Lunar crater

“ In the lunar crater, known as Flammarion's Circle, a most typical branching crack is seen. An examination of these lunar cracks, of which I made drawings through the great telescope at the Lowell Observatory, showed them to be cracks of the most unmistakable character, paralleled on the Earth's surface, by sunbaked fissures. If volcanic forces have caused these cracks in the Moon the same kind of energy should have produced the same general results in Mars, and circular craters should equally be in evidence, for many of the lunar craters are sufficiently large to be detected were they on Mars. ”

“ The rays, which are of great brilliancy, appear to start, not exactly from the crater itself, but from a greyish area surrounding it, and they radiate in all directions over the surface, passing over, and almost completely masking in their course some of the largest of the lunar craters. ”

“ The abundance and size of craters testify to an effectual power of lunar volcanic action greatly exceeding anything with which we are familiar on the earth, but it must be borne in mind that, the force of gravity on the moon being only one-sixth of that of the earth, the height to which rocky matter would be thrown would be six times as great, and the crater walls proportionately extensive. ”

“ Klein, a German astronomer, has recently called the attention of astronomers to a lunar crater some three miles wide, which had not before been observed, and which, he feels sure, was not in existence two years ago. Astronomers have long since given up all hope of tracing either the signs of actual life upon the moon or traces of the past existence of living creatures there. But there are still among them those who believe that by sedulous and careful scrutiny processes of material change may be recognised in that seemingly inert mass. ”

“ We gather from the rather confused passage in which he describes this, and from a number of chance allusions and hints in other and subsequent messages, that this "great shaft" is one of an enormous system of artificial shafts that run, each from what is called a lunar "crater," downwards for very nearly a hundred miles towards the central portion of our satellite. These shafts communicate by transverse tunnels, they throw out abysmal caverns and expand into great globular places; the whole of the moon's substance for a hundred miles inward, indeed, is a mere sponge of rock. ”

“ But the most characteristic of all the lunar features are the crater mountains, which exist on a scale not only much larger relatively to the moon's globe than the scale on which terrestrial craters are formed, but much larger absolutely. ”

“ If a planet lacks great internal geologic forces, large craters can survive almost indefinitely. Such is the case for the Moon. Most of the volcanism and other activity on the Moon ceased 31⁄2 billion years ago, as the dating of lunar samples obtained by the Apollo astronauts showed. Since that time, the lunar surface has been passively accumulating impact scars. The longer any particular surface area has been exposed, the more densely packed are the craters. Thus crater density is the first thing a planetary geologist looks for in photos of a new world. ”

“ In order to approach a realization of the sublimity and grandeur of this magnificent example of a lunar volcanic crater, our reader would do well to endeavour to fix his attention on its enormous magnitude and attempt to establish in his mind’s eye a correct conception of the scale of its details as well as its general dimensions, which, as they so prodigiously transcend those of the largest terrestrial volcanic craters, require that our ideas as to magnitude of such objects should be, so to speak, educated upon a special standard. ”

“ Plan of the Peak of Teneriffe, showing how it resembles a lunar crater. (A. Geikie.)
"Here is a problem for you young astronomers to solve, as we learn more and more how to use the telescope with all its new appliances."
The crater itself is not so difficult to explain, for [Pg 16] we have many like it on our earth, only not nearly so large. In fact, we might almost say that our earthly volcanoes differ from those in the moon only by their smaller size and by forming mountains with the crater or cup on the top ”

“ The observer must not expect to see them all at once, however. The lunar features change their appearance to a surprising extent, in accordance with the direction of their illumination. Some great mountain-masses and ring-plains, or craters, which present scenes of magnificence when the sun is rising or setting upon them, disappear under a perpendicular light, such as they receive at full moon. The great crater-plain, known as Maginus, numbered 10 in our map, is one of these. ”

“ When the moon possessed sufficient heat for its volcanoes to be active, the earth was probably so hot that life was impossible on its surface. This supposition would point to an antiquity for the lunar craters far too great to be estimated by the centuries and the thousands of years which are adequate for such periods as those with which the history of human events is concerned. It seems not unlikely that millions of years may have elapsed since the mighty craters of Plato or of Copernicus consolidated into their present form. ”

“ Instead of being cavities in the summits of mountains, the lunar craters are rather gigantic sink-holes whose bottoms in many cases lie two or three miles below the general surface of the lunar world. ”

“ While we thus recognise the possibility, at any rate, that multitudes of small lunar craters, say from a quarter of a mile to two miles in diameter, may have been formed by falling meteoric masses hundreds of millions of years ago, and may have remained unchanged even until now, we perceive that on the moon later processes must have formed many small craters, precisely as such small craters have been formed on our own earth. ”

“ Many of the lunar craters are without doubt volcanic in origin, others seem to be ruins of molten lakes. Many thousands of the smaller ones appear as if formed by a violent pelting of the surface when semi-plastic, perhaps by enormous showers of meteoric matter. ”

“ Many underground streams are formed that find their way into the high-level chambers, which are thus supplied with pure water. The inhabitants of others have supplied themselves by tunnelling through into the upper parts of lofty chambers, that have their floors at the sea-level, and thus they tap the clouds themselves.”
“Our astronomers tell us that some of the Lunar craters are 60 or 80 miles in diameter or even more, which indicates that an enormously greater amount of volcanic action has taken place on the moon than on the earth. ”

“ The district on the southeast side is especially rich in them. Many somewhat radial ridges or spurs may be observed leading away from the exterior banks of the great rampart. They appear to be due to the freer egress which the extruded matter found near the focus of disruption.
Triesnecker. 150. A fine example of a normal lunar volcanic crater having all the usual characteristic features in great perfection. Its diameter is about 20 miles and it possesses a good example of the central cone and also of interior terracing. ”

“ Although several long ranges of mountains resembling those of the earth exist on the moon, the great majority of its elevations assume the crateriform aspect. Sometimes, instead of a crater, we find an immense mountain ring whose form and aspect hardly suggest volcanic action. But everywhere the true craters are in evidence, even on the sea-beds, although they attain their greatest number and size on those parts of the moon—covering sixty per cent of its visible surface—which are distinctly mountainous in character and which constitute its most brilliant portions. ”

“ Nothing but vast beds of glistering lava, now rough like immense piles of scoriae and clinker, now smooth like crystal mirrors, and reflecting the Sun's rays with the same intolerable glare. Not the faintest speck of life. A world absolutely and completely dead, fixed, still, motionless—save when a gigantic land-slide, breaking off the vertical wall of a crater, plunged down into the soundless depths, with all the fury too of a crashing avalanche, with all the speed of a Niagara, but, in the total absence of atmosphere, noiseless as a feather, as a snow flake, as a grain of impalpable dust. ”

“ Yet the Moon shows clearly that in the past it has gone through great and violent changes. The gradation is so complete from the little craterlets, which resemble closely, in form and size, volcanic craters on the Earth, up to the great ring-plains, like "Copernicus" or "Tycho," or formations larger still, that it seems natural to infer not only that the smaller craters were formed by volcanic eruption, like the similar objects with which we are acquainted on our own Earth, but that the others, despite their greater sizes, had a like origin. ”

“ They are mostly found on the eastern quarter of the floor. Some of them appear to have very slight rims, and in two or three instances small craters may be detected within them. Owing to their shallowness, they are very evanescent, and can only be glimpsed for an hour or so about sunrise or sunset. The large bright crater A, about 4 miles in diameter on the N.W. side of the interior, is by far the most conspicuous object upon it. Adjoining it on the N. is a large ring with a low border, and N. of this again is another, extending to the wall. ”

“ Eight above our heads, at a great height, opened the crater of a volcano from which escaped, from one quarter of an hour to the other, with a very loud explosion, a lofty jet of flame mingled with pumice stone, cinders, and lava. I could feel the convulsions of nature in the mountain, which breathed like a huge whale, throwing up from time to time fire and air through its enormous vents. ”

“ Athwart this world we were flying scarcely a hundred miles above its crests and pinnacles. And now we could see, what no eye on earth will ever see, that under the blaze of the day the harsh outlines of the rocks and ravines of the plains and crater floor grew grey and indistinct under a thickening haze, that the white of their lit surfaces broke into lumps and patches, and broke again and shrank and vanished, and that here and there strange tints of brown and olive grew and spread. ”

“ It was all moonshine, apparently a reflection of light from our earth, when sixteen times the amount of light showered on us at full moon is then thrown by us on her! But a hole through the middle of the moon, perhaps twenty miles round! There is no air that we know of on the half of the moon that we see, and there is no water. There are ample traces of volcanic fires that once lighted her surface, but they are all long gone out, and have left nothing behind for us but insoluble problems and mysterious wonders—a world of craters, lava, precipices, and cinders. ”

“ The crater also became more hollow, with its inner walls more inclined than the outer walls, and I had before me a formation strikingly analogous to the craters of the moon. The same phenomena were observed, whatever alloy I employed.
"Similar processes have possibly taken place on the moon. Instead of gas, the reliefs may have been produced by the vapors, which rose freely from the body while it was in a fluid state ”

“ The moon—the moon, so silver and cold,
Her fickle temper has oft been told,
Now shady—now bright and sunny—
But of all the lunar things that change,
The one that shows most fickle and strange,
And takes the most eccentric range,
Is the moon—so call'd—of honey! ”

“ Many years ago the great British explorer George Mallory, who was to die on Mount Everest, was asked why did he want to climb it. He said, "Because it is there."
Well, space is there, and we're going to climb it, and the moon and the planets are there, and new hopes for knowledge and peace are there. ”

“ The moonlight flooded that great, silent land. The reaped fields lay yellow in it. The straw stacks and poplar windbreaks threw sharp black shadows. The roads were white rivers of dust. The sky was a deep, crystalline blue, and the stars were few and faint. Everything seemed to have succumbed, to have sunk to sleep, under the great, golden, tender, midsummer moon. The splendor of it seemed to transcend human life and human fate. ”

“ The moon makes her circuit of the heaven in twenty-eight days plus about an hour, and with her return to the sign from which she set forth, completes a lunar month. ”

“ At first it had been an almost telescopic speck; it had brightened to the dimensions of the greatest star in the heavens; it had still grown, hour by hour, in its incredibly swift, its noiseless and inevitable rush upon our earth, until it had equaled and surpassed the moon. Now it was the most splendid thing this sky of earth has ever held. I have never seen a photograph that gave a proper idea of it. Never at any time did it assume the conventional tailed outline, comets are supposed to have. ”

“ It was a murky confusion—here and there blotted with a colour like the colour of the smoke from damp fuel—of flying clouds, tossed up into most remarkable heaps, suggesting greater heights in the clouds than there were depths below them to the bottom of the deepest hollows in the earth, through which the wild moon seemed to plunge headlong, as if, in a dread disturbance of the laws of nature, she had lost her way and were frightened. ”