CHAPTER VIII.

LITTLE SERVANTS.

If you walk out any night after dark, and watch the bright stars shining in a clear sky--shining as they have done for ages past--you will probably see, now and then, a bright point of light suddenly appear, dart along a little distance, and as suddenly vanish. That which you have seen was not the beginning of a story, but in ninety-nine cases out of a hundred it was the end of a story. The little shooting-star was in existence long before you saw him, whirling through space with millions of little companions. But he has left them all, and dropped to earth. He is a shooting-star no longer.

If such a journey to the moon as the one described two chapters back were indeed possible, the voyage aloft would hardly be so easily and safely performed as is there taken for granted. Putting aside the thought of other difficulties, such as lack of conveyance and lack of air, there would be the danger of passing through a very considerable storm of missiles--a kind of “celestial cannonade”--which, to say the least, would prove very far from agreeable.

These “starlets” and “meteor planets,” as they have been called, are not visible in a normal condition, because of their minuteness. But on entering our atmosphere they are rendered luminous, owing to the heat evolved by the sudden and violent compression of the air in front of the moving body. According to this view, shooting-stars, which simply dart across the heavens, may be regarded as coming within the limits of the atmosphere, and carried out of it again, by their immense velocity, passing on in space. Meteoric showers may result from an encounter with a group of these bodies, while aërolites are those which come so far within the sphere of the earth’s attraction as to fall to its surface. More than two thousand years ago the Greeks venerated a famous stone which fell from the heavens on the river Ægos.

[Illustration: METEOR EMERGING FROM BEHIND A CLOUD (NOV. 23, 1877).]

It will scarcely be believed what numbers of these shooting-stars or meteorites constantly fall to the earth. As she travels on her orbit, hurrying along at the rate of nineteen miles each second, she meets them by tens of thousands. They too, like the earth, are journeying round the great center of our family. But they are so tiny, and the earth by comparison is so immense, that her strong attraction overpowers one after another, drags it from its pathway, and draws it to herself.

And then it falls, flashing like a bright star across the sky, and the little meteorite has come to his end. His myriads of companions, hastening still along their heavenly track--for the meteorites seem to travel commonly in vast flocks or companies--might, had they sense, mourn in vain for the lost members of their family.

Any one taking the trouble to watch carefully some portion of the sky after dark, may expect to see each hour about four to eight of these shooting-stars--except in the months of August and November, when the number is much larger. About six in an hour does not sound a great deal. But that merely means that there have been six in one direction, and near enough for you to see. Somebody else, watching, may have seen six in another direction; and somebody else, a few miles away, may have seen six more. It is calculated that, in the course of every twenty-four hours, about four hundred millions of meteorites fall to earth, including those visible only through telescopes.

This is rather startling. What if you or I should some day be struck by one of these solid, hard little bodies, darting as they do towards earth with speed swifter than that of a cannon-ball? True, they are not really stars, neither are they really planets. But they are, to say the least, often much larger than a cannon-ball, and a cannon-ball can destroy life.

Four hundred millions every twenty-four hours! Does it not seem singular that we do not see them constantly dropping to the ground? The truth is, we _should_ see them, and feel them too, and dire would be the danger to human life, but for a certain protecting something folded round this earth of ours to ward off the peril. That “something” is the earth’s atmosphere. But for the thick, soft, strong, elastic air through which the meteorites have to pass, they would fall with fearful violence, often doing terrible mischief. As it is, we are guarded. The shooting-star, drawn by the earth’s attraction, drops into her atmosphere, darting with tremendous speed. In consequence of this speed and the resistance of the air, it catches fire. That is when we first see it. The meteorites are believed to appear at a height of about seventy miles, and to disappear at a height of about fifty miles. So that, in one instant’s flash, the shooting-star has traveled some twenty miles toward us. Then the light goes out. The little meteorite is burnt. It falls to earth still; but only as fine dust, sinking harmlessly downward.

The meteorites do not always vanish so quickly. Now and then a larger one--too large to be rapidly burnt--does actually reach the ground. If any man were struck by such a stone he would undoubtedly be killed.

When meteorites thus fall to earth they are usually called _aërolites_. Some are found no bigger than a man’s fist, while others much exceed this size. There is one, kept carefully in the British Museum, which weighs three tons and a half; and we hear of another, lying in South America, between seven and eight feet in length. Such a sky-visitant would be very unwelcome in any of our towns.

We must remember that, whatever size an aërolite may be when it reaches the earth, it must have been far greater when journeying round the sun, since a good part of it has been burnt away during its rush downward through the earth’s atmosphere.

Meteors, or bolides, or fireballs, are of much the same nature as meteorites; but they are larger, longer to be seen, and slower in movement. Also, it is not uncommon for them to burst with a loud explosion. Early in the present century such a meteor visited Normandy. It exploded with a noise like the roll of musketry, scattering thousands of hot stones over a distance of several miles. A great number of them were collected, still smoking. The largest of these stones weighed no less than twenty pounds. Happily no one seems to have been injured. Other such falls have taken place from time to time. Sometimes bright, slowly-moving meteors have been seen, looking as large as the moon.

A remarkable fireball appeared in England on November 6, 1869. This fireball was extensively seen from different parts of the island, and by combining and comparing these observations, we obtain accurate information as to the height of the object and the velocity with which it traveled. It appears that this meteor commenced to be visible at a point ninety miles above Frome, in Somersetshire, and that it disappeared at a point twenty-seven miles over the sea, near St. Ives, in Cornwall. The whole length of its course was about 170 miles, which was performed in a period of five seconds, thus giving an average velocity of thirty-four miles a second. A remarkable feature in the appearance which this fireball presented was the long, persistent streak of luminous cloud, about fifty miles long and four miles wide, which remained in sight for fully fifty minutes. We have in this example an illustration of the chief features of the phenomena of a shooting-star presented on a very grand scale. It is, however, to be observed that the persistent luminous streak is not a universal, nor, indeed, a very common characteristic of a shooting-star.

If we may liken comets to the _fishes_ of the Solar System--and in their number, their speed, their varying sizes, their diverse motions, they may be fairly so likened--we may perhaps speak of the meteorites as the _animalcula_ of the Solar System. For, in comparison with the planets, they are, in the matter of size, as the animalcula of our ponds in comparison with human beings. In point of numbers they are countless.

Take a single drop of water from some long-stagnant pond, and place it under a powerful microscope. You will find it to be full of life, teeming with tiny animals, darting briskly to and fro. The drop of water is in itself a world of living creatures, though the naked eye of man could never discover their existence. So with the meteorites. There is good reason to believe that the Solar System fairly teems with them. We talk of “wide gaps of empty space,” between the planets; but how do we know that there is any such thing as empty space to be found throughout all the sun’s domain?

Not only are the meteorites themselves countless, a matter easily realized, but the families or systems of meteorites appear to be countless also. They, like the systems of Jupiter and Saturn, are each a family within a family--a part of the Solar System, and yet a complete system by themselves. Each circles round the sun, and each consists of millions of tiny meteorites. When I say “tiny,” I mean it of course only by comparison with other heavenly bodies. Many among them may possibly be hundreds of feet and even more in diameter, but the greater proportion appear to be much smaller. It is not impossible that multitudes beyond imagination exist, so small in size that it is impossible we should ever see them, since their dying flash in the upper regions of our atmosphere would be too faint to reach our sight.

The earth, traveling on her narrow orbit round the sun, crosses the track of about one hundred of these systems, or rings. Sometimes she merely touches the edge of a ring, and sometimes she goes into the very thick of a dense shower of meteorites. Twice every year, for instance, on the 10th of August and the 11th of November, the earth passes through such a ring, and very many falling stars may be seen on those nights. Numbers of little meteorites, dragged from their orbits and entangled in the earth’s atmosphere, like a fly caught in a spider’s web, give their dying flash, and vanish. It used to be supposed that the August and November meteorites belonged to one single system; but now they are believed to be two entirely distinct systems.

[Illustration: THE GREAT SHOWER OF SHOOTING-STARS, NOVEMBER 27, 1872.]

The comet discovered on February 27, 1827, by Biela, and ten days later at Marseilles by Gambart, who recognized that it was the same as that of 1772 and 1805, returned six and a half years later, in 1832. In fact it crossed, as we have seen, the plane of the terrestrial orbit at the respectable distance of fifty millions of miles from the earth; but if there was any danger in this meeting, it was rather for it than for us; for it was certainly strongly disturbed in its course. It returned in 1839, but under conditions too unfavorable to enable it to be observed--in the month of July, in the long days, and too near the sun. It was seen again in 1845, on November 25th, near the place assigned to it by calculation, and its course was duly followed. Everything went on to the general satisfaction, when--unexpected spectacle!--on January 13, 1846, _the comet split into two_! What had passed in its bosom? Why this separation? What was the cause of such a celestial cataclysm? We do not know; but the fact is, that instead of one comet, two were henceforth seen, which continued to move in space like two twin-sisters--two veritable comets, each having its nucleus, its head, its coma, and its tail, slowly separating from each other. On February 10th there was already a hundred and fifty thousand miles of space between the two. They would seem, however, to have parted with regret, and during several days a sort of bridge was seen thrown from one to the other. The cometary couple, departing from the earth, soon disappeared in the infinite night.

They returned within view of the earth in the month of September, 1852. On the 26th of this month the twins reappeared, but much farther apart, separated by an interval of twelve hundred and fifty thousand miles.

But this is not the strangest peculiarity which this curious body presented to the attention of astronomers. The catastrophe which was observed in 1846 was only a presage of the fate which awaited it; for now its existence is merely imagined, the truth being that _this comet is lost_. Since 1852 all attempts to find it again have been unavailing.

To be lost is interesting, especially for a comet. But this, doubtless, was not enough; for it reserved for us a still more complete surprise. Its orbit intersects the terrestrial orbit at a point which the earth passes on November 27th. Well, nothing more was thought about it--it was given up as hopeless, when, on the evening of November 27, 1872, there fell from the sky a veritable _rain of shooting stars_. The expression is not exaggerated. They fell in great flakes. Lines of fire glided almost vertically in swarms and showers--here, with dazzling globes of light; there, with silent explosions, recalling to mind those of rockets; and this rain lasted from seven o’clock in the evening till one o’clock next morning, the maximum being attained about nine o’clock. At the observatory of the Roman College, 13,892 were counted; at Montcalieri, 33,400; in England a single observer counted 10,579, etc. The total number seen was estimated at _a hundred and sixty thousand_. They all came from the same point of the sky, situated near the beautiful star Gamma of Andromeda.

On that evening I happened to be at Rome, in the quarter of the Villa Medicis, and was favored with a balcony looking towards the south. This wonderful rain of stars fell almost before my eyes, so to say, and I shall never cease regretting not having seen it. Convalescent from a fever caught in the Pontine Marshes, I was obliged to go into the house immediately after the setting of the sun, which on that evening appeared from the top of the Coliseum to sleep in a bed of purple and gold. My readers will understand what disappointment I felt next morning when, on going to the observatory, Father Secchi informed me of that event! How had he observed it himself? By the most fortunate chance: A friend of his, seeing the stars fall, went to him to ask an explanation of such a phenomenon. It was then half-past seven. The spectacle had commenced; but it was far from being finished, and the illustrious astronomer was enabled to view the marvelous shower of nearly _fourteen thousand_ meteors.

This event made a considerable stir in Rome, and the pope himself did not remain indifferent; for, some days afterwards, having had the honor of being received at the Vatican, the first words that Pius IX addressed to me were these: “Have you seen the shower of Danaë?” I had admired, some days before in Rome, some admirable “Danaës,” painted by the great masters of the Italian school in a manner which left nothing to be desired; but I had not had the privilege of finding myself under the cupola of the sky during this new celestial shower, more beautiful even than that of Jupiter.

What was this shower of stars? Evidently--and this is not doubtful--the encounter with the earth of myriads of small particles of matter moving in space along the orbit of Biela’s comet. The comet itself, if it still existed, would have passed twelve weeks before. It was not, then, to speak correctly, the comet itself which we encountered, but perhaps a fraction of its decomposed parts, which, since the breaking-up of the comet in 1846, would be dispersed along its orbit behind the head of the comet.[1]

[1] No doubt can remain of the identity of this swarm of shooting-stars with the comet of Biela. On November 27, 1885, the same encounter occurred. A magnificent shower of stars was observed all over Europe just at the moment when the earth crossed the comet’s orbit.

Once in every thirty-three years we have a grand display of meteorites in November; tens of thousands being visible in one single night. The meteorites in that ring have their “year” of thirty-three earthly years, and once in the course of that long year our earth’s orbit carries her deep into their midst. In this single November ring there are myriads upon myriads of meteorites, spreading through millions of miles of space.

Yet this system is but one among many. There is no reason whatever to suppose that the streams of meteorites cluster more thickly about the orbit of the earth, than in other parts of the Solar System. No doubt the rest of the planets come across quite as many. Indeed, the wonderful rings of Saturn are probably formed entirely of meteorites--millions upon millions of them whirling round the planet in a regular orbit-belt, lit up by the rays of the sun. Also it is believed that the meteorite families cluster more and more closely in the near neighborhood of the sun, rushing wildly round him, and falling by millions into the ocean of flame upon his surface. It has even been guessed that they may serve in part as fuel to keep up his mighty furnace heat.

There is a curious cone-shaped light seen sometimes in the west after sunset. It is called the “Zodiacal Light,” and men have often been much puzzled to account for it. The shining is soft and dim, only to be seen when the sky is clear, and only to be seen in the neighborhood of the sun. This, too, _may_ be caused by reflected light from countless myriads of meteorites gathering thickly round the sun.