 CHAPTER 10 STRANGE ADVENTURES OF COMETS The fears and legends of ancient times before science was born and the superstitions of the dark ages, seduously cultivated for theological purposes by monks and priests, have so colored our ideas of the influence that comets have had upon the human mind that many readers may be surprised to learn that it was the apparition of a wonderful comet that of 1843, which led to the foundation of our greatest astronomical institution, the Harvard College Observatory. No doubt the comet superstition existed half a century ago, as indeed it exists yet today, but in this case the marvelous spectacle in the sky proved less effective in inspiring terror than awakening a desire for knowledge. Even in the 16th century, the views that enlightened minds took of comets tended powerfully to inspire popular confidence in science, and Halley's prediction after seeing and studying the motion of the comet, which appeared in 1682, that it would prove to be a regular member of the Sun's family, and would be seen returning after a period of about 76 years, together with the development of that prediction, produced a revulsion from the superstitious notions which had so long prevailed. Then the facts were made plain that comets were subject to the law of gravitation equally with the planets, that there are many which regularly return to the neighborhood of the Sun, perihelion, and these travel in orbits differing from those of the planets, only in their greater eccentricity. Although they have the peculiarity that they do not like the planets, all go around the Sun in the same direction, they do not keep within the general plane of the planetary system, but traverse it sometimes from above and sometimes from below. Other comets, including most of the great ones, appear to travel in a parabolic or in few cases hyperbolic orbits, which, not being closed curves, never bring them back again. But it is not certain that these orbits may not be extremely eccentric ellipses, and that after the last of hundreds or thousands of years, the comets that follow them may not reappear. The question is an interesting one, because if all orbits are really ellipses, then all comets must be permanent members of the solar system. While in the contrary case, many of them are simply visitors seen once and never be seen again. The hypothesis that comets are originally interlopers might seem to derive some support from the fact that certainly periodic ones are associated, in groups, with the great outer planets, whose attraction appears to have served as a trap for them by turning them into elliptical orbits, and thus making them prisoners in the solar system. Jupiter, owing to his great mass and his commanding situation in the system, is the chief comet catcher, but he catches them not for himself, but for the sun. Yet, if comets do not come originally from without the borders of the planetary system, it does not by any means follow that they were wanderers at large in space before they yielded to the overmastering attraction of the sun. Investigation of the known cometary orbits, combined with theoretical considerations, has led some astronomers to the conclusion that as the sun travels onward through space, he picks up in route cometary masses, that belong strictly to his empire, are born along in the same vast cosmical current that carries the solar system. But while no intelligent person any longer thinks that the appearance of a great comet is a token from the heavenly powers of the approaching death of a mighty ruler, or the outbreak of a devastating war, or the infliction of a terrible plague upon wicked mankind, science itself has discovered mysteries about comets, which are not less fascinating, because they are more intellectual than irrational fancies than they have displaced. To bring the subject properly before the mind, let us see what the principal phenomena connected with the comet are. At the present day, comets are ordinarily picked up, with the telescope or the photographic plate before anyone except their discoverer is aware of their existence, and usually they remain so insignificant in appearance that only astronomers ever see them. What's so great is the prestige of the word comet, that the discovery of one of these inconspicuous wanderers and its subsequent movements become items of the day's news which everybody reads with the feeling, perhaps that at least he knows what is going on in the universe even if he doesn't understand it. But a truly great comet presents quite a different proposition. It too is apt to be detected coming out of the depths of space before the world at large can get a glimpse of it. But as it approaches the sun, its aspect undergoes a marvelous change. Agitated, apparently by solar influence, it throws out a long streaming tail of nebulous light, directed away from the sun and looking as if blown out like a pen in by a powerful wind. Whatever may be the position of the comet with regard to the sun, as it circles around him, it continually keeps its tail on the offside. This as we shall soon see is a fact of the capital importance in relation to the probable nature of comet's tails. Almost at the same time that the formation of his tail is observed, a remarkable change takes place in the comet's head, which, by the way, is invariably and not merely occasionally its most important part. On approaching the sun, the head usually contracts. Coincidentally, with this contraction, a nucleus generally makes its appearance. This is a bright star-like point in the head and it probably represents the totality of the sub-matter that the comet faces. But it is regarded as extremely unlikely that even the nucleus consists of a uniformly solid mass. If it were such, comets would be far more formidable visitors when they pass near the planets than they have been found to be. The diameter of the nucleus may vary from a few hundred up to several thousand miles. The heads, on average, are from 25,000 to 100,000 miles in diameter. Although a few have greatly exceeded these dimensions, that of the comet of 1811, one of the most stupendous ever seen, was a million and a quarter miles in diameter. As to the tails notwithstanding their enormous length, some have more than a hundred million miles long, there is reason to believe that they are of extremity as rare as a vacuum. The smallest stars have been seen shining through their most brilliant portions with undiminished luster. After the nucleus is formed, it begins to throw out bright jets directed towards the sun. A stream, and sometimes several streams of light, also projects sunward from the nucleus, occasionally appearing like a stunted tail directed oppositely the real tail. Symmetrical envelopes, which seen in section, appear as half circles or parabolas, rise sunward from the nucleus, forming concentric series. The ends of these stream backwards into the tail, to which they seem to supply material. Ordinarily, the formation of these ejections and envelopes is attended by intense agitation of the nucleus, which twists and turns, swinging and gyrating with an appearance of the greatest violence. Sometimes the nucleus is seen to break up into several parts. The entire heads of some comets have been split asunder and passing close around the sun. The comet of 1882 retreated into space after its perihelium passage with the five heads instead of the one that it had originally. And each of these heads had its own tail. The position of the spectroscope has enabled astronomers during later years to study the chemical composition of comets by analyzing their light. At first, the only substances thus discovered in them were hydrocarbon compounds, due evidently to the gavacius envelopes in which some combinations of hydrogen with carbon existed. Behind this gaseous spectrum was found a faint continuous spectrum ascribed to the nucleus, which apparently both reflects the sunlight and gives forth the light of a glowing solid or liquid. Subsequently, sodium and iron lines found in cometary spectra. The presence of iron would seem to indicate that some of these bodies may be much more massive than observations on their attractive effects have indicated. In some recent comets, such as Morehouse's in 1908, several lines have been found, the origin of which is unknown. Without going back to the 19th century, we may find records of some of the most extraordinary comets that man has ever looked upon. In 1811, still spoken of as the year of the comet, because of the wonderful vintage ascribed to the sky visitor, a comet shape like a gigantic sword amazed the world and, as it remained visible for 17 months, was regarded by superstitious persons as a symbol of the fearful happenings of Napoleon's Russian campaign. This comet, the extraordinary size of whose head, greatly exceeding that of the sun itself, has already been mentioned. Was also remarkable for exhibiting so great a brilliancy without approaching even to the Earth's distance from the sun. But there was once a comet and only once in the year 1729, which never got nearer to the sun than four times the distance to the Earth and yet appeared as formidable object in the sky. As Professor Young has remarked, it must have been an enormous comet to be visible from such a distance. And we are to remember that there were no great telescopes in the year 1729. That comet affects the imagination like a phantom of space peering into the solar system, displaying its enormous train of far-off, which, if it as approaches near as the comets, would have probably become the celestial wonder of all human memory, and then turning away and vanishing into the depths of immensity. In 1843, a comet appeared which was so brilliant that it could be seen in broad day close beside the sun. This was the first authenticated instance of that kind, but the occurrence was to be repeated as we shall see in a moment less than 40 years later. The splendid comet of 1858, usually called Donates, is remembered by many persons yet living. It was perhaps both a scene by the naked eye and with the telescope, the most beautiful comet of which we have any recurred. It, too, marked a rich vintage year, still remembered in the vineyards of France, where there is a popular belief that a great comet ripens the grape and imparts to the wine the flavor not attributable by mere skill of the cultivator. There are comet wines carefully treasured in certain cellars and brought forth only when their owner wishes to treat his guests to a sip from paradise. The year 1861 saw another very remarkable comet of an aspect strangely vast and diffuse, which is believed to have swept the earth with its immense tail when passed between us and the sun on the night of June 30th, an event which produced no other known effect than the appearance of an unwanted amount of scattered light in the sky. The next very notable comet was the great southern comet of 1880, which was not seen from the Northern Hemisphere. It mimicked the aspect of the famous comet of 1843 and to the great surprise of astronomers appeared to be traveling in the same path. This proved to be the rising of the curtain for an astronomical sensation unparalleled in its kind. For two years later another brilliant comet appeared, first in the Southern Hemisphere and it too followed the same track. The struggling suggestion was now made that this comet was identical with those of the 1843 in 1880. Its return having been hastened by the resistance experienced in passing twice through the coronal envelope. And there were some who thought that it would now swing swiftly round and then plunge straight into the sun with consequences that might be disastrous to us on account of the flash of the heat that would be produced by the impact. Nervous people were frightened but observations soon proved that the danger was imaginary for although the comet almost grazed the sun it must have rushed through two or three million miles of the coronal region. No retardation of its immense velocity was perceptible and it finally passed away in a damaged condition as before remarked it has never since appeared. Then the probable truth was perceived that the three comets 1843, 1880 and 1882 were not one identical body but three separate ones all traveling in the same orbit. It was found to the comet seen in 1668 for similar insignia of relationship. The natural inference was that these four bodies had once formed a single mass that had been split apart by the destructive action of the sun. Strength was lent to this hypothesis by the fact that the comet of 1882 was apparently torn asunder during its perihelion passage retreating into space in a diseavored state. But Professor George Forbes has a theory that splitting of the original cometary mass was affected by an unknown planet probably greater than Jupiter situated at a hundred times the Earth's distance from the sun and revolving in a period of a thousand years. He supposes that the original comet was not that of 1668 but one seen in 1556, which has since been missing and its destruction occurred from an encounter with a sepitious planet about the year 1700. Truly from every point of view comets are the most extraordinary adventurers. The comet of 1882 was likewise remarkable for being visible like its predecessor of 1843 in full daylight in close proximity to the sun. The story of its detection when almost in contact with the solar disk is dramatic. It had been discovered in the southern hemisphere only a couple weeks before its perihelion which occurred on September 17th and on the forenoon of that day it was seen by Dr. Common in England and by Dr. Elkin, Mr. Finlay and the Cape of Good Hope almost touching the sun. It looked like a dazzling white bird without spread wings. The southern observers watched it go right into the sun. What it instantly disappeared. What had happened was that the comet in passing its perihelion point had swung exactly between the earth and the sun. On the following morning it was seen from all parts of the world close by the sun on the opposite side and it remained thus visible for three days gradually receding from the solar disk. It then became visible for northern observers in the morning sky before sunrise brandishing a portentous sword-shaped tail which, if it had been in the evening sky, would have excited the wonder of hundreds of millions but situated where it was comparatively few ever saw it. The application of photography to the study of comets has revealed many curious details which might otherwise have escaped detection or at best have remained subject to doubt. It has in particular shown not only the precise form of the tails but remarkable visuities that they undergo. Professor Bernard's photographs of Brooke's Comet in 1893 suggested by the extraordinary changes in the form of the tail which they revealed that the comet was in countries of obstructions in space which bent and twisted its tail into fantastic shapes. We will observe the strange form into which the tail was thrown on the night of October 21st. A cloud of meteors through which the comet was passing might have produced such deformations of its tail. In the photograph of Daniel's Comet of 1907, a curious striping of the tail will be noticed. The short, bright streaks seen in the photograph, it may be explained, are the images of stars which are drawn out into lines in consequence of the fact that the photographic telescope was adjusted to follow the motion of the comet while the stars remained at rest. But the adventures of comets are not confined to possible encounters with unknown obstacles. We have referred to the fact that the great planets and especially Jupiter frequently interfere with the motions of comets. This interference is not limited to the original alteration of their orbits from possible parabolas to ellipses but is sometimes exercised again and again turning the bewildered comets into elliptical paths of all degrees of eccentricity. A famous example of this kind of planetary horse play is furnished by the story of Lexel's missing comet. This comet was first seen in 1770. Investigation showed that it was moving in an orbit which should bring it back to the perihelion every five and a half years. Yet it had never been seen before and although often searched for has never been seen since. Lapis and Levite proved mathematically that in 1767 it approached so close to Jupiter as to be involved among the orbits of its satellites. What its track had been before is not known but on that occasion the giant planet sized interloper threw it into a short-lipped agorbit and sent it like an arrested vagrant to receive the sentence at the bar of the sun. On this journey it passed within less than 1.5 million miles of the earth. The form of orbit which Jupiter had impressed required as we have said its return in about five and a half years. But soon after 1770 it had the misfortune a second time to encounter Jupiter at close range and he, as if dissatisfied with the leniency of the sun or indignant at the stranger's familiarity seized the comet and hurled it out of the system or at any rate so far away that it has never since been able to rejoin the family circle that passed in the immediate rays of the solar hearth. Nor is this the only instance in which Jupiter has dealt summarily with small comets that have approached him with too little deference. The function which Jupiter so conspicuously fulfills as master of the hounds to the sun is worth considering a little more in detail. To change the figure imagine the sun in its voyage through space to be like a majestic battleship surrounded by its scouts. Small vessels, the comets as they are overhauled by the squadron are taken in charge by the scouts with Jupiter for their chief and are forced to accompany the fleet but not all are impressed. If a strange comet undertakes to run across Jupiter's vows, the latter brings it to and makes prize of it by throwing it in a relatively small ellipse with the sun for its focus. Thenceforth, unless this happened to the unhappy comet of Lexel, it encounters Jupiter again in such a way as to be diverted by him into a more distant orbit. It can never get away. About 30 comets are now known to have thus been captured by the great planet and they are called Jupiter's comet family. But on the other hand, if a wandering comet crosses the wake of the chief planetary scout, the latter simply drives it away by accelerating motion and compels it to steer off into open space. The transformation of comets into meteors will be considered in the next chapter. But here in passing, mention may be made of the strange fate of one member of Jupiter's family. VA-less comet, which having become over-bold in its advances to its captor was, after a few revolutions in its impressed orbit, torn to pieces and turned into a flock of meteors. And now, let us return to the mystery of comets' tales. That we are fully justified in speaking of the tales of comets as mysterious is proved by the declaration by Sir John Herschel, who averred in so many words that there is some profound secret and mystery of nature concerned in this phenomenon. And this profound secret and mystery has not yet altogether been cleared up. Nevertheless, the all-explaining hypothesis of Arius offers us once more a certain amount of aid. Comet's tales, Arius assures us, are but another result of the pressure of light. The rule recalls the applications of this theory to the zodiacal light and the aurora. In the form in which we now have to deal with it, the supposition is made that as a comet roaches the sun, eruptions of vapor due to solar heat occur in its nucleus. These are naturally most active on the side, which is directly exposed to the sun, once the appearance of the immense glowing envelopes that surround the nucleus on the sunward side. Among the particles of hydrocarbon and perhaps solid carbon in the state of fine dust, which are thus set free, there will be many whose size is within the critical limit, which enables the light waves from the sun to drive them away. Clouds of such particles then will stream off behind the advancing comet, producing the appearance of a tail. This accounts for that that the tails of comets are always directed away from the sun, and it also explains the varying forms of the tails and the extraordinary changes that they undergo. The speed of the particles driven before the light waves must depend upon their size and weight, the lightest of a given size traveling the most swiftly. By accretion, certain particles must grow, thus losing velocity and producing the appearance of bunches in the tail, such as have been observed. The hypothesis also falls in with researchers of Brickton who have divided the tails of comets into three principal classes. One, those who appear as long, straight rays. Two, those which have the form of curved plumes or scimitars. Three, those which are short, brushy and curved shortly backward along the comet's path. In the first type, he calculates the repulsive force at from 12 to 15 times the force of gravity. In the second, at from two to four times, and in the third, about one and a half times. The straight tails he ascribes to hydrogen because hydrogen atom is the lightest known. The short-shaped tails to hydrocarbons and the stumpy tails to vaporized iron. It will be seen that if the force driving off the tails is that which Arius assumes it to be, the forms of those appendages would accord with those of the Brickton theories called for. At the same time, we have an explanation of the multiple tails with which some comets have adorned themselves. The comet of 1744, for instance, had at one time no less than seven tails spread in a wide curved brush behind it. Donati's comet of 1858 also had at least two tails. The principal one sword-shaped and the other long, narrow and straight as a rule. According to Brickton, the straight tail must have been composed of hydrogen and the other of some form of hydrocarbon whose atoms are heavier than those of hydrogen and consequently once dweighed by the storm of light waves followed the curvature depending upon the resultant forces operating upon them. The seven tails of the comet of 1744 presented a kind of diagram graphically exhibiting its complex composition. If we knew a little more about the constituents of the comet, we might be able to say from the amount of curvature of the different tails just what were the seven substances of which that comet consisted. If these theories seem to be rather fantastic, at any rate, there are no more fantastic than the phenomena that they seek to explain. N, chapter 10, Greg Bell, Katie, Texas. Chapter 11 of Curiosities of the Sky. This is a LibriVox recording. All LibriVox recordings are in the public domain. For more information or to volunteer, please visit LibriVox.org. Recording by Greg Bell. Curiosities of the Sky by Garrett Service. Chapter 11, Meteors, Fireballs, and Meteorites. One of the most terrorizing spectacles with which the heavens have ever caused the hearts of men to quake occurred on the night November 13th, 1833. On that night, North America, which faced the storm, was under a continual rain of fire from about 10 o'clock in the evening until daybreak. The fragments of a comet had struck the earth. But the meaning of what had happened was not discovered until long afterward. To the astronomers, who, with astonishment, not less than that of other people, watched the wonderful scene, it was an unparalleled shower of meteors. They did not then suspect those meteors had once formed the head of a comet. Light dwarfed when, a year later, Professor Denison Olmsted of Yale College demonstrated that the meteors had all moved in parallel orbits around the sun, and that these orbits intersected that of the earth at the point where our planet happened to be on the memorable night of November 13th. Professor Olmsted even went so far as to suggest that the cloud of meteors that they had encountered the earth might form a diffuse comet, but full recognition of the fact that they were cometary debris came later as a result of further investigation. The key to the secret was plainly displayed in the spectacle itself, and was noticed without being understood by thousands of the terror-strickened beholders. It was an umbrella of fire that had opened overhead and covered the heavens. In other words, the meteors all radiated from a particular point in the constellation Leo, and being countless as the snowflakes in a winter tempest, they ribbed the sky with fiery streaks. Professor Olmsted showed that the radiation of the meteors from a fixed point was an effective perspective, and in itself, a proof that they were moving in parallel paths when they encountered the earth. The fact was noted that there had been a similar, but incomparably less brilliant display of meteors on the same day of November, 1832, and it was rightly concluded that these had belonged to the same stream. Although the true relationship of the phenomena was not immediately apprehended, Olmsted ascribed to the meteors revolution about the sun once in every six months, bringing them to the intersection of their orbit with that of earth every November 13th. But later investigators found that the real period was about 33 and one-quarter years, so that the great displays were due three times in a century, and their return was confidently predicted for the year 1866. The appearance of the meteors in 1832, a year before the great display, was ascribed to the great length of the stream which they formed in space. So great that they required more than two years to cross the earth's orbit. In 1832, the earth had encountered a relatively rare part of the stream, but in 1833, on returning to the crossing place, it found they were the richest part of the stream pouring across the orbit. This explanation also proved to be correct, and the predicted return in 1866 was duly witnessed, although the display was less brilliant than in 1833. It was followed by another in 1867. In the meantime, Olmsted's idea of commentary relationship of the meteors was demonstrated to be correct by the researchers Shapali and others, who showed that not only the November meteors, but those of August, which are seen more or less abundantly every year, traveled in the tracks of well-known comets and had undoubtedly an identical origin with those comets. In other words, the comets and the meteor swarms were both remnants of the original masses, which had probably been split up by the action of the sun or of some planet to which they made so close approaches. The annual curiosity of the August meteors was ascribed to the fact that the separation had taken place so long ago that the meteors have become distributed all around the orbit, in consequence of which the earth encountered some of them every year when it arrived at the crossing point. Then, Levier showed that the original comet associated with the November meteors was probably brought into the system by the influence of the planet Uranus in the year 126 of the Christian era. Afterward, Alexander Herschel identified the tracks of no less than 26 meteor storms, most of them inconspicuous, with those of the comets. The still more recent researches of Mr. W. F. Denning made it probable that there are no meteors which do not belong to a flock or system, probably formed by the disintegration of a cometary mass. Even the apparently sporadic ones which shoot across the sky as lost souls of the night bring members of flocks which have become so widely scattered that the earth sometimes takes weeks to pass through the region of space where their paths lie. The November meteors should have exhibited another pair of spectacles in 1899 and 1900, and their failure to do so caused at first much disappointment. Until it was made plain that a good reason existed for their absence. It was found that after their last appearance in 1867, they had been disturbed in their movements by the planets Jupiter and Saturn, whose attractions had had chose shifted the position of their orbit that it no longer intersected that of the earth as it did before. Whether another planetary interference will sometime bring the principal mass of the November meteors back to the former point of intersection with the earth's orbit is a question for future to decide. It was seen that there may be several parallel streams of the November meteors, and that some of them, like those in August, are distributed entirely around the orbit so that every mid-November we see a few of them. We come now to a very remarkable example of the disintegration of a comet and the formation of a meteor storm. In 1826, Biaia of Jovenstadt, Austria, discovered a comet to which his name was given. The calculation showed that it was an horrible period of about six and a half years belonging to Jupiter's family. On one of its returns in 1846, it astonished its watchers by suddenly splitting into two. The two comets thus formed out of one, separated to a distance about 160,000 miles, and then race side by side, sometimes with a curious ligature connecting them, like Siamese twins, until they disappeared together in interplanetary space. In 1852, they came back, still nearly side by side, but now the distance between them had increased to a million and a quarter miles. After that, at every reoccurrence of the period, astronomers looked for them in vain, until 1872 when an amazing thing happened. On the night of November 28th, when the Earth was crossing the plane of the orbit of the missing comet, a brilliant shower of meteors burst from the northern sky, traveling nearly in track, which the comet had should have pursued. The astronomers were electrified. Clicker-fools and Göttingen telegraphed to pause in a madras. Biela touched Earth, searched near Theta Centauri. Pockets and search in the place indicated, and saw a cometary mass retreating into the southern heavens, where it was soon swallowed from sight. Since then, the Biela meteors have been among the recognized periodic spectacles of the sky, and few if any doubt that they represent a portion of the missing comet whose disintegration began with a separation into two parts in 1846. The comet itself has never since been seen. The first display of these meteors, sometimes called the Andromedes, because they radiate from the constellation Andromeda, was remarkable for its great brilliancy of many fireballs that shot among the shower of smaller sparks, some of which were described as equaling the full moon in size. None of them is known to have reached the Earth, but during the display of the same meteors in 1885, a meteoric mass fell at Marsupil in northern Mexico. It is now in the museum at Vienna, which many have thought may actually be a piece of the original comet Biela. This brings us to the second branch of our subject. More rare than meteors, or falling stars, and more startling, except that they never appear in showers, are the huge balls of fire that occasionally dark through the sky, lighting up the landscapes beneath their glare, leaving trains of sparks behind them, often producing pearls of thunder when they explode, and in many cases, falling upon the Earth and burying themselves from a few inches to several feet in the soil, from which more than once they have been picked up while yet hot and fuming. These balls are sometimes called bull-eyes. They are not really round in shape, although they often look so while traveling through the sky. But their forms are fragmentary and occasionally fantastic. It has been supposed that their origin is different from that of true meteors. It has even been conjectured that they may have originated from the great volcanoes of the moon, or may have been shot out from the sun during some of the tremendous explosions that accompany the formation of eruptive prominences. By the same reasoning, some of them might be supposed to have come from some distant star. Others have conjectured that they are wanderers in space of unknown origin, which the Earth encounters as a journey's on, and Lord Kelvin made a suggestion, which has become classic because of its imaginative reach, that the first germs of life may have been brought to Earth by one of these bodies, a fragment from an exploded world. It is a singular fact that the astronomers and scientific men in general were among the last to admit the possibility of solid masses falling from the sky. The people had believed in the reality of such phenomena from the earliest times, but the savants shook their heads and talked of superstition. This was the less surprising because no scientifically authenticated instance of such an occurrence was known. And the stones popular believed to have fallen from the sky had become the objects of worship or superstitious reverence, a fact not calculated to recommend them to scientific credence. The celebrated Blackstone, suspended in the Kaaba in Mecca, is one of these reputed gifts from heaven. The Palladium of ancient Troy was another, and a stone which fell near Eschentheim in Germany was placed in a church as an object to be religiously venerated. Many legends of falling stones existed in antiquity, some of them curiously transfigured by the imagination, like the Lion of Plasminus, which was said to have had sprung down from the sky upon the isthmus of Cornuth, but near the beginning of the 19th century in 1803, a veritable shower of falling stones occurred at Legalle in Northern France. And this time astronomers took note of the phenomenon and scientifically investigated it. Thousands of the strange projectiles came from the sky on this occasion and were scattered over a wide array of concrete and some buildings were hit. Four years later, another shower of stones occurred at Weston, Connecticut, numbering thousands of individuals. The local arm created in both cases was great, as well it might be for what could be more intimidating than to find the blue vault of Heden, suddenly hurling solid missiles at homes of men. After these occurrences, it was impossible for the most skeptical to doubt any longer and the regular study of error lights or meteorites began. One of the first things recognized was the fact that fireballs are solid meteorites in flight and not gaseous exhalations in the air, as some had assumed. They burn in the air during their flight and sometimes perhaps are entirely consumed before ever reaching the ground. Their velocity before entering the Earth's atmosphere is equal to that of the planets in their orbits from 20 to 30 miles per second. A fact which proves that the Sun is the seat of the central force governing them. Their burning in the air is not difficult to explain. It's the heat of friction which so quickly brings them to incandescence. The calculation shows that a body moving through the air at a velocity about a mile per second will be brought superficially to the temperature of red heat by friction of the atmosphere. If its velocity is 20 miles per second, the temperature will become thousands of degrees. This is the state of affairs with a meteorite rushing into the Earth's atmosphere. Its surface is liquefied within a few seconds after the friction begins to act and the melted and vaporized portion of its mass swept backwards, forming the train of sparks that follows every great fireball. However, there is one phenomenon connected with the trains of meteorites which has never been satisfactory explained. They often persist for long periods of time drifting and turning with the wind but not ceasing to glow with a phosphorescent luminosity. The question is, when comes this light? It must be light without heat since the fine dust or vapor of which the train can only assist would not retain sufficient heat to render it luminous for so long a time. An extremely remarkable incident of this kind occurred on February 22nd, 1909 when an immense fireball that passed over Southern England left a train that remained visible during two hours assuming many curious shapes as it was drifted out by the currents in the air. But notwithstanding, the enormous velocity with which meteorites entered the air, they are soon slowed down to a comparatively moderate speed so that when they disappear, they're usually traveling not faster than a mile a second. The courses of many have been traced by observers situated along their track at various points and thus the knowledge has been maintained of their height above the ground during their flight and the length of their visible courses. They generally appear to within five miles of the ground unless the observer happens to be near the striking point when he may actually witness the fall. Frequently, they burst while hot in the air and their fragments are scattered like shrapnel over the surface of the ground, sometimes covering an area of several square miles but of course not thickly. Different fragments of the same meteorite may reach the ground at points several miles apart. The observed length of their courses in the atmosphere varies from 50 to 500 miles. If they continue to long time in flight after entering the air, even the largest of them would probably be consumed to the last scrap. But their fiery career is so short on account of their great speed that the heat does not have time to penetrate very deeply and some that have been picked up immediately after their fall have been found cold as ice within. Their size after reaching the ground is variable within wide limits. Some are known which weigh several tons but the great majority weigh only a few pounds and many only a few ounces. Meteorites are of two kinds, stony meteorites and iron meteorites. The former outnumber the latter 20 to one but many stone meteorites contain grains of iron. Nickel is commonly found in iron meteorites so that might be said that the redotable alloy nickel steel is of cosmic in dimension. Some 25 chemical elements have been found in meteorites including carbon and the sun metal helium. The presence of the latter is certainly highly suggestive in connection with the question of the origin of meteorites. The iron meteorites besides metallic iron and nickel of which they're almost entirely composed contain hydrogen, helium, carbonic oxide and about the only imaginable way in which these gases could become absorbed in the iron would be through immersion of the latter while in a molten or vaporized state in a hot and dense atmosphere composed of them. A condition which we know to only exist in the envelopes of the sun and the stars. The existence of carbon in the Canyon Diablo iron meteorites is attended by a circumstance of the most singular character a very fairytale science. In some cases, the carbon has become diamond. These meteorite diamonds are very small and they're the less they're true diamonds resembling in many ways, the little black gems pierced by a mason's method with the aid of electric furnace. The fact that they are found embedded in these iron meteorites is another argument in favor of the hypothesis of the solar or stellar origin of the latter. To appreciate that, it is necessary to recall the way in which messiah made his diamonds. It was by a combination of the effects of great heat, great pressure and sudden or rapid superficial cooling on a massive iron containing carbon. When he finally broke open his iron, he found it a pudding stuffed with miniature black diamonds. When a fragment of the Canyon Diablo meteorite iron was polished in Philadelphia over 15 years ago, it cut the emery wheel to pieces. An examination showed that the damage had been affected by microscopic diamonds peppered throughout the mass. How were those diamonds formed? If the sun or Sirius was the laboratory that prepared him, we can get a glimpse at the process of their formation. There's plenty of heat, plenty of pressure and an abundance of vaporized iron in the sun and the stars. When a great solar eruption takes place, the masses of iron which have absorbed carbon may be shot out with a velocity which forbids their return. Plunged into the frightful cold of space, their surfaces are quickly cooled. As Mosian cooled his repaired iron by throwing it into water and thus the requisite stress is set up within. And as the iron solidifies, the included carbon crystallizes into diamonds. Whether this explanation has a germ of truth in it or not, at any rate it is evident that the iron meteorites were not created in the form in which they come to us. They must once have been parts of a measurably more massive bodies than themselves. The fall of meteorites offers an appreciable, though numerically insignificant, peril to the inhabitants of the earth. Historical records show perhaps three or four instances of people being killed by these bodies. But for the protection afforded by the atmosphere, which acts as a very effective shield, the danger would doubtless be very much greater. In the absence of an atmosphere, not only will more meteorites reach the ground, but their striking force would be incomparably greater since, as we have seen, the larger part of their original velocity is destroyed by the resistance of the air. A meteorite weighing many tons and striking the earth with a velocity of 20 to 30 miles per second would probably cause frightful havoc. It is a singular fact that recent investigations seem to have proved that an event of this kind actually happened in North America, perhaps not longer than 1,000 or 2,000 years ago. The scene of the supposed catastrophe is in the northern central Arizona at Coon Butte, where there's a nearly circular crater in the middle of a circular elevation or small mountain. The crater is somewhat over 4,000 feet in diameter, and the surrounding rim formed an upterm strata and ejected rock fragments rises at its highest point, 160 feet above the plane. The crater is about 600 feet in depth, that is, from the rim to the visible floor or bottom of the crater. There is no evidence that volcanic action has ever taken place in the immediate neighborhood of Coon Butte, but the rock in which the crater has been made is composed of horizontal stand zone and limestone strata. Between 300 and 400 million tons of rock fragments have been detached and a large portion hurled by some cause out of the crater. These fragments lie concentrically distributed around the crater, and in large measure form the elevation known as Coon Butte. The region has been famous for nearly 20 years on account of the masses of meteoric iron found scattered about and known as Kenyan Diablo meteorites. It was one of these masses which consists of nickel iron containing a small quantity of platinum, and of which all some 10 tons have been recovered for sale to the various collectors throughout the world that is before mentioned destroyed the grinding tool at Philadelphia through the cutting power of its embedded diamonds. These meteoric irons are scattered about the crater hill in concentric distribution to a maximum distance of about five miles. When the suggestion was first made in 1896 that a monster meteorite might have created by its fall this singular lone crater in stratified rocks, it was greeted with incredulous smiles. But since then, the matter has assumed a different aspect. The standard iron company, formed by measures, Behringer and Tillman, Bennett, Halsinger, have become in 1903 the owner of this freak of nature, sunk shafts and bored holes to a great depth in the interior of the crater and also trench the slopes of the mountain. And the result of their investigations has proved that the meteoric hypothesis of origin is correct. See the papers published in the Proceedings of the Academy of Natural Sciences of Philadelphia, December 1905, wherein it is proved that United States Geological Society was wrong in believing this crater to have been due to steam explosion. Since that date, there's been discovered a great amount of additional confirmatory proof. Material of unmistakably meteoric origin was found by means of the drills, mixed with crushed rock to a depth of 600 to 700 feet below the surface of the crater. And a great deal of it has been found, it mixed with the ejected rock fragments on the outer slopes of the mountain, absolutely proving synchronism between the two events. The formation of this great crater and the falling of the meteoric iron out of the sky, the drill located in the bottom of the crater was sent, in a number of cases, much deeper, over 1,000 feet into unaltered horizontal red sandstone strata. But no meteoric material was found below this depth, 700 feet, or between 11 and 1,200 feet below the surface of the surrounding plain, which has been assumed as being about the limit of penetration. It is not possible to sink a shaft at present, owing to the water straining into the crater, in which forms with the finely pulverized sandstone, with a very troublesome quicksand encountered at about 200 feet below the visible floor of the crater. As soon as this water is removed by pumping, it will be easy to explore the depth secretor by means of shafts and drifts. The rock strata, sandstone and limestone, of which the walls consist, present every appearance of having been violently upturned by a huge body, penetrating the earth like a cannonball. The great aspect of the crater strikingly resembles the impression made by the steel-rejectile shot into an armor plate. Mr. Tillman has estimated that a meteorite of about 500 feet in diameter, and moving with a velocity of about five miles per second, would have made just such a perforation upon striking rocks of the character of those found at this place. There was some fusion of the cooling masses, and the heat produced some steam from the small amount of water in the rocks. As a result, there's been found at a depth a considerable amount of fused quartz, at which innumerable particles are sparks of fused nickel iron, a projectile of that size, penetrating 11 to 1200 feet into the rocky shell of the globe, must have produced a shock which was perceptible 700 miles away. The great velocity ascribed to the supposed meteorite at the moment of striking could be accounted for by the fact that it probably plunged nearly vertically downward, for it formed a circular crater in the rocky crust of the Earth. In that case, it would have been much less retarded by the resistance of the atmosphere. Then our meteorites, which enter the air at a lower angle, and shoot ahead hundreds of miles until friction has nearly destroyed their original motion when they drop upon the Earth. Some meteoric masses of great size, such as Piri's iron meteorite found at Cape York Greenland, and the most equally large mass discovered at Bacerito, Mexico, appear to have penetrated but slightly on striking the Earth. This may be explained by supposing that they are pursed along a long horizontal course through the air before falling. The result would be that the original velocity having been practically destroyed, they would drop to the ground with velocity nearly corresponding to that which gravity went part within a perpendicular distance of their final fall. A 660 pound meteorite, which fell in Nakarai, Hungary, striking at an angle of 27 degrees from the vertical, penetrated the ground to a depth of 11 feet. It has been a remark that the Kumbut meteorite may have fallen not longer ago than a few thousand years. This is based on the fact that the geological indications favor the supposition that the event did not occur more than 5,000 years ago. While on the other hand, the rings of growth in the cedar trees growing on the slopes of the crater show that they have existed there about 700 years. Professor William H. Pickering has recently correlated this with an ancient chronicle which states that in Cairo, Egypt in the year 1029, quote, many stars passed with a great noise, unquote, he remarks that Cairo is about 100 degrees by great circle from Kumbut. So if the meteorite that made the crater was a member of a flock of similar bodies, which encountered the Earth moving in parallel lines, some of them might have traversed the sky tangent to the Earth's surface at Cairo that the spectra will have spoken of in the chronicle was caused by meteorites, he deems exceedingly probable because of what it said it is about, quote, a great noise. Meteorites are the only celestial phenomena attended with perceptible sounds. Professor Pickering conjectures that this supposed flock of great meteorites may have formed the nucleus of a comet which struck the Earth. And he finds confirmation of the idea in the fact that out of the 10 largest meteorites known, no less than seven were found within 900 miles of Kumbut. It would be interesting if we could trace back the history of that comet and find out what malicious planet caught it up in the innocent wanderings and hurled it with so true an aim towards the Earth. This remarkable crater is one of the most interesting places in the world for there is absolutely no record of such a mass, possibly an iron-headed comet from outer space having come into collision with our Earth. The results of the future exploration of the depths of the crater will be awaited with much interest. And chapter 11, read by Greg Bell, Katie, Texas. Chapter 12 of Curiosities of the Sky. This is a LibriVox recording. All LibriVox recordings are in the public domain. For more information or to volunteer, please visit LibriVox.org. Recording by Allison Hester of Athens, Georgia. Curiosities of the Sky by Garrett Service. Chapter 12, The Wrecking of the Moon. There are sympathetic moods under whose influence one gazes with a certain poignant tenderness at the worn face of the moon. That little fossil world, the child of our mother Earth too, bears such terrible scars of its brief, convulsive life that a sense of pity is awakened by the sight. The moon is the wonderland of the telescope, those towering mountains whose proud, aspiring peaks cast silhouettes of shadows that seem drawn with India ink. Those vast plains enchained with gentle winding hills and bordered with giant ranges. Those oval oceans where one looks expectant for the flash of a wind-whipped wave. Those enchanting bays and recesses at the seaward feet of the Alps. Those broad straits passing between guardian heights incomparably mightier than Gibraltar. Those locket-like valleys as secluded among their mountains as the veil of Kashmir. Those colossal craters that make us smile at the pretensions of Vesuvius et Na catupaxi. Those strange white ways which pass with the unconcern of Roman roads across mountain, gorge and valley. All these give the beholder an irresistible impression that it is truly a world into which he is looking, a world akin to ours, and yet no more like our world than Pompeii is like Naples. It's air, it's waters, it's clouds, it's life are gone, and only a skeleton remains, a mute but eloquent witness to a cosmical tragedy without parallel in the range of human knowledge. One cannot but regret that the moon, if it ever was the seat of intelligent life, has not remained so until our time. Think what the consequences would have been if this other world at our very door had been found to be both habitable and inhabited. We talk rather eerily of communicating with Mars by signals, but Mars never approaches nearer than 35 million miles, while the moon, when nearest, is only a little more than 220,000 miles away. Given an effective magnifying power of 5,000 diameters, which will perhaps be possible at the mountain observatories as telescopes improve, and we should be able to bring the moon within an apparent distance of about 40 miles while the corresponding distance from ours would be more than 7,000 miles. But even with existing telescopic powers, we can see details on the moon no larger than some artificial constructions on the earth. St. Peter's at Rome with the Vatican Palace and the Great Piazza, if existing on the moon, would unquestionably be recognizable as something else than a freak of nature. Large cities with their radiating lines of communication would at once betray their real character. Cultivated tracts and the changes produced by the interference of intelligent beings would be clearly recognizable. The electric illumination of a large town at night would probably be markedly visible. Gleams of reflected sunlight would come to us from the surfaces of the lakes and oceans, and a huge liner traversing a lunar sea could probably be followed by its trail of smoke. As to communications by wireless signals, which certain enthusiasts have thought of in connection with Mars, in the case of the moon, they should be a relatively simple matter and the feat might actually be accomplished. Think what a literature would grow up about the moon if it were a living world. Its very differences from the earth would only accentuate its interest for us. Night and day on the moon are each two weeks in length. How interesting it would be to watch the manner in which the Lunarians dealt with such a situation as that. Lunar and terrestrial history would keep step with each other and we would record them both. Truly, one might well wish to have a neighbor world to study. One would feel so much the less alone in space. It is not impossible that the moon did at one time have inhabitants of some kind, but if so, they vanished with the disappearance of its atmosphere and seas or with the advent of its cataclysmic age. At the best, its career as a living world must have been brief. If the water and air were gradually absorbed, as some have conjectured, by its cooling interior rocks, its surface might, nevertheless, have retained them for long ages. But if, as others think, their disappearance was due to the escape of their gaseous molecules and consequence of the inability of the relatively small lunar gravitation to retain them, then the final catastrophe must have been as swift as it was inevitable. Accepting Darwin's hypothesis that the moon was separated from the earth by tidal action, while both were yet plastic or nebulous, we may reasonably conclude that it began its career with a good supply of both water and air, but did not possess sufficient mass to hold them permanently. Yet, it may have retained them long enough for life to develop in many forms upon its surface. In fact, there are so many indications that air and water have not always been lacking to the lunar world that we are driven to invent theories to explain both their former presence and their present absence. But whatever the former condition of the moon may have been, its existing appearance gives it a resistless fascination and it bears so clearly the story of a vast catastrophe sculptured on its rocky face that the thoughtful observer cannot look upon it without a feeling of awe. The gigantic character of the lunar features impresses the beholder, not less, than the universality of the play of destructive forces which they attest. Let us make a few comparisons. TACO, which is a typical example of its kind. In the telescope, TACO appears as a perfect ring surrounding a circular depression in the center of which rises a group of mountains. Its superficial resemblance to some terrestrial volcanic craters is very striking. Vesuvius, seen from a point vertically above, would no doubt look something like that. The resemblance would have been greater when the Monte del Cavallo formed a more complete circuit about the crater comb. But compare the dimensions. The remains of the outer crater ring of Vesuvius are perhaps a half mile in diameter while the active crater itself is only two or 300 feet across at the most. TACO has a diameter of 54 miles. The group of relatively insignificant peaks in the center of the crater floor of TACO is far more massive than the entire mountain that we call Vesuvius. The largest known volcanic crater on the earth, Asosan in Japan, has a diameter of seven miles. It would take 60 craters like Asosan to equal TACO in area. In TACO, though one of the most perfect is by no means the largest crater on the moon. Another called Theophilus has a diameter of 64 miles and is 18,000 feet deep. There are hundreds from 10 to 40 miles in diameter and thousands from one to 10 miles. They are so numerous in many places that they break into one another like the cells of a crushed honeycomb. The lunar craters differ from those of the earth more fundamentally than in the matter of mere size. They are not situated on the tops of mountains. If they were and if all the proportions were the same, a crater like TACO might crown a conical peak 50 or 100 miles high. Instead of being cavities in the summits of mountains, the lunar craters are rather gigantic sinkholes whose bottoms in many cases lie two or three miles below the general surface of the lunar world. Around their rims, the rocks are piled up to a height of from a few hundred to two or 3,000 feet with a comparatively gentle inclination. But on the inner side, they fall away in gigantic broken precipices which make the dizzy cliffs of the Matterhorn seem but lovers leaps. Down they drop, ridge below ridge, crag under crag, tottering wall beneath wall, until in a crater named Newton near the South Lunar Pole, they attain a depth where the rays of the sun never reach. Nothing more frightful than the spectacle which many of these terrible chasms present can be pictured by the imagination. As the lazy lunar day slowly advances, the sunshine unmitigated by clouds or atmospheric veil of any kind creeps across the rims and begins to descend the opposite walls. Presently, it strikes the ragged crest of a ridge which had lain hidden in such darkness as we never know on earth and runs along it like a line of kindling fire. Rocky pinnacles and needles shoot up into the sunlight out of the black depths. Down sinks the line of light mile after mile and continually new precipices and cliffs are brought into view until at last the vast floor is attained and begins to be illuminated. In the meanwhile, the sun's rays darting across the gulf have touched the summits of the central peaks, 20 or 30 miles from the crater's inmost edge and they immediately kindle in blaze like huge stars amid the darkness. So profound are some of these awful craters that days pass before the sun has risen high enough above them to chase the last shadows from their depths. Although several long ranges of mountains resembling those of the earth exist on the moon, the great majority of its elevations assume the crater a form 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 in size on those parts of the moon covering 60% of its visible surface, which are distinctly mountainous in character and which constitute its most brilliant portions. Broadly speaking, the southwestern half of the moon is the most mountainous and broken and the northeastern half the least so. Right down through the crater from pole to pole runs a wonderful line of craters and crater a form valleys of a magnitude stupendous even for the moon. Another similar line follows the western edge. Three or four seas are thrust between these mountainous belts. By the effects of liberation, parts of the opposite hemisphere of the moon which is turned away from the earth are from time to time brought into view and their aspect indicates that the hemisphere resembles in its surface features the one which faces the earth. There are many things about the craters which seem to give some warrant for the hypothesis which has been particularly urged by Mr. G.K. Gilbert that they were formed by the impact of meteors but there are also many things which militate against that idea and upon the whole, the volcanic theory of their origin is to be preferred. The enormous size of the lunar volcanoes is not so difficult to account for when we remember how slight is the force of lunar gravity as compared with that of the earth. With equal size and density, bodies on the moon weigh only one sixth as much as on the earth. Impaled by the same force, a projectile that would go 10 miles on the earth would go 60 miles on the moon. A lunar giant 35 feet tall would weigh no more than an ordinary son of Adam weighs on his greater planet. To shoot a body from the earth so that it would not drop back again, we should have to start with a velocity of seven miles per second. A mile and a half per second would serve on the moon. It is by no means difficult to believe then that a lunar volcano might form a crater ring eight or 10 times broader than the greatest to be found on the earth, especially when we reflect that in addition to the relatively slight force of gravity, the materials of the lunar crust are probably lighter than those of our terrestrial rocks. For similar reasons, it seems not impossible that the theory mentioned in a former chapter that some of the meteorites that have fallen upon the earth originated from lunar volcanoes is well founded. This would apply especially to the stony meteorites for it is hardly to be supposed that the moon, at least in its superficial parts, contains much iron. It is surely a scene most strange that is thus presented to the mind's eye. That little attendant of the earth's, the moon has only one 50th of the volume and one 80th of the mass of the earth firing great stones back at its parent planet. And what can have been the cause of this furious outbreak of volcanic forces on the moon? Evidently it was, but a passing stage in its history. It had enjoyed more quiet times before. As it cooled down from the plastic state in which it parted from the earth, it became encrusted after the normal manner of a planet. And then oceans were formed, its atmosphere being sufficiently dense to prevent the water from evaporating and the would be oceans from disappearing continually in mist. This, if any, must have been the period of life in the lunar world. As we look upon the vestiges of that ancient world buried in the wreck that now covers so much of its surface, it is difficult to restrain the imagination from picturing the scenes which were once presented there. And in such a case, should the imagination be fettered? We give it free reign in terrestrial life and it rewards us with some of our greatest intellectual pleasures. The wonderful landscapes of the moon offer it an ideal field with just enough half-hidden suggestions of facts to stimulate its powers. The great plains of the mayor embryum and the mayor serenitatus, the sea of showers and the sea of serenity bordered in part by lofty mountain ranges, precisely like terrestrial mountains, scalloped along their shores with beautiful bays curving back into the adjoining highlands and united by a great strait passing between the nearly abutting ends of the lunar apennines and the lunar Caucasus, all for the elements of a scene of a world of beauty such as it would be difficult to match upon our planet. Look at the finely modulated bottom of the ancient sea in Mr. Richie's exquisite photograph of the western part of the mayor serenitatus where one seems to see the play of the watery currents heaping the ocean sands and waving lines, making shallows, bars and deeps for the mariner to avoid or seek and affording a playground for the creatures of the main. What geologists would not wish to try his hammer on those rocks with their stony pages of fossilized history? There is in us an instinct which forbids us to think that there was never any life there. If we could visit the moon, there is not among us a person so prosaic and unimaginative that he would not, the very first thing, begin to search for traces of its inhabitants. We would look for them in the deposits on the sea bottoms. We would examine the shores wherever the configuration seemed favorable for harbors in the sites of maritime cities, forgetting that it may be a little ridiculous to ascribe to the ancient Lunarians the same ideas that have governed the development of our race. We would search through the valleys and along the seeming courses of vanished streams. We would explore the mountains, not the terrible craters, but the pinnacle chains that recall our own alps and rockies seeking everywhere some vestige of transforming presence of intelligent life. Perhaps we should find such traces and perhaps with all our searching, we should find nothing to suggest that life had ever existed amid that universal ruin. Look again at the border of the sea of serenity. What a name for such a scene and observe how it has been rent with almost inconceivable violence. The wall of the colossal crater, Poseidonius dropping vertically upon the ancient shore and obliterating it. While its giant neighbor, La Monieur, opens a yawning mouth as if to swallow the sea itself. A scene like this makes one question whether after all, those may not be right who have imagined that the so-called sea bottoms are really vast plains of frozen lava which gushed up in floods so extensive that even the mighty volcanoes were half drowned in the fiery sea. This suggestion becomes even stronger when we turn to another of the photographs of Mr. Richie's wonderful series showing a part of the mayor tranquilitatus, sea of tranquility. Notice how near the center of the picture, the outline of a huge ring with radiating ridges shows through the sea bottom. A fossil volcano submerged in a petrified ocean. This is by no means the only instance in which a buried world shows itself under the great lunar plains. Yet as the newer craters in the sea itself prove, the volcanic activity survived this other catastrophe or broke out again subsequently, bringing more ruin to pile upon ruin. Yet notwithstanding the evidence which we have been considering in support of the hypothesis that the seas are lava floods, Montseur's Lowry and Puyse, the selenographers of the Paris Observatory, are convinced that these great plains bear characteristic marks of the former presence of immense bodies of water. In that case, we should be forced to conclude that the later oceans of the moon lay upon vast sheets of solidified lava and thus the catastrophe of the lunar world assumes a double aspect. The earliest oceans being swallowed up in molten floods issuing from the interior while the lands were reduced to chaos by a universal eruption of tremendous volcanoes. And then a period of comparative quiet followed during which new seas were formed and new life perhaps began to flourish in the lunar world only to end in another cataclysm which finally put a term to the existence of the moon as a life-supporting world. Suppose we examine two more of Mr. Ritchie's illuminating photographs and first the one showing the crater Theophilus and its surroundings. We have spoken of Theophilus before citing the facts that it's 64 miles in diameter and 18,000 feet deep. It will be noticed that it has two brother giants, Cyrus the nearer and Katharina the more distant, but Theophilus is plainly the youngest of the trio. Centuries and perhaps thousands of years must have elapsed between the periods of their upheaval for the two older craters are partly filled with debris while it is manifest at a glance that when the southeastern wall of Theophilus was formed it broke away and destroyed a part of the more ancient ring of Cyrilus. There is no more tremendous scene on the moon than this. Viewed with a powerful telescope, it is absolutely appalling. The next photograph shows, if possible, a still wilder region. It is the part of the moon lying between Takeo and the South Pole. Takeo was seen in the lower left-hand part of the picture. To the right, at the edge of the illuminated portion of the moon are the crater rings, Lungomontanus and Wilhelm I, the former being the larger. Between them are to be seen the ruins of two or three more ancient craters, which together with portions of the walls of Wilhelm I and Lungomontanus have been honeycombed with smaller craters. The vast crater-reformed depression above the center of the picture is Clavius, an unrivaled wonder of lunar scenery. 142 miles in its greatest link while its whole immense floor has sunk two miles below the general surface of the moon outside the ring. The monstrous shadow-filled cavity above Clavius toward the right is Blancanus, whose aspect here gives a good idea of the appearance of these chasms when only their rims are in the sunlight. But observe the indescribable savagery of the entire scene. It looks as though the spirit of destruction had gone mad in this spot. The mighty craters have broken forth one after another, each rending its predecessor. And when their work was finished, a minor but yet tremendous outbreak occurred and the face of the moon was gored and punctured with thousands of smaller craters. These relatively small craters, small however, only in a lunar sense for many of them would appear gigantic on the earth. Recall once more the theory of meteoric impact. It does not seem impossible that some of them may have been formed by such an agency. One would not wish for our planet such a fate as that which has overtaken the moon, but we cannot be absolutely sure that something of the kind may not be in store for it. We really know nothing of the ultimate causes of volcanic activity and some have suggested that the internal energies of the earth may be accumulating instead of dying out and may never yet have exhibited their utmost destructive power. Perhaps the best assurance that we can find that the earth will escape the catastrophe that has overtaken its satellite is to be found in the relatively great force of its gravitation. The moon has been the victim of its weakness, given equal forces and the earth would be the better able to withstand them. It is significant in connection with these considerations that the little planet Mercury, which seems also to have parted with its air and water, shows to the telescope some indications that it is pitted with craters resembling those that have torn to pieces the face of the moon. Upon the whole, after studying the dreadful lunar landscapes, one cannot feel a very enthusiastic sympathy with those who are seeking indications of the continued existence of some kind of life on the moon. Such a world is better without inhabitants. It has met its fate, let it go. Fortunately, it is not so near that it cannot hide its scars and appear beautiful, except when curiosity impels us to look with the penetrating eyes of the astronomer. End of the wrecking of the moon. Chapter 13 of Curiosities of the Sky. This is a LibriVox recording. All LibriVox recordings are in the public domain. For more information or to volunteer, please visit LibriVox.org. This reading by Allison Hester of Athens, Georgia. Curiosities of the Sky by Garrett Service. Chapter 13, The Great Mars Problem. Let any thoughtful person who is acquainted with the general facts of astronomy look up at the heavens some night when they appear in their greatest blender and ask himself what is the strongest impression that they make upon his mind? He may not find it easy to frame an answer, but when he has succeeded, it will probably be to the effect that the stars give him an impression of the universality of intelligence. They make him feel, as the sun and the moon cannot do, that his world is not alone, that all this was not made simply to form a gorgeous canopy over the tents of men. If he is of a devout turn of mind, he thinks as he gazes into those fathomless deeps and among those bewildering hosts of the infinite multitude of created beings that the Almighty has taken under his care. The narrow ideas of the old geocentric theology, which made the earth God's special footstool and man his only rational creature, fall away from him like a veil that has obscured his vision, they are impossible in the presence of what he sees above. Thus, the natural tendency in the light of modern progress is to regard the universe as everywhere filled with life. But science, which is responsible for this broadening of men's thoughts concerning the universality of life, itself proceeds to set limits. Of spiritual existence, it pretends to know nothing, but as to physical beings, it declares that it can only entertain the supposition of their existence where it finds evidence of an environment suited to their needs, and such environment may not everywhere exist. Science, though repelled by the antiquated theological conception of the supreme isolation of man among created beings, regards with complacency, the probability that there are regions in the universe where no organic life exists, stars which shine upon no inhabited worlds, and planets which nourish no animate creatures. The astronomical view of the universe is that it consists of matter in every stage of evolution, some nebulous and chaotic, some just condensing into stars, suns of every magnitude and order, some shaped into finished solar bodies surrounded by dependent planets, some forming stars that perhaps have no planets and will have none, some constituting suns that are already aging and will soon lose their radiant energy and disappear, and some aggregated into masses that long ago became inert, cold and rayless, and that can only be revivified by means about which we can form conjectures, but of which we actually know nothing. As with the stars, so with the planets, which are the satellites of stars, all investigations unite to tell us that the planets are not all in the same state of development, as some are large and some are small, so some are in an evolutionary sense, young and some old, as they depend upon the suns around which they revolve for their light, heat and other forms of radiant energy, so their condition varies with their distance from those suns. Many may never arrive at a state suitable for the maintenance of life upon their surfaces, some which are not at present in such a state may attain it later, and the forms of life themselves may vary with the peculiar environment that different planets afford. Thus, we see that we are not scientifically justified in affirming that life is ubiquitous, although we are thus justified in saying that it must be, in a general sense, universal. We might liken the universe to a garden known to contain every variety of plant. If on entering it, we see no flowers, we examine the species before us and find that they are not of those which bloom at this particular season, or perhaps they are such as never bear flowers. Yet we feel no doubt that we shall find flowers somewhere in the garden because there are species which bloom at this season and the garden contains all varieties. While it is tacitly assumed that there are planets revolving around other stars than the sun, it would be impossible for us to see them with any telescope yet invented, and no instrument now in the possession of astronomers could assure us of their existence. So the only planetary system of which we have visual knowledge is our own. Excluding the asteroids, which could not from any point of view be considered as habitable, we have in the solar system eight planets of various sizes and situated at various distances from the sun. Of these eight, we know that one, the earth, is inhabited. The question then arises, are there any of the others which are inhabited or habitable? Since it is our intention to discuss the habitability of only one of the seven to which the question applies, the rest may be dismissed in a few words. The smallest of them and the nearest to the sun is Mercury, which is regarded as uninhabitable because it has no perceptible supply of water and air and because owing to the extraordinary eccentricity of its orbit, it is subjected to excessive and very rapid alterations in the amount of solar heat and light poured upon its surface, such alterations being inconsistent with the supposition that it can support living beings. Even its average temperature is more than six and a half times that prevailing on the earth. Another circumstance which militates against its habitability is that, according to the results of the best telescopic studies, it always keeps the same face toward the sun so that one half of the planet is perpetually exposed to the fierce solar rays and the other half faces the unmitigated cold of open space. Venus, the next in distance from the sun, is almost the exact twin of the earth and size and many arguments may be urged in favor of its habitability, although it is suspected of possessing the same peculiarity as Mercury and always keeping the same side sunward. Unfortunately, its atmosphere appears to be so dense that no permanent markings on its surface are certainly visible and the question of its actual condition must, for the present, be left in abeyance. Mars, the first planet more distant from the sun than the earth, is the special subject of this chapter and will be described and discussed a few lines further on. Jupiter, Saturn, Uranus and Neptune, the four giant planets, all more distant than Mars and each more distant than the other in the order named, are all regarded as uninhabitable because none of them appears to possess any degree of solidity. They may have solid or liquid nuclei, but exteriorly they seem to be mere balls of cloud. Of course, one can imagine what he pleases about the existence of creatures suited to the physical constitution of such planets as these, but they must be excluded from the category of habitable worlds in the ordinary sense of the term. We go back then to Mars. It will be best to begin with a description of the planet. Mars is 4,230 miles in diameter. Its surface is not much more than one quarter as extensive as that of the earth, 285 thousandths. Its mean distance from the sun is 141,500,000 miles and 48,500,000 miles greater than that of the earth. Since radiant energy varies inversely as the square of distance, Mars receives less than half as much solar light and heat as the earth gets. Mars year, period of revolution around the sun, is 687 days. Its mean density is 71% of the earth and the force of gravity on its surface is 38% of that on the surface of the earth, i.e. a body weighing 100 pounds on the earth would, if transported to Mars, weigh but 38 pounds. The inclination of its equator to the plane of its orbit differs very little from that of the earth's equator and its axial rotation occupies 24 hours, 37 minutes so that the length of day and night and the extent of the seasonal changes on Mars are almost precisely the same as on earth. But owing to the greater length of its year, the seasons of Mars while occurring in the same order are almost twice as long as ours. The surface of the planet is manifestly solid like that of our globe and the telescope reveals many permanent markings on it recalling the appearance of a globe on which geographical features have been represented in reddish and dusky tents. Around the poles are plainly to be seen rounded wide areas which vary in extent with the Martian seasons nearly vanishing in summer and extending widely in winter. The most recent spectroscopic determinations indicate that Mars has an atmosphere perhaps as dense as that to be found on our loftiest mountain peaks and there is a perceptible amount of watery vapor in this atmosphere. The surface of the planet appears to be remarkably level and it has no mountain ranges. No evidences of volcanic action have been discovered on Mars. The dusky and reddish areas were regarded by the early observers as respectively seas and lands but at present it is not believed that there are any bodies of water on the planet. There has never been much doubt expressed that the wide areas about the poles represent snow. It will be seen from this brief description that many remarkable resemblances exist between Mars and the Earth and there is nothing wonderful in the fact that the question of the habitability of the former has become one of extreme and widespread interest giving rise to the most diverse views to many extraordinary speculations and sometimes to regrettably heated controversy. The first champion of the habitability of Mars was Sir William Herschel although even before his time the idea had been suggested. He was convinced by the revelations of his telescopes continually increasing in power that Mars was more like the Earth than any other planet. He could not resist the testimony of the polar snows whose suggestive conduct was in such striking accord with what occurs upon the Earth. Gradually as telescopes improved and observers increased in number the principal features of the planet were disclosed and charted and areography as the geography of Mars was called took its place among the recognized branches of astronomical study. But it was not before 1877 that a fundamentally new discovery in areography gave a truly sensational turn to speculation about life on the red planet. In that year Mars made one of its nearest approaches to the Earth and was so situated in its orbit that it could be observed to a great advantage from the Northern Hemisphere of the Earth. The celebrated Italian astronomer Shia Parelli took advantage of this opportunity to make a trigonometrical survey of the surface of Mars as coolly and confidently as if he were not taking his sights across a 35 million mile gulf of empty space. And in the course of this survey he was astonished to perceive that the reddish areas then called continents were crossed in many directions by narrow dusky lines to which he gave the suggestive name of canals. Thus a kind of firebrand was cast into the field of astronomical speculation which has ever since produced disputes that have sometimes approached the violence of political faction. At first the accuracy of Shia Parelli's observations was contested. It required a powerful telescope and the most excellent seeing to render the enigmatic lines visible at all and many searchers were unable to detect them. But Shia Parelli continued his studies in the serene sky of Italy and produced charts of the gridiron face of Mars containing so much astonishing detail that one had either to reject them totally or to confess that Shia Parelli was right. As subsequent favorable oppositions of Mars occurred other observers began to see the canals and to confirm the substantial accuracy of the Italian astronomer's work. And finally few were found who would venture to affirm that the canals did not exist whatever their meaning might be. When Shia Parelli began his observations it was generally believed as we have said that the dusky areas on Mars were seas and since Shia Parelli thought the canals and variably began and ended at the shores of the seas the appropriateness of the title given to the lines seemed apparent. Their artificial character was immediately assumed by many because they were too straight and too suggestively geometrical in their arrangement to permit the conclusion that they were natural water courses. A most surprising circumstance noted by Shia Parelli was that the canals made their appearance after the melting of the polar snow in the corresponding hemisphere had begun. And that they grew darker, longer and more numerous in proportion as the polar liquidation proceeded. Another very puzzling observation was that many of them became double as the season advanced close beside an already existing canal and in perfect parallelism with it. Another would gradually make its appearance that these phenomena ever existed and were not illusions were proved by later observations and today they are seen whenever Mars is favorably situated for observation. In the closing decade of the 19th century Mr. Percival Lowell took up the work where Shia Parelli had virtually dropped it and soon added a great number of canals to those previously known so that in his charts the surface of the wonderful little planet appears covered with a spider's web the dusky lines crisscrossing in every direction with conspicuous knots where every number of them come together. Mr. Lowell has demonstrated that the areas originally called seas and thus named on the earlier charts are not bodies of water, whatever else they may be. He has also found that the mysterious lines do not as Shia Parelli supposed begin and end at the edges of the dusky regions but often continue on across them reaching in some cases far up into the polar regions. But Shia Parelli was right in his observation that the appearance of the canals is synchronous with the gradual disappearance of the polar snows and this fact has become the basis of the most extraordinary theory that the subject of life in other worlds has ever given birth to. Now, the effect of such discoveries as we have related depends upon the type of mind to whose attention they are called. Many are content to accept them as strange and inexplicable at present and to wait for further light upon them. Others insist upon an immediate inquiry concerning their probable nature and meaning. Such an inquiry can only be based upon inference proceeding from analogy. Mars, say Mr. Lowell and those who are of his opinion is manifestly a solidly encrusted planet like the Earth. It has an atmosphere, though one of great rarity. It has water vapor as the snows in themselves prove. It has the alternation of day and night and a succession of seasons closely resembling those of the Earth. Its surface is suggestively divided into regions of contrasting colors and appearance and upon that surface, we see an immense number of lines geometrically arranged with a system of symmetrical intersections where the lines expand into circular and oval areas and all connected with the annual melting of the polar snows in a way which irresistibly suggests the interference of intelligence directed to a definite end. Why, with so many concurrent circumstances to support the hypothesis, should we not regard Mars as an inhabited globe? But the differences between Mars and the Earth are in many ways as striking as the resemblances. Mars is relatively small. It gets less than half as much light and heat as we receive. Its atmosphere is so rare that it would be distressing to us even if we could survive in it at all. It has no lakes, rivers, or seas. Its surface is an endless prairie and its canals are phenomena utterly unlike anything on the Earth. Yet it is precisely upon these divergences between the Earth and Mars, this repudiation of terrestrial standards that the theory of life on Mars, for which Mr. Lowell is mainly responsible, is based. Because Mars is smaller than the Earth, we are told it must necessarily be more advanced in planetary evolution, the underlying cause of which is the gradual cooling and contraction of the planet's mass. Mars has parted with its internal heat more rapidly than the Earth. Consequently, its waters and its atmosphere have been mostly withdrawn by chemical combinations. But enough of both yet remain to render life still possible on its surface. As the globe of Mars is evolutionally older than that of the Earth, so its forms of organic life may be proportionally further advanced and its inhabitants may have attained a degree of cultivated intelligence much superior to what at present exists upon the Earth. Understanding the nature and the causes of the desiccation of their planet and possessing engineering, science, and capabilities far in advance of ours, they may be conceived to have grappled with the stupendous problem of keeping their world in a habitable condition as long as possible. Supposing them to have become accustomed to live in their rare filled atmosphere. A thing not inconceivable since men can live for a time at least in air hardly less rare. The most pressing problem for them is that of a water supply without which plant life cannot exist while animal life in turn depends for its existence upon vegetation. The only direction in which they can seek water is that of the polar regions where it is alternately condensed into snow and released in the liquid form by the effect of the seasonal changes. It is then to the annual melting of the polar snow fields that the Martian engineers are supposed to have recourse in supplying their needs of the planet and thus providing the means of prolonging their own existence. It is imagined that they have for this purpose constructed a stupendous system of irrigation extending over the temperate and equatorial regions of the planet. The canals represent the lines of irrigation but the narrow streaks that we see are not the canals themselves but the irrigated bands covered by them. Their dark hue and their gradual appearance after the polar melting has begun are due to the growth of vegetation stimulated by the water. The rounded areas are visible where several canals meet and cross are called by Mr. Lowell Oasis. These are supposed to be the principal centers of population and industry. It must be confessed that some of them with their complicated systems of radiating lines appear to answer very well to such a theory. No attempt to explain them by analogy with natural phenomena on the earth has proved successful. But a great difficulty yet remains how to explain the seemingly miraculous powers of the supposed engineers. Here recourse is had once more to the relative smallness of the planet. We have remarked that the force of gravity on Mars is only 38% of that on the earth. A steam shovel driven by a certain horsepower would be nearly three times as effective there as here. A man of our stature on Mars would find his effective strength increased in the same proportion. But just because of the slight force of gravity there a Martian might attain to the traditional stature of Goliath without finding his own weight and encumbrance to his activity. While at the same time his huge muscles would come into unimpeded play enabling him single handed to perform labors that would be impossible to a whole gang of terrestrial workmen. The effective powers of huge machines would be increased in the same way. And to all this must be added the fact that the mean density of the materials of which Mars is composed is much less than that of the constituents of the earth. Combining all these considerations it becomes much less difficult to conceive that public works might successfully be undertaken on Mars which would be hopelessly beyond the limits of human accomplishment. Certain other difficulties have also to be met as for instance the relative coldness of the climate of Mars as its distance gets considerably less than half as much light and heat as we receive. In addition to this the rarity of its atmosphere would naturally be expected to decrease the effective temperature at the planet's surface since an atmosphere acts somewhat like the glass cover of a hot house in retaining the solar heat which has penetrated it. It has been calculated that unless there are mitigating circumstances of which we know nothing the average temperature at the surface of Mars must be far below the freezing point of water. To this it is replied that the possible mitigating circumstances spoken of evidently exist in fact because we can see that the water vapor condenses into snow around the poles in winter but melts again when summer comes. The mitigating agent may be supposed to exist in the atmosphere where the presence of certain gases would completely alter the temperature gradients. It might also be objected that it is inconceivable that the Martian engineers however great may be their physical powers and however gigantic the mechanical energies under their control could force water in large quantities from the poles to the equator. This is an achievement that measures up to the cosmical standard. It is admitted by the champions of the theory that the difficulty is a formidable one but they call attention to the singular fact that on Mars there can be found no chains of mountains and it is even doubtful if ranges of hills exist there. The entire surface of the planet appears to be almost as smooth as a billiard ball and even the broad regions which were once supposed to be seas apparently lie at practically the same level as the other parts since the canals in many cases run uninterruptedly across them. Lowell's idea is that these somber areas may be expanses of vegetation covering the ground of a more or less marshy character. For while the largest of them appear to be permanent there are some which vary coincidentally with the variations of the canals. As to the kind of machinery employed to force the water from the poles it has been conjectured that it may have taken the form of a gigantic system of pumps and conduits and since the Martians are assumed to be so far in advance of us and their mastery of scientific principles the hypothesis will at least not be harmed by supposing that they have learned to harness forces of nature whose very existence in manageable form is yet unrecognized on the earth. If we wish to let the imagination loose we may conjecture that they have conquered the secret of those intra-atomic forces whose resistless energy is beginning to become evident to us but the possibility of whose utilization remains a dream the fulfillment of which nobody dares to predict. Such in very brief form is the celebrated theory of Mars as an inhabited world. It certainly captivates the imagination and if we believe it to represent the fact we cannot but watch with the deepest sympathy this gallant struggle of an intellectual race to preserve its planet from the effects of advancing age and death. We may indeed wonder whether our own humanity confronted by such a calamity could be counted on to meet the emergency with equal stoutness of heart and inexhaustableness of resource. Up to the present time we certainly have shown no capacity to confront nature toe to toe and to seize her by the shoulders and to turn her round when she refuses to go our way. If we could get into wireless telephonic communication with the Martians we might learn from their own lips the secret of their more than Roman recovery. End of chapter 13.