A Thing of Eyes, that all survey, ...
A Thought Unseen, yet seeing all!”[[96]]
He stands in the starry solitude, waving his wand, and lo! he peoples each glistening speck with intellectual existence, with the highest order of intelligence, as in the case of that little star, the sun, which he has quitted. Now as to these same FIXED STARS, we can easily guess the steps of Sir David’s brief and satisfactory argument. If the stars be suns, they are inhabited like our sun; and if they be suns, each has its planets, like our sun; and if they have planets, they are inhabited like our planets; and if they have satellites like some of ours, they are also inhabited. But the stars are suns, and they all have planets, and at least some of these planets, satellites; therefore, all the fixed stars, with their respective planetary systems, are inhabited (Q. E. D.) Here are Sir David’s words:—“We are compelled to draw the conclusion that wherever there is a sun, there must be a planetary system; and wherever there is a planetary system, there must be Life and Intelligence.”[[97]] This is the way in which, it seems, we worms of the earth feel ourselves at liberty to deal with our Almighty Creator: dogmatically insisting that every scene of existence in which He may have displayed His omnipotence, is but a repetition of that particular one in which we have our allotted place! As if He had but one pattern for Universal Creation! Only one scheme for peopling and dealing with infinitude! O, that the clay should think thus of Him that fashioneth it![[98]] Forgetting, in an exulting moment of blindness and presumption, His own awful words, My thoughts are not as your thoughts, neither are your ways my ways. For as the Heavens are higher than the Earth, so are my ways higher than your ways, and my thoughts than your thoughts![[99]]
We are now, however, about to people the Fixed Stars. The only proof that they are the centres of planetary systems, resides in the assumption that these Stars are like the Sun; and as resembling him in their nature and qualities, so having the same offices and appendages:—independent sources of light, and thence probably of heat; therefore having attendant planets, to which they may impart such light and heat,—and these planets’ inhabitants living under and enjoying those benign influences. Everything here depends on this proposition, that the Stars are like the Sun; and it becomes essential to examine what evidence we have of the exactness of their likeness.[[100]] In the Preface to his Second Edition, the Essayist, whose scientific knowledge few will venture to impugn, boldly asserts that “man’s knowledge of the physical properties of the luminaries which he discerns in the skies, is, even now, almost nothing;” and “such being the state of our knowledge, as bearing on the doctrine of the plurality of worlds, the time appeared to be not inopportune for a calm discussion of the question,—upon which, accordingly,” he adds, “I have ventured in the following pages.” In the same Preface he has ably condensed into a single paragraph his views on the nature and extent of our present knowledge on the subject of the Fixed Stars.[[101]]
In the opening of the chapter devoted to this subject (ch. viii.), he admits “the special evidence,” as to the probability of these stars containing, in themselves, or in accompanying planets, inhabitants of any kind, “is, indeed, slight, either way.”
As to Clustered and Double stars, they appear to give us, he says, but little promise of inhabitants. In what degree of condensation the matter of these binary systems is, compared with that of our solar system, we have no means whatever of knowing: but even granting that each individual of the pair were a sun like ours, in the nature of its material, and its state of condensation, is it probable that it resembles our Sun also in having planets revolving about it? A system of planets revolving about, or among, a pair of Suns, which are at the same time revolving about one another, is so complex a scheme [apparently], so impossible to arrange in a stable manner, that the assumption of the existence of such schemes, without a vestige of evidence, can hardly require refutation. No doubt, if we were really required to provide such a binary system of Suns with attendant planets, this would be best done by putting the planets so near to one Sun that they should not be sensibly affected by the other; and this is accordingly what has been proposed. For, as has been well said by Sir John Herschell, of the supposed planets in making this proposal, “unless closely nestled under the protecting wing of their immediate superior, the sweep of the other Sun in his perihelion passage round their own, might carry them off, or whirl them into orbits utterly inconsistent with the existence of their inhabitants.” “To assume the existence of the inhabitants, in spite of such dangers, and to provide against the dangers by placing them so close to one Sun as to be out of the reach of the other, though the whole distance of the two may not, and as we know in some cases does not, exceed the dimensions of our solar system, is showing them all the favour which is possible. But in making this provision, it is overlooked that it may not be possible to keep them in permanent orbits so near to the selected centre. Their Sun may be a vast sphere of luminous vapour, and the planets plunged into this atmosphere may, instead of describing regular orbits, plough their way in spiral paths through the nebulous abyss of its central nucleus.”[[102]]
In dealing with the Single Stars, which are, like the Sun, self-luminous, can they be proved, like him, to be definite dense masses? [His density is about that of water.] Or are they, or many of them, luminous masses in a far more diffused state, visually contracted to points through their immense distance? Some of those which we have the best means of examining are one-third, or even less, in mass, than he: and if Sirius, for instance, be in this diffused condition, though that would not of itself prevent his having planets, it would make him so unlike our Sun, as much to break the force of the presumption that he must have planets as he has. Again: As far back as our knowledge of our Sun extends, his has been a permanent condition of brightness: yet many of the fixed stars not only undergo changes, but periodical, and possibly progressive changes:—whence it may be inferred, perhaps, that they are not, generally, in the same permanent condition as our Sun. As to the evidence of their revolution on their axis, this has been inferred from their having periodical recurrences of fainter and brighter lustre; as if revolving orbs with one side darkened by spots. Of these, five only can be at present spoken of by astronomers[[103]] with precision. Nothing is more probable than that these periodical changes indicate the revolution of these stellar masses on their axis—a universal law, apparently, of all the large compact masses of the Universe, but by no means inferring their being, or having accompanying planets, inhabited. The Sun’s rotation is not shown, intelligibly, connected with its having near it the inhabited Earth. In the mean time, in so far as these stars are periodical, they are proved to be, not like, but unlike our Sun. The only real point of resemblance, then, is that of being self-luminous, in the highest degree ambiguous and inconclusive, and furnishing no argument entitled to be deemed one from analogy. Humboldt deems the force of analogy to tend even in the opposite direction. “After all,” he asks,[[104]] “is the assumption of satellites [attendant planets] to the fixed stars, so absolutely necessary? If we were to begin from the outer planets, Jupiter, &c., analogy might seem to require that all planets have satellites:—yet this is not so with Mars, Venus, Mercury;” to which may now be added the thirty Planetoids—making a much greater number of bodies that have not, than that have satellites. The assumption, then, that the fixed stars are of exactly the same nature as the Sun, was originally a bold guess; but there has not since been a vestige of any confirmatory fact:—no planet, nor anything fairly indicating the existence of one revolving round a fixed star, has ever hitherto been discerned;—and the subsequent discovery of nebulæ; binary systems; clusters of stars; periodical stars; of varied and accelerating periods of such stars,—all seem to point the other way: leaving, though possibly facts small in amount, the original assumption a mere guess, unsupported by all that three centuries of most diligent, and in other respects, successful research, have been able to bring to light. All the knowledge of times succeeding Copernicus, Galileo, and Kepler, (who might well believe the stars to be in every sense suns);—among other things, the disclosure of the history of our own planet, as one in which such grand changes have been constantly going on; the certainty that in by far the greatest part of the duration of its existence it has been tenanted by creatures entirely different from those which give an interest, and thence a persuasiveness, to the belief of inhabitants in worlds appended to each star; the impossibility of which appears, in the gravest consideration of transferring to other worlds such interests as belong to our race in this world;—all these considerations, it would seem, should have prevented that old and arbitrary conjecture from growing up, among a generation professing philosophical caution and scientific discipline, into a settled belief. Finally, it will be time enough to speculate about the inhabitants of the planets which belong to such systems, as soon as we shall have ascertained that there are such planets,—or that there is one such.[[105]]
In the Dialogue, written after the first edition of the “Essay” had appeared, the Essayist greatly strengthened the position for which he had contended in it, by an important passage containing the results of the eminent astronomer M. Struve’s recent examination of double stars, and the result of his elaborate and comprehensive comparison of the whole body of facts in stellar astronomy. Among the brighter stars, he arrives at the conclusion, that every FOURTH such star is physically double; and that a completed knowledge of double stars may prove every THIRD bright star to be physically double! And in the case of stars of inferior magnitude, that the number of insulated stars, though indeed greater than that of such compound systems, is nevertheless only three times, perhaps only twice as great. Thus the loose evidence of resemblance between our Sun and the fixed stars becomes feebler the more it is examined; and the assumption of stellar planetary systems appears, when closely scrutinised, to dwindle away to nothing.[[106]]
Now, to so much of the foregoing facts and speculations as are contained in the Essay, from which we have faithfully and carefully extracted the substance, in order that our readers may judge for themselves, Sir David Brewster answers, in effect, and generally in words, thus:—
The greatest and grandest truth in astronomy, is the motion of the solar system, advancing with all the planets and satellites in the heavens, at the rate of fifty-seven miles a second, round some distant invisible body, in an orbit of such inconceivable dimensions, that millions of years may be required for a single orbit. When we consider that this centre must be a sun with attendant planets like our own, revolving in like manner round our sun, [?] or round their common centre of gravity, the mind rejects, almost with indignation, the ignoble sentiment that Man is the only being performing this immeasurable journey—and that Jupiter, Saturn, Uranus, and Neptune, with their bright array of regal train-bearers, are but as colossal blocks of lifeless clay, encumbering the Earth as a drag, and mocking the creative majesty of Heaven. From the birth of man to the extinction of his race [!] the system to which he belongs will have described but an infinitesimal arc in that grand cosmical orbit in which it is destined to move. This affords a new argument for the plurality of worlds. Since every fixed star must have planets, the fact of our system revolving round a similar system of planets, furnishes a new argument from analogy; for as there is at least one inhabited planet in the one system, there must for the same reason be one in the other, and consequently as many as there are systems in the Universe.[[107]] Thus our system is not absolutely fixed in space, but is connected with the other systems in the Universe.