THE DOG STAR AND HIS SYSTEM.
IN his last entertaining and instructive book,* Mr. Proctor gives us an account of the calculations and observations made on the size of the Dog Star, its distance from us, its motion in space, and most remarkable of all, the system to which it belongs,— which last astronomical observations are, to our minds, more im- pressive than any other of the recent discoveries or inferences of the same science, and for this reason, that while the other discoveries of our recent astronomy and the analysis of the various kinds of light received from the heavenly bodies, only reveal to us other suns, in the same incandescent state as our own, the latest news of Sirius appears to suggest that in connection with that "giant sun," as Mr. Proctor terms it,—a sun more than a million times as dis- tant from us, and more than four thousand times as big as our own, and with a disc near three hundred times as large as ours,—there appear to be certain vast planets, or rather, to speak popularly, non-luminous, already cooled-down suns, on which it is quite within the possibilities of things that life like that of our own tiny planet, though on an infinitely vaster scale, might exist. Now it is obvious that while our knowledge of the distant worlds of space is limited to bodies whose matter is chiefly in the condition of burning hydrogen and incandescent iron, it is impossible for such creatures as we are to draw any but negative inferences as to the chance of their being inhabited by intelligent beings of an organ- isation at all resembling our own. It would be quite as easy, and perhaps somewhat easier, to conceive of beings with human minds inhabiting the empty spaces, the ethereal depths, between the various suns, as to conceive of them in any sense living in a. world, where for us life would be as great a miracle as the preservation of Shadrach, Meshach, and Abednego in the fiery furnace. It is of course possible that such worlds may be the theatres of finite intelligences like man's, but certainly not more possible than that the ethereal "vacuum," as we call it, beyond the limits of our atmosphere is so also. The argument from analogy wholly fails as soon as the leading conditions of existence are so completely transformed as to require a complete change in kind, and not simply in degree, in the nature of the beings, if any, supposed to dwell there. 4!■ • Our Place Among the Infinities. A Serip of Essays contruttn; our Little Abode in Space and Time with the Infloltiee around us. By Ricnard.A. Proctor. London: Henry S. King and Co. But in the attendants of Sirius, if the explanation suggested by Mr. Proctor for the late Mr. Goldsmidt's discoveries is the right one, there might, presumably, at least, be life of the ter- restrial kind, though strangely different in degree from any to which we are accustomed. Mr. Goldsmidt detected not only a very faint companion of Sirius, but five other companion stars, and Mr. Proctor suggests that "their faintness may beat be explained by supposing that they are opaque bodies, which shine only by reflecting the light which they receive from their sun, Sirius." "If so," he goes on, "they must be globes of enormous real dimensions, the least of them probably exceeding our own sun many times in volume, while the greatest (so we may conceive, from the disturbance Sirius himself undergoes) must be so large and massive, that a thousand such orbs as our own Sun would not equal it, either in bulk or mass. We have here, then, a system differing altogether in character from our solar system the largest member of which is but equal in mass to about the 1,300th part of the Sun. The complete Sirian system may even outweigh Sirius himself, and its mass added to his must exert an attractive influence throughout an enormous portion of the stellar system. It would seem indeed not wholly impossible that Sirius holds a higher rank in the scale of Creation than our Sun and other similar orbs,—that compared with him these are as secondary orbs com- pared with primary."
This is certainly a wonderful conception,—a sun surrounded by opaque suns of a bulk comparable in some degree to his own, instead of forming much less than the quarter of a millionth part of it, as our Earth does of its Sun, of even as much as a thirteen- hundredth part of it, as Jupiter, the biggest of our planets, does. Let us try to follow out the conception a little further, supposing that these cooled-down suns, which, as it is assumed, are made visible to us only by reflected light, possess mighty atmospheres such as would render life there of a sort to a certain extent analogous to our own, possible. Now, in the first place, if the biggest of these cooled-down suns really contain a thousand times the volume of our own Sun, its diameter would be at least ten times the diameter of our Sun, and as that is considerably more than a hundred times the diameter of our Earth, its diameter would be a thousand times that of our Earth. In other words, speaking roughly, the diameter of such a world would considerably exceed eight millions of miles. To make the circuit of such a world as this would involve a journey which no human being could accom- plish, even if travelling at the highest known railway speed (say, even 1,000 miles a day), unless he lived for some 70 of our years, and travelled all the time at the same express-train speed from his birth to his death. But then we must remember that everything on such an orb would be, in all probability, on a different scale from ours. The mere force of gravity would be so immense, that no physical body suited to our earth could stir an inch if once planted there ; where it was placed, there it would remain for ever, for anything that any muscular power we know of could do to move it. If, therefore, there be life such as ours on such non-luminous suns as are the companions of the Dog Star, it must be either life en- dowed with muscular power indefinitely greater than any that we have any experience of, or life embodied in a physical organisation much more ethereal than any of which we know. Supposing the Alpine summits there, to bear the same proportion to the diameter of the globe which ours bear to the diameter of the Earth, they would reach a height of from four to six thousand miles above the level of the sea, instead of, like ours, only from four to six miles. And as, even with an atmosphere vastly denser than our own,—which, of course, other things being equal, it must be, with so enormous a force of gravity to compress it, —it is perhaps to be assumed that on mountains of such height the glaciers and snows would gather so as to become the sources of much vaster rivers than ours, it would not be a wholly rash conjecture that even the vegetation, as it would be indefinitely more rich and various, would also probably inde- finitely surpass ours in the dimensions it attained. In such a world, it is pretty clear that any beings who could live successfully at all must have powers of movement and probably of effort and resist- ance, surpassing ours more than ours surpass those of the caterpillar or the snail. It does not follow, of course, that the beings corre- sponding to men, if such there were, would grow to the height of five or six thousand feet, and be as tall as our lower Alpine summits,—so as to bear the same proportion to the dimen- sions of their world, as our height does to those of ours. But, since on the whole, there is no doubt that the average muscular power of creatures here is more or less in proportion to their size, that large dogs are more powerful than small dogs very much in the ratio of their size, and that the tiger, the elephant, and the rhino- ceros are vastly more competent to deal with powerful obstacles to their movement than is man himself,—at least in his savage state, —we may perhaps assume that any rational creature, even in a different universe from ours, must originally have had physical powers commensurate with the magnitude of the difficulties with which he had to deal. Thus it must, in all probability, be taken for granted that if life like ours exists on such a globe at all, it must be either embodied in far more attenuated organisms or in forms far vaster than any to which we are accustomed. We need not, indeed, suppose that the rational beings there, if they had bodies like ours, would tower to the height of moderate-sized moun- tains; that butterflies there would be forty feet long, and "toy terriers," if such there were, a thousand feet long; but we may fairly conjecture that the whole scale of the organisation of rational creatures must be, if only for the necessity it would be- under of overcoming the physical difficulties of a world in which, the weight of bodies would be so vast, distances so great, and- probably, rivers and vegetation of so enormous a size, of an order' of magnitude of which it is hardly possible for us to form any adequate conception.
But almost as remarkable as the magnitudes of such a world would be probably its astronomical phenomena. If there be five such cooled-down suns besides the still incandescent sun, Sirius, which is their primary, each of these huge solar worlds would have four moons at least of majestic size and brilliancy in its sky, in addition to any satellite moon or moons, of the nature of our Moon or Jupiter's moons, to illuminate the probably long night. Our own Sun, we know, rotates in about five - and - twenty days, and even supposing these solar planets of Sirius (one of which is supposed to have a diameter at least ten times the length of the Sun's), to rotate vastly more rapidly, it is hardly likely that its night should be shorter than two or more of our months. During that time, then, the inhabitants would be lighted not merely by any such moons or rings as might be appended to their world, just as our Moon or Saturn's ring is appended to the Earth or to Saturn, but also by mighty sun-moons such as we should have if our Sun had opaque companion-suns in his neighbourhood to reflect us back his light. All such sun-moons would of course, in relation to the world we are supposing, be moons only as regards the re- flected character of the light they give, not as regards their celestial path. So that such a world would have various years, one in relation to its path round its primary, Sirius, and another in relation to each of these solar-moons ; each of which, too, would cause a new day and night peculiar to itself, of the same length as- the day and night caused by Sirius-, though not coincident with them. Thus, besides the year, the day, and the night due to the sun. Sirius, there would be four other distinct years, days, and nights, to say nothing of any more properly lunar periods which would be due to the light of proper gatellites, if such there wore. When it is considered that with the in all probability extremely dense atmo- sphere of such a world,—supposing there to be atthosphere at all, for without atmosphere there would be really no analogies to the physical life on our own planet, —all the more beautiful phenomena of light, such as twilight, the gorgeous refractions of dawn and sun- set, the prismatic colours of the rainbow, and the reflected lights from the huge mountain-summits, would be of far greater beauty
and splendour than any of which we have experience, it is not too much to say that Mr. Proctor's speculation really introduces us to a probable universe of quite astounding possibilities, in which almost every physical phenomenon we know would pro- bably be magnified in dimensions, till it would look as little like what it lboks to us, as a drop of water under the solar microscope looks like the same drop when it is seen with the naked eye.
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