CHAPTER X
MORE WORLDS THAN TWO.
It was now so late in the day that further conversation was postponed,and after a plain but exceedingly enjoyable supper we were shownto luxurious rooms, where we spent our first night in Mars in greatcomfort.
In the morning Thorwald told us we would reach our port in a few hours,and so we sat down as early as we could after breakfast for a shorttalk.
The doctor furnished the text by opening the conversation with thisremark:
"It is wonderful to think we should find on this planet a race of peopleso advanced, when so little thought is given, on the earth, to the ideaof life in other worlds."
"What has been the general opinion among you on that subject?" askedThorwald.
"The subject has not had standing enough to call forth much opinion,"the doctor answered. "There is an almost universal indifference inregard to the matter. I think the common notion is that the earth isabout all there is in the universe worth considering."
"But what are your own views, Doctor?"
"I have been one of those," he replied, "who believed the notion oflife outside the earth to be a beautiful theory without one shred ofscientific basis. We knew the earth was inhabited and the moon was not,and there we stopped. We did not know, and thought we never could know,anything that could be called evidence pointing to the existence oflife in the other planets or elsewhere, and we held that there was noadvantage in speculation. We thought it unwise to spend much time orthought on a subject about which we could know nothing. On coming hereand finding you I have learned that Mars is inhabited, but I do not knowany more about the other planets or stars."
"Does not the mere knowledge that there are two life-bearing bodies leadyou to believe that there are more, among the vast numbers of worldswhich you have not visited?"
"I don't see why it should. How can we believe anything withoutevidence? No one has ever come to us from those distant globes, and theyare too far away for us to see what is taking place on their surface."
"It seems strange, Doctor, to hear you reason in that way, but I supposesome of our race were just as narrow, if you will pardon me for usingthat word, as you are, before our wonderful successes in astronomy. Ibelieve you have not properly considered the subject, for it seems to meyou had knowledge enough, before you left the earth, to justify you inholding to a strong probability of life beyond your own globe.
"Let us see what some of that knowledge is. You know, to begin with,that one world is inhabited. Then if you should find other bodies aslarge as the earth and bearing any resemblance to it, there would be noimprobability in the thought that they or some of them were filled withlife. The improbability is certainly taken away by the knowledge thatone such body, the earth, is inhabited.
"You start, then, without prejudice, on a voyage of discovery, aided byyour telescope and your reasoning faculties.
"First you find, within distances that you can easily measure, a smallgroup of dark bodies, which you have called planets, all apparentlygoverned by a common law, in obedience to which they are circling arounda large body of quite different character, which gives them light andheat. Of these dark bodies, which shine in the sky only by reflectedlight, the earth is one, and, you are surprised to find, not the mostimportant one, judging from all you can discover. Some of the others aremuch larger and are attended by more satellites. In fact, the earth isindistinguishable in this little group. While it is not the largest,neither is it the smallest. It is not the farthest from the sun nor thenearest to it. It is merely one among the number. And how much alikethe members of this family are. Your telescopes do not point out anymaterial differences, although each has its individual characteristics.Let us enumerate some of the many points of resemblance. They all turnon themselves as well as revolve around the sun. All see the nightfollow the day, and in most of them there must occur the regularsuccession of seasons. To each one the sun is the source of light andheat, many of them have moons, and all can see the stars. Nor doesthe resemblance stop here. For you have discovered that one has anatmosphere, another is surrounded with clouds, while on the surface ofour own globe you see the polar snows increase in winter and melt awayin summer. Is it not probable that if you could get nearer to theseglobes you would find still closer resemblances? And if they are likethe earth in so many ways, is it at all unlikely that they may, at someperiod of their existence, be the abode of intelligent life? For whatother purpose were they made, Doctor?"
"They make very pretty objects for us to look at," replied my companion.
"Yes, those that can be seen," said Thorwald; "but is that all? Werethose great worlds, some of them hundreds of times larger than your ownglobe, created merely to add a little variety to your sky, and to giveyou the pleasant task of watching their movements under the pretty titleof morning and evening star?"
"Speaking from the knowledge I had when I left the earth," the doctoranswered, "I can say I never heard that they were put to any other use.No one ever came down to us from any of them to tell us they wereinhabited."
"And do you think," asked Thorwald, "that the myriads of stars were alsomade simply to delight the eye of man?"
"How do I know that they were not?" the doctor asked in reply.
"Because of the absolute unreasonableness of the thought, if for noother reason," answered Thorwald. "But now let me recall to your mindmore of the knowledge possessed by the inhabitants of the earth. Ithink I know about what that knowledge is, from my acquaintance withthe present state of your development. Astronomy has been our masterscience, and I can remember fairly well the extent of our knowledgewhen we had reached your stage. If I should fall into the error ofattributing to you more than you have already discovered you can easilycorrect me.
"If, now, you leave the little group of dark bodies which are so likethe earth, and go out still further into space, what do you find?At distances so great that only the speed of light can be used as ameasuring line, you discover vast numbers of self-luminous bodies, whichyou call stars. Your natural eye can tell but a small fraction oftheir number. For example, look at the constellation you have named thePleiades and you see six or seven stars. View it through a three-inchtelescope and you can count perhaps three hundred. Now attach aphotographic plate to the telescope, and with an exposure of four hoursthe light coming from that small patch of sky falls upon the sensitivefilm with a cumulative effect until you have a picture of more than twothousand three hundred stars."
"Yes," broke in the doctor, "you are gauging correctly the state of ourknowledge. Our largest telescopes reveal in the entire sky, it is said,one hundred million stars."
"Then," answered Thorwald, "if the glories of the heavens were mademerely to delight the eye of man, why was not the eye created ofsufficient power to behold them? As it is, only a small proportion ofthe stars can be seen without the aid of instruments too costly and toodelicate for general use.
"But have you the means of establishing any likeness between theearth and those distant bodies? You have discovered that the law ofgravitation is universal and that the motions of the stars resemblethose of the solar system. Have you made any discoveries tending toprove the existence of other systems like our own?"
"Yes," replied the doctor, "our recent investigations of the periods ofsome of the variable stars show irregularities in brightness, period,and proper motion. A close study of these irregularities has convincedsome of our astronomers that there are invisible bodies near them,evidently planets circling around a central sun. The theory is that thedark bodies cause slight perturbations in the star, which account forthe irregularities in period, motion, etc. So Neptune was discoveredby the effect it had upon the observed movements of Uranus. This is thefirst evidence we have had tending to prove that there are other groupsof worlds like ours, and it is considered quite significant."
"I can readily believe it," said Thorwald, "and I know how helpful everybit of evidence is, in your search for knowledge. But if I mistake notyou have the ai
d of another instrument, which is destined to play animportant part in your future studies. You get much nearer those distantorbs when a spectroscope is placed at the end of the telescope, andthe ray of light coming from sun and star is widened out into a bandof color, which tells a marvelous story. That light, that has been foryears, and perhaps for centuries, on its way to you, now discloses thevery nature of the substances which compose those fiery globes. And whatare those substances? It must have been a startling truth to the manwho first read from the spectrum of the star he was studying, that itcontained matter with which he was familiar, materials of which theearth itself is made. By this science you have learned beyond doubt thatmany of the commonest elements of the earth's crust exist also in otherworlds, and, what is of great significance, that the materials mostclosely connected with living organisms on the earth, such as hydrogen,sodium, magnesium, and iron, are the very ones which are found mostwidely diffused among the stars. I think I am not wrong in assuming thatyou are somewhat acquainted with the spectroscope and have made thesediscoveries."
"You are quite right," said the doctor. "This branch of scientificinvestigation has already been carried so far with us, and the resultsof the experiments are so constant and uniform, that when it isasserted, for example, that such and such a metal is present in a stateof vapor in the sun's atmosphere, it is estimated that the chances infavor of the correctness of the assertion are as 300,000,000 to 1."
"You are helping my argument, Doctor," resumed Thorwald. "But now letme call your attention to another field of inquiry, in our search forevidence to establish a likeness between the earth and the other partsof the universe. You told me, a while ago, that you have the fall ofmeteorites on your globe. Have you considered the striking evidence theybring you? Let us imagine we have a meteoric fragment here. Take it inyour hand and think of it a moment. You have few things on your earth asinteresting as this piece of metallic stone. What a world of questionsit starts! What is its composition? Whence comes it? Once it was inexistence, but not here. Where, then, was its home? Out, out in thedepths of space, where burning suns roll and comets have their dwellingplace. The stars have fallen indeed, and here is one of the pieces.Before it came to us as a messenger from the sky did it have anindependent existence, or is it a fragment of a shattered world? Howlong has it been whirling in its unknown orbit, and what story has itfor us from its distant birthplace? If we can discover whence meteoritescome, and of what they are composed, I think you will agree with me thatthey furnish valuable testimony in our inquiry. You have no doubt hadmany theories as to their origin."
I was just about to make answer to this implied question, when Thorwaldrose and eagerly scanned the horizon. After a moment he exclaimed:
"We shall have to break off our conversation for a time, as we arenearing our port. I knew by other means that land must soon appear, andnow I can see it."