Chapter 6

THE SCENERY OF THE MOON'S SOUTHERN HEMISPHERE

I now directed M'Allister to steer across the lunar equator into the southern hemisphere, and our attention was soon attracted by a very large walled plain on the eastward side of our course.

John asked me what it was called, and I explained that it was named Grimaldi, being also well known to observers as the darkest tinted of all the large lunar formations. As seen from the earth it appears a narrow ellipse, but we could see its full width, which is 129 miles, the length being 148 miles. It is also noteworthy as one of the few plains which are convex in section, and it is so large that its area is equal to the combined area of the whole of the counties of England south of the line of the Thames, including Cornwall.

I showed M'Allister this formation on our map, where it appears only a narrow ellipse in consequence of the moon's curvature, and pointed out how very different was its appearance now we could see over its whole extent. Other formations nearer to the moon's limb appear still more foreshortened when viewed from the earth.

John here remarked that "these large ring-plains covered immense areas, and, now that we could actually see them, their magnitude was more impressive than anything we could have imagined from merely hearing or reading about them."

"Yes, John," I said, "from our altitude of more than ten miles above the lunar surface we command a much more extensive view and gain a better knowledge of details than we could obtain even if we landed on the moon. For instance, if we could stand down in the centre of one of those very large rings, we should imagine we were in the midst of a boundless open plain. The mountains all around us would be so distant that, owing to the sharp curvature of the lunar sphere, they would all be below the horizon, notwithstanding the fact that many of them are several thousands of feet in height. So, for all we could see of them, those mountains might be non-existent.

"In the case of somewhat smaller rings we might perhaps see, here and there above the horizon, just the topmost peaks of some of the more lofty mountains."

M'Allister was now struck with an idea, and exclaimed, "Professor, I notice that many of these great walled plains are very flat, and I should think they would make fine golf-links, for there would be plenty of room to send the ball flying!"

"Undoubtedly," I answered, "you would have plenty of space for that; and I can tell you that you would be able to send the ball flying six times as far as you could on the earth with the same expenditure of force, because the moon's gravitation is only one-sixth of that of the earth."

"That would be grand," said M'Allister. "I should like to have a few turns at golf on the moon."

"Ah, but you would also have extra long tramps after your ball," I told him, "so you would get plenty of exercise; but, for the reason already mentioned, you would be able to get over the ground six times as easily."

"Well, Professor, I should not mind the distance in those circumstances," he answered jauntily.

"Perhaps you like jumping exercise too," I said. "Only fancy, M'Allister, if you wanted to jump across one of those narrower cracks! Why, if you could jump a distance of ten feet on the earth, you could jump sixty feet on the moon just as easily! Some of our athletes have jumped a length of twenty-six feet, so the same persons could with equal ease jump 156 feet on the moon! What do you think of that for a long jump?"

"Heh, Professor," he replied, looking rather bewildered, "what a jump! Why, I should think the mon was never coming down again!"

"I say, though, M'Allister, after all I am inclined to think you would not find golf on the moon altogether a pleasant game," said John.

"Why not, mon?" inquired M'Allister.

"Well," answered John, "I was thinking that if you sent your ball flying into one of those cracks which are several miles deep you would find yourself eternally 'bunkered,' for no niblick ever made would get you out of that."

M'Allister laughed so heartily at this idea of John's that we both joined in his mirth; then I recommended him to wait until we reached Mars if he wished to enjoy a game of golf, for there he would be sure to find enormous stretches of level ground.

Proceeding on our tour of inspection, we crossed the Ocean of Storms to a point near the central part of the lunar surface, and I showed them the fine walled plain called Ptolemaeus. This is 115 miles in diameter, and contains an area as large as the combined areas of Yorkshire, Lancashire, and Westmorland, its highest peak being 9000 feet in altitude. It forms the most northerly of a line of walled plains, the most southerly being Arzachel, which is sixty-six miles in diameter, and has a very depressed floor; while one peak on the walls rises to a height of 13,000 feet.

Passing farther west, we next examined another splendid group of three ring-mountains, arranged in a line running nearly north and south, viz. Theophilus, Cyrillus, and Catherina. The first is the most northerly, and is about sixty-four miles in diameter, with several very high peaks--one rising as much as 18,000 feet, and two on the opposite side being 16,000 and 14,000 feet high respectively. Even the central mountain is very large in area, and 6000 feet high. "That," I remarked to M'Allister, "is nearly half as high again as Ben Nevis, the highest mountain in Scotland, which is, after all, only 4400 feet high."

"Ben Nevis, Professor, is 4406 feet high!" corrected M'Allister.

"That's right, M'Allister," said John, clapping him on the back, "stick up for bonnie Scotland, and don't let her be robbed of that six feet of mountain!"

Proceeding, I then said that Cyrillus, the middle ring, was, as they could see, very irregular in shape; and the walls were in some parts very much broken and damaged.

Catherina is the largest of the three, being over seventy miles in diameter, and its highest peak is 16,500 feet in altitude.

I should have liked to have shown them the splendid double-walled plain called Petavius, which has a convex floor some 800 feet higher in the centre than at the edges. We were, however, too late both for that and Langrenus, another fine formation on the same meridian, for the sun had set upon them and they were in darkness, so it was no use going any farther in that direction.

We now directed our course over the Sea of Clouds till we arrived at what is known as the "Straight Wall."

"M'Allister," I said, "that ought to interest you, for there is a somewhat similar formation in Scotland. You see this is an escarpment, or cliff, over sixty miles long, and varying from about 600 feet to 900 feet in height.

"This cliff is one of the best known examples on the moon of what in geology is termed a 'fault,' indicating either that one part of the general surface has been greatly elevated, or that the adjoining part has been depressed. We have many examples of such 'faults' on the earth--for instance, one runs a long way across Scotland, from Stonehaven round to Helensburgh, between the Highlands and the Lowlands, and is about 120 miles in length. That is about twice the length of the Straight Wall; so you see that Scotland can beat the moon in that respect!"

This brought M'Allister up to the scratch. "Scotland," he exclaimed excitedly, "can hold her own in most things! Why, mon, the empire is indebted to her for the finest statesmen, the cleverest lawyers, the best engineers and scientists, and, allow me to say, the bravest soldiers in the whole world! Scotsmen go everywhere, and can do anything!"

"Oh yes, M'Allister," said John, with a laugh, "and a Scotsman has got to the moon! but, please, do not forget that two Englishmen planned the trip, and devised the means of accomplishing the journey!"

M'Allister smiled a rather wintry smile, and then subsided. John was a bit too smart for him that time.

Passing on, we inspected the large cleft running parallel to the Straight Wall, and the small mountain close by named after Birt, the well-known selenographer. We then crossed the Sea of Clouds again, and had a long look at the great system of straight clefts near Campanus and Hippalus, together with the fine walled plain Gassendi, the floor of which is at some parts 2000 feet above the lunar surface. I had often studied this through the telescope, as it is a most interesting formation.

"Well, Professor," remarked M'Allister, "I have travelled nearly all over our own world, but in all my journeyings I have never seen such wild and rugged scenery as I have during the few hours we have been passing over the moon. The mountains seem to be split and rent in all directions, especially where there are volcanic craters in the neighbourhood--and, really, they seem to be everywhere; while landslips are very numerous, and the mountain passes are extremely rugged and gloomy."

"Yes," I replied, "my telescopic observations had prepared me for a great deal, but the weird ruggedness of the lunar scenery exceeds all my anticipations."

"What is the explanation of it all?" M'Allister inquired.

"I should think, M'Allister, that much of it was originally caused by the extreme violence of volcanic outbursts," I answered; "but the excessive expansion and contraction, resulting from the alternate spells of intense heat and intense cold to which the moon is continually exposed, will account for the formation of many of those tremendous chasms and precipices which we see everywhere around us, as well as for the huge mounds of dislodged rocks and _debris_, which are piled up in such chaotic confusion on the ledges of the mountains and round their bases.

"On the earth such _debris_ would very soon have become smoothed by atmospheric erosion, the interstices would have been filled up with dust and soil, while the growth of vegetation would have added a new charm to the effect.

"You have seen the great landslip in the Isle of Wight! When it fell all was wild desolation, but it has become covered with such a luxuriant growth of vegetation that it now presents a scene of beauty.

"On the moon, however, there is neither atmosphere, rain, nor moisture to produce weathering of the rocks or to encourage the growth of vegetation; so the rocks remain just as sharp, rugged, and bare as they were ages ago when they were first split off from the mountains.

"No doubt very large masses of rocks are still frequently being dislodged, and if we could see them falling from the upper part of a mountain, rebounding along the spurs, with fragments flying in all directions and ultimately dashing to pieces at the base, it would seem to us most uncanny not to hear the slightest sound arising from all this apparent commotion. Without an atmosphere, however, no sound could be produced, no matter how many thousands of tons of rock might fall to the ground.

"Tremendous changes of this nature may be happening on the moon, but our telescopes are not powerful enough to enable us to see the results. They would have to cover an area of miles to be noticeable, unless they presented some particularly striking configuration."

"Professor," exclaimed M'Allister, "how is it that all the shadows on the moon are such a dense black and so sharply defined at the edges?"

"That," I exclaimed, "is entirely owing to the absence of the atmosphere. On the earth, even at night time, some light is diffused by our atmosphere, and shadows are never dense black even when thrown by a bright sun. On the moon it is black darkness everywhere outside the direct rays of the sun, and there is no gradual diminution of the darkness about the edges of shadows such as we see on the earth. The only mitigation of the blackness is seen where some light is reflected across from the rocky walls on which the sun is shining.

"In those deep recesses down at the bases of the mountains the cold must be most intense and the darkness truly awful. It all looks very nice when the sun is shining, but appearances are often deceptive, and do not improve on a closer acquaintance."

We could not have landed upon the moon if we had desired to do so, for no provision had been made for a supply of air by means of helmets and other apparatus. I kept my own counsel in this matter, as I had very good reasons for discountenancing any proposal to investigate the lunar scenery too closely.

By a curious coincidence, not long after this conversation we had ocular demonstration of the fact that the moon is liable to changes from other agencies than those of expansion and contraction.

We were looking at some distant mountains which were in the full sunshine. Suddenly a dark shadowy looking mass shot across the sky and struck one of the mountain peaks some distance down from the top. The peak seemed to be immediately demolished, and vanished from our sight!

M'Allister gazed spellbound; but John excitedly exclaimed: "Did you see that, Professor? One moment the peak was there, and the next moment it was gone!"

"Yes," I said. "Undoubtedly that dark shadow was a large meteoric stone. Many have fallen on our earth at various times, some being tons in weight. Usually, however, they are so small that on entering our atmosphere they become fused by the friction and changed to dust. Larger ones are partially fused, and often split into fragments in the upper air. The moon, having no atmosphere, is quite unprotected in this respect; and meteorites moving at enormous speeds, probably over forty miles in a second, travel unchecked and unaltered in character until they strike the lunar surface. It is estimated that immense numbers constantly enter our atmosphere and are destroyed; but the moon must be continually exposed to bombardment by meteorites of considerable size.

"Many of our ships have been lost at sea in calm weather, and their fate has remained a profound mystery; but it is not at all improbable that some of them have been destroyed by large meteorites, for several instances are recorded of ships having very narrow escapes from these dangerous missiles from outer space."

Passing on towards the south-west, we had a long look at the magnificent formation named Tycho. It is a ring-plain nearly fifty-six miles in diameter, the mountain walls having some peaks over 17,000 feet in height. I drew their attention to the long bright ray-streaks which radiate in all directions for many hundreds of miles from the neighbourhood of this formation, to which I alluded when we had been looking at the rays from Proclus. Tycho and these bright streaks can be seen from the earth when the moon is full without the aid of a telescope, if one possesses good eyesight.

An enormous number of ring-plains and ring-mountains exists all over the southern half of the moon's disc; in many cases there are rings within rings, and others where they have overlapped or cut into previously formed rings.

Moving almost due south, we passed the large but partially ruined walled plain known as Maginus. This ring has a floor which is no less than 14,000 feet below the lunar surface. We then arrived at that favourite object for telescopic observers which is named Clavius. This is an enormous ring-plain, being over 142 miles in diameter, and encloses an area of 16,000 square miles, thus being half the area of Scotland. It has a very depressed floor, and some of the mountains are 16,000 to 17,000 feet in altitude.

Farther on, and close to the south pole, we saw the very deepest of the lunar walled plains, which is named after Newton, who possessed probably the deepest intellect of any of our astronomers. A smaller formation south of Plato was originally named after him, but was not considered worthy of a man of his scientific eminence, so the name was transferred to the formation we were looking upon. It is about 143 miles long and very irregular in shape, and its depth is about 24,000 feet--so deep, in fact, that the sun's light never reaches to the bottom; thus, when we look at it from the earth, the floor is always in shadow.

The Leibnitz Mountains, unfortunately, were not visible, as the sun had set upon them. I, however, mentioned that this range comprises several peaks which are believed to be the highest on the lunar surface, reaching as they do an altitude of 30,000 feet, and, according to some measurements, 40,000 feet. They are very difficult to measure, owing to the fact that they are really situated on the farther side of the moon, extending east and west of the south pole, and are only occasionally brought into view by the moon's libration; even then they are seen in profile, and so situated that they cannot be measured with certainty. They are, however, so high that they blunt the southern cusp of the moon when it is in crescent form.

I now directed M'Allister to turn the vessel in a north-easterly direction, and we moved across to the last objects which I proposed to examine. One was the large walled plain "Schickard"--about 135 miles in diameter--which encloses several other rings; the other, which lies to the south-east of it and close to the moon's south-eastern limb, is probably the most unique object on the lunar surface. As we gazed upon it I explained that the formation, which is known as "Wargentin," would probably in the usual course of events have been a ring-plain about fifty-four miles in diameter, but it really is a high plateau of that size, with very low ramparts. It is evidently a ring-plain which became filled to the brim with lava, or mud, that welled up from the interior of the moon; and the mountain walls, being exceptionally strong and without any breaks or gaps, withstood the enormous pressure of the lava, which therefore solidified and formed the great plateau as we now see it. The low ramparts, which we noticed here and there, are really the isolated peaks and ridges of the mountains forming the walls. This is the only known instance of such a formation; but probably others would exist had not the walls of the rings given way under the pressure of the lava. The walls of several ring-plains have been quite carried away, and, in some cases so obliterated, that it is now difficult to make out the original shape of the rings.

Having taken a last look at this unique object, I directed M'Allister to set the machinery in motion and rise for the purpose of quitting the moon.

"But," interposed John, "are you not going to have a look at the back of the moon, Professor?"

"No, John," I answered, "only a small portion of it is now in the sunlight, the rest is in the blackest darkness, so we should not be likely to learn much more about it than we know at present."

"Do you think the moon is inhabited?" he then asked.

"No, I do not think it is; no sign of life has ever been discovered, and we have seen nothing to indicate its existence here. The prevailing conditions seem to preclude the possibility. Think, John, if there is any life, what must it be! Without any atmosphere--therefore, not a sound to be heard, for all would ever be in the most deathly silence--no breath of wind; never a cloud nor a drop of refreshing rain, nor even dew; intense heat in the sunlight and the most intense cold everywhere in the shade! If any life does exist, it is most probably down in those gloomy, dark and cold recesses at the bottom of the ring-mountains, where there may possibly be some remains of an atmosphere. It would, however, be life in such a dreadful and debased form that I would rather not think about it at all.

"For a somewhat similar reason, I have directed M'Allister to keep the _Areonal_ at least ten miles above the lunar surface all the time we have been passing over it. When we saw it from a distance it was, as you know, an object of surpassing beauty; and as we have seen it from here it has still been pleasant to look upon. This is truly a case where distance lends enchantment to the view; for, if we went down close to the surface, we should find it a scene of the weirdest and wildest desolation--more horrible than anything seen during a nightmare, and more terrible than anything imagined by the insane!

"No, John," I concluded, "let us retain our memory of the moon as a thing of beauty, and leave it at that."

"I quite agree with your view of the matter, Professor," John replied; so I gave the signal to M'Allister, who was awaiting the result of our discussion, and we soon left the moon far below us.