was ever filled with water—is gently undulating, with winding ridges that suggest the action of tides and currents in sweeping to and fro deposits of sand and gravel, and piling them in long rows of bars and shallows. One can hardly help picturing in the mind’s eye waves breaking on the curving beach and dashing against the projecting rocks of the promontories; a white city seated just at the center of the shore of the ‘bay,’ near Bianchini, like Naples at the feet of Vesuvius; a rich vegetation covering the slopes of the mountain valleys, and romantic sails dotting the ‘bay’ and the neighboring ‘sea.’”

“I am very glad to observe,” interrupted my friend, “that you are not hopelessly prejudiced against my opinion that the moon has not always been ‘dead,’ as you call it.”

“I am so far from it,” I replied, “that I am half disposed to admit that she is not altogether dead even yet. But it is my duty to keep you as close as possible to the known facts. We shall see the Mare Imbrium and the neighborhood of the ‘Bay of Rainbows’ again. Meanwhile, suppose we turn to the next photograph of the series, No. 11. The age of the moon here is about thirteen days. She is fast approaching the phase of Full Moon. The first thing to which I would direct your attention now is the exceedingly brilliant point of light which has come into view near the terminator, a little north of east where the Mare Imbrium merges into the Oceanus Procellarum. In several ways this is the most noteworthy object on the moon. It led the famous English astronomer, Sir William Herschel, to believe that he had seen an active volcano on our satellite. He naïvely wrote in his notebook on a certain occasion: ‘The volcano glows more brightly to-night!’ Yet it is no more active than the other craters and crater rings in the lunar world. It is only extraordinarily, almost incredibly brilliant—by far the most dazzling point on the moon. It is a ring mountain, and is named Aristarchus. It has a near neighbor, barely visible in this photograph, close by toward the east named Herodotus. Herodotus is by no means remarkable for brilliancy. The central peak and a part of the floor and the east wall of Aristarchus consist of some material—nobody can tell what it is—which gleams in the sunlight, I had almost said like diamonds, although that would be an exaggeration. There are three or four other crater rings on the moon, including Proclus, which are also very brilliant, but not one of them can be regarded as a rival of Aristarchus. Its power of reflection is so great that it is even visible with a telescope in the lunar night, when the only light of any consequence that reaches it is that sent from the earth. It was, indeed, this fact which misled Herschel. He saw Aristarchus shining on the night side of the moon, and naturally thought that only the fires of an active volcano could have rendered it thus visible.”

NO. 11. DECEMBER 1, 1903; MOON’S AGE 12.98 DAYS. ]

“And are you sure that he was mistaken?”

“Positively. There is no fire in Aristarchus, and has been none for ages.”

“But why do not astronomers undertake to find out what it is that makes Aristarchus so brilliant, then?”

“They have almost no data to go upon. You should be informed that even the greatest telescopes, with their highest powers, are unable to bring the moon within less than an apparent distance of say forty miles. At such a distance it is manifestly impossible to tell of what a lunar formation consists. We cannot analyze the moon with the spectroscope as we can the sun and the stars, because she does not shine with her own inherent light. We can only infer that a large part of the substance of Aristarchus consists of something which reflects a very great proportion of the light that falls upon it. If a mountain on the earth were composed of a vast mass of crystals, or of bare polished metal, we might expect it to present, when seen from the moon, some such appearance as we notice when we look at Aristarchus.

“In this photograph the Sinus Iridum, having the sun higher above it, is more brilliantly illuminated than in No. 10. Particularly you will notice the brightness of the line of cliffs along its eastern curve, terminating at the promontory of Heraclides.”

“That is the promontory which presents the profile of a woman’s face, if I recall correctly what you told me.”

“Yes. Please observe also that the oval of Plato is as dark as ever, while Copernicus has, if possible, increased in brightness, and the great splatter of broken rays around it seems to have extended farther over the surrounding maria. Almost directly east of Copernicus, in the Oceanus Procellarum, appears a much smaller crater ring, Kepler, which resembles a miniature of Copernicus because it, too, is encircled with a kind of corona of short, bright rays. Copernicus, Kepler, and Aristarchus mark the corners of a large triangle. Speaking of rays recalls us to Tycho. You will see that, as I told you, this wonderful formation grows in relative prominence when the period of Full Moon approaches. Its ringed wall and central mountain are obscured by their own brilliance, while the gigantic system of bright bands, or rays, which have their center of origin at Tycho, is gradually becoming the master feature of the bright part of the moon.

“I have told you that the Mare Humorum, which is very sharply defined in the picture before us, is the darkest of all the level areas that go under the name of ‘seas.’ It is not, however, the darkest spot on the moon. There are several places where the surface appears, at times, much duskier than in any part of the Mare Humorum. Three or four of these are clearly discernible in this photograph. They lie westward from Copernicus in the Sinus Medii, the Sinus Æstuum, and the Mare Vaporum. Their dusky hue strikes the eye at once. They give the impression of sink holes. No special name is attached to them, but they must have been evident to the first observers, with the smallest telescopes, and it is rather surprising they should have escaped special designation on the lunar charts. A fact which will especially interest you is that some observers look upon these and other dusky areas on the moon as being, possibly, indications of the existence of some kind of vegetation there.”

“But if there is vegetation there may be other kinds of life also, may there not?”

“Ah, I have not said positively that there is vegetation, but if there is then your conclusion as to other life may be correct. Glance next at the upper part of the disk along the terminator. Two or three broad oval rings have come into view there. The largest of these with its long eastern wall lying exactly on the line between day and night is an extremely interesting formation, bearing the name of Schickard. The plain within the ring is almost large enough to have been called a ‘sea’ or at least a ‘lake.’ It is about 134 miles in diameter, and is in reality much more nearly circular than it appears to be. Like all similar formations situated near the ‘limb’ of the moon, by which we mean the edge as viewed from the earth, it is greatly foreshortened by perspective. The scale of the photograph is, unfortunately, not large enough to reveal an unique thing in the immediate neighborhood of Schickard, toward the southeast. I refer to what, as far as its telescopic appearance goes, might be described as an enormous bubble—a bubble 54 miles in diameter. Unlike the other formations the surface of this singular ring is elevated above the general level of the moon. When we come to examine it in detail it hardly answers, perhaps, to my designation of a bubble, since the edges are a little higher than the center, giving it the form of a shallow dish. If we could visit it we should find on approaching that we were climbing the slopes of what would seem to be a chain of low mountains, and on reaching the summit we should see before us an elevated circular plain, sinking gradually toward the middle. Filled with water it would form a shallow lake lying on the top of a broad, flat mountain. There is nothing else quite like it on the moon and certainly nothing on the earth.”

“It must have been a great curiosity in the days when the moon was inhabited, and I suppose that scientific ‘lunarians’ organized expeditions to explore it.”

“Perhaps, if you choose to regard it in that way. Now look again at the Mare Humorum. You perceive that its eastern side is lined with mountains and crater rings, while near the center of the northern border there is a conspicuous ring with a bright line running from the southern edge to the center. This is one of the most beautiful of lunar formations, and is named Gassendi. It is a favorite object for those who study the moon with telescopes on account of the great variety and singularity of the details visible within the ring. When you become a selenographer and possess your own telescope you will find few things more interesting to study than Gassendi.

“Next let us take up photograph No. 12. Here the moon is once more a little ‘older’ than before, and the sunrise line has again advanced a little eastward. This advance does not appear so rapid when the terminator is near the moon’s limb, because, on account of the rounding away of the lunar globe, the illuminated surface is foreshortened from our point of view on the earth. In this photograph you perceive that the wonderful shining mountain Aristarchus has become even brighter than it was before, or at least it is more conspicuous on account of the appearance of what seems to be a short ray shooting out from it in a southeasterly direction. There is also a light spot just below it which is caused by a little mountain group called the Harbinger Mountains. The bright ray connects Aristarchus with its neighbor Herodotus, of which I spoke a little while ago. There is a very remarkable feature of the moon here, not shown in the photograph, but to which I must briefly refer. It is an enormous cleft, or crack, or, if you please, cañon, which starts from Herodotus, whose northern wall seems to have been broken through to give passage to it, and goes winding across the surface of the Oceanus Procellarum with several sharp turns and angles for a total distance of nearly a hundred miles. What produced this remarkable chasm on the moon it is difficult to say. Some have suggested that it may once have been the bed of a river, but there are many serious objections to that view. Nevertheless, there seems to be little doubt that if we were to visit the moon we should find, in many ways, a striking resemblance between this prodigious cañon and that of the Colorado River.”

“And are not all these things so ancient, as far as you can tell, that, like the terrible volcanic rings, they might have been formed before the appearance of inhabitants upon the moon?”