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ing it with JUPITER- the bulk of which is 1331 times greater than that of the Earth-his density is, as a whole, only a quarter of that of the Earth-not greater than it would be as a sphere of water; and he is conjectured to be such, and the existence of his belts to be lines of clouds, fed with vapours raised by the sun's action on such a watery sphere-the lines of such clouds being of so steady and determined a character, in consequence of his great rotatory velocity. Equal bulk for equal bulk, he is lighter than the Earth, but of course much heavier altogether; and as he is five times the Earth's distance from the Sun, he must get a proportionally smaller amount of light and heat, and even that diminished by the clouds enveloping him to so great an extent. What a low degree of vitality, and what kind of organisation must animal existence possess, to suit such physical conditions, especially with reference to gravity, which, at his surface, is nearly two and a half times that on the Earth! Boneless, watery, pulpy inhabitants of the cold waters; or they may be frozen so far as to exclude the idea of animal existence; or it may be restricted to shallow parts in a planet of ice.* But if this be so, to what end his gorgeous array of satellites?- his four moons? "Precisely the same," answers our pertinacious Essayist, "as the use of our moon during the count
less ages before man was placed on the earth; while it was tenanted by corals, madrepores, shell-fish, belemnites, the cartilaginous fishes of the old red sandstone, or the Saurian monsters of the lias. With these differences, it is asked, what becomes of analogy-of resemblances justifying our belief that Jupiter is inhabited like ourselves?
To this answers Sir David Brewster-Jupiter's great size " is alone a proof that it must have been made for some grand and useful purpose:" it is flattened at its poles; revolves on its axis in nearly ten hours; has different climates and seasons; and is abundantly illuminated, in the short absence of the sun, by its four moons, giving him, in fact," perpetual moonlight." Why does the sun give it days, nights, and years? Why do its moons irradiate its continents and seas? Its equatorial breezes blow perpetually over its plains? To what purpose could such a gigantic world have been framed, unless to supply the wants, and minister to the happiness, of living beings? Still, it is admitted,† "that certain objections or difficulties naturally present themselves." The distance of Jupiter from the sun precludes the possibility of sufficient light and heat from that quarter, to support either such vegetable or animal life as exists on the earth; the cold must be very intense-its rivers and seas must be tracks and fields of ice.‡
Essay, p. 281, 289.
+ Brewster, p. 60. To descend, for a moment, to details. Sir David Brewster will not allow himself to be driven to elect between the icy or watery constituency of Jupiter. He declares direct experiment to have proved that it is neither; that if Jupiter were a sphere of water, the light reflected from his surface, when in his quadratures, must contain, as it does not, a large portion of polarised light; and if his crust consist of mountains, precipices, and rocks of ice, some of whose faces must occasionally reflect the incident light at nearly the polarising angle, the polarisation of their light would be distinctly indicated. The Essayist, in his Dialogue, "doubts whether the remark is applicable; for Jupiter's watery or icy mass must be clothed in a thick stratum of air, and aqueous vapour, and clouds. But even were the planet free from clouds, the parts of the planet's surface from which polarised light would be reflected, would be only as points compared with the whole surface; and the common light reflected from the whole surface would quite overwhelm and obliterate the polarised light."-Dial. p. 64. We cite this as a sample of the ingenuity of both disputants, in a point of scientific contact. Whether Sir David's conjectural polarised light be or be not thus obliterated, in our view the item in dispute is quite lost in the general question, and the great principles on which its solution depends. If driven to elect between ice and water, asks Sir David playfully, " may we not, upon good grounds, prefer the probable ice to the possible water, and accommodate the inhabitants of Jupiter with very comfortable quarters, in huts of snow and houses of rystal, warmed by subterranean heat, and lighted with the hydrogen of its waters, d its cinders not wholly deprived of their bitumen ?"-Pp. 236, 237. The answer his opponent would be obvious.
But it may be answered, that the temperature of a planet depends on other causes the condition of its atmosphere, and the internal heat of its mass-as is the case with our earth; and such "may" be the case in Jupiter; and, "if" so, may secure a temperature sufficiently genial to sustain such animal and vegetable life as ours; yet, it is owned, it cannot "increase the feeble light which Jupiter derives from the sun;" but an enlargement of the pupil of the eye, and increased sensibility of the retina, would make the sun's light as brilliant to Jovians as to us."* Besides, a brilliant phosphorescent light "may" be excited in the satellites by the sun's rays. Again, the day of ten hours may be thought insufficient for physical repose; but, it is answered, five hours' repose are sufficient for five of labour. "A difficulty of a more serious kind,† however, is presented by the great force of gravity on so gigantic a planet as Jupiter;" but Sir David gives us curious calculations to show that a Jovian's weight would be only double that of a man on the earth.
Struck by such a formidable array of differences, when he was in quest of resemblances only,
"Alike, but, oh! how different! " Sir David rebukes the sceptic for forming so low an opinion of Omnipotent Wisdom, as to assume that "the inhabitants of the planets must be either men, or anything resembling them;-is it," he asks, "necessary that an immortal soul should be hung upon a skeleton of bone, or imprisoned in a cage of cartilage and skin? Must it see with two eyes, and bear with two ears, and touch with ten fingers, and rest on a duality of limbs? May it not rest in a Polyphemus with one eyeball, or in an Argus with a hundred? May it not reign in the giant forms of the Titans, and direct the hundred hands of Briareus? The being of another world may have his home in subterranean cities, warmed by central fires; or in crystal caves, cooled by ocean tides; or he may float with the Nereids upon the deep; or mount upon wings as eagles; or
rise upon the pinions of the dove, that he may flee away, and be at rest!"§
Let us pause at this point, and see how the question stands on the showing of the respectively imaginative and matter-of-fact disputants themselves. Sir David Brewster, being bound to show that analogy forces us to believe Jupiter inhabited, is compelled to admit a series of signal discrepancies in physical condition; expecting his opponent, in turn, to admit such a series of essential alterations, both of inert matter and organisation, as will admit of what?
totally different modes of animal and intellectual existence-so different, as to drive a philosopher into the fantastic dreams in which we have just seen him indulging. Not so the Essayist, a master of the Inductive Philosophy. He does not presume impiously to limit Omnipotence; but reverently owns His power to create whatever forms and conditions of existence He pleases. But when it is asserted that He has, in fact, made beings wholly different from any that we see," he cannot believe this without further evidence." || And on this very subject of the imaginary inhabitants of Jupiter, he says, after reading what his heated and fanciful opponent has advanced,"You are hard," he makes an objector say, 66 on our neighbours in Jupiter, when you will not allow them to be anything better than boneless, watery, pulpy creatures."" To which he answers, "I had no disposition to be hard on them when I entered upon these speculations. I drew, what appeared to me, probable conclusions from all the facts of the case. If the laws of attraction, of light, of heat, and the like, be the same there as they are here, which we believe to be certain, the laws of life must also be the same; and, if so, I can draw no other conclusions than those which I have stated." ¶
Says the Essayist, I know that my Maker can invest with the intellect of a Newton, each of
a fact; or I must believe in any kind of nonsense that any one can imagine.
The planet Jupiter affords a fair sample of the procedure of the Essayist and his opponent, with reference to all the other primary planets of the Solar system. From Mercury, in redhot contiguity to the Sun, to Neptune, which is at thirty times the Earth's distance from it, and from which as we have seen it derives only one ninehundredth part of the light and heat imparted to ourselves by the Sun,-Sir David Brewster will have all inhabited, and the physical condition of each correspondingly altered to admit of it: central heat, and eyes the pupils of which are sufficiently enlarged, and the retina's sensibility sufficiently increased, to admit of seeing with nine hundred times less light than is requisite for our own organs of sight! "Uranus and Neptune," concludes the triumphant Pluralist*-nothing daunted by the overwhelming evidences of physical difference of condition" are doubtless"-with the Sun-" the abodes of Life and Intelligence the colossal temples where their Creator is recognised and worshipped the remotest watch-towers of our system, from which his works may be better studied, and his glories more easily descried!"
Why, with such elastic principles of analogy as his, stop short of peopling the Meteoric Stones with rational inhabitants? whom, and whose doings, as in the case of the Moon, magnificent" instrument, yet to be constructed, may discover to us?
nearly equal-about the same as that of ironstone; while the density of the thoroughly-baked planet Mercury is equal to that of gold. "Now it appears, on the contrary," he continues, "that the density of Jupiter very little exceeds that of water; that of Uranus and Neptune is exactly that of water; while Saturn is so light, that it would float in water like a globe of pine wood. . . . The seas and oceans of these planets must consist of a liquid far lighter than water. It is computed that a liquid on Jupiter, which would be analogous to the terrestrial oceans, would be three times lighter than sulphuric ether, the lightest known liquid; and would be such that cork would scarcely float in it!"
Thus much for the planets,—before quitting which, however, we may state that, according to Dr Lardner, about as staunch a Pluralist as his admirer Sir David Brewster, a greater rapidity of rotation, and smaller intervals of light and darkness, are among the characteristics distinguishing the group of major planets from the terrestrial group. He also adds that another "striking distinction" is the comparative lightness of the matter constituting the former. The density of Venus, Mars, and our earth, is
Commending these trifling discrepancies to Sir David's attention, while manufacturing his planetary inhabitants in conformity with them, shall we now follow his flight beyond the solar system, and get among the Fixed Stars? Here we are gazing at the Dog-Star! "I allow," says a pensive objector to the Essayist, "that if you disprove the existence of inhabitants in the planets of our system, I shall not feel much real interest in the possible inhabitants of the Sirian system. Neighbourhood has its influence upon our feelings of regard,— even neighbourhood on a scale of millions of miles!"
Here our Pluralist is quite at home, and evidently in great favour. The stars twinkle and glitter with delight at his gleeful approach, to elevate them into moral and intellectual dignity, and at the same time, perhaps, select "some bright particular" one, to be hereafter distinguished as the seat of his own personal existence; whence he is to spend eternity in radiating astronomical emanations throughout infinitude.
"Then, unembodied, doth he trace,
By steps each planet's heavenly way? A Thing of Eyes, that all survey, A Thought Unseen, yet seeing all! "§ He stands in the starry solitude, waving his wand, and lo! he peoples
* Dial., p. 76.
§ Lord Byron-Hebrew Melodies. The philosopher will at the close of his eloquent Treatise," with a new sense, the he is to study."-P. 259.
+ Museum, &c., vol. i. p. 35.
+ Dial., p. 23. scan," says Sir David, lofty spheres in which
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." * 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! 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!+
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. § 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. ||
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." *
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† 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, "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 ; See them specified, p. 251.
Cosmos, iii. 373.
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,
Essay, pp. 243, 244.