We must not fall into the error, however, of conceiving the somewhat indefinite girdle as at all remote, comparatively speaking, from the also indefinite lenticular cluster which it surrounds; and thus, for mere purpose of explanation, we may speak of our Sun as actually situated at that point of the Y where its three component lines unite; and, conceiving this letter to be of a certain solidity – of a certain thickness, very trivial in comparison with its length – we may even speak of our position as in the middle of this thickness. Fancying ourselves thus placed, we shall no longer find difficulty in accounting for the phænomena presented – which are perspective altogether. When we look upward or downward – that is to say, when we cast our eyes in the direction of the letter’s thickness – we look through fewer stars than when we cast them in the direction of its length, or along either of the three component lines. Of course, in the former case, the stars appear scattered – in the latter, crowded. – To reverse this explanation: – An inhabitant of the Earth, when looking, as we commonly express ourselves, at the Galaxy, is then beholding it in some of the directions of its length – is looking along the lines of the Y – but when, looking out into the general Heaven, he turns his eyes from the Galaxy, he is then surveying it in the direction of the letter’s thickness; and on this account the stars seem to him scattered; while, in fact, they are as close together, on an average, as in the mass of the cluster. No consideration could be better adapted to convey an idea of this cluster’s stupendous extent.
If, with a telescope of high space-penetrating power, we carefully inspect the firmament, we shall become aware of a belt of clusters – of what we have hitherto called ‘nebulæ’ – a band, of varying breadth, stretching from horizon to horizon, at right angles to the general course of the Milky Way. This band is the ultimate cluster of clusters. This belt is The Universe of Stars. Our Galaxy is but one, and perhaps one of the most inconsiderable, of the clusters which go to the constitution of this ultimate, Universal belt or band. The appearance of this cluster of clusters, to our eyes, as a belt or band, is altogether a perspective phænomenon of the same character as that which causes us to behold our own individual and roughly-spherical cluster, the Galaxy, under guise also of a belt, traversing the Heavens at right angles to the Universal one. The shape of the all-inclusive cluster is, of course generally, that of each individual cluster which it includes. Just as the scattered stars which, on looking from the Galaxy, we see in the general sky, are, in fact, but a portion of that Galaxy itself, and as closely intermingled with it as any of the telescopic points in what seems the densest portion of its mass – so are the scattered ‘nebulæ’ which, on casting our eyes from the Universal belt, we perceive at all points of the firmament – so, I say, are these scattered ‘nebulæ’ to be understood as only perspectively scattered, and as but a portion of the one supreme and Universal sphere.
No astronomical fallacy is more untenable, and none has been more pertinaciously adhered to, than that of the absolute illimitation of the Universe of Stars.38 The reasons for limitation, as I have already assigned them, à priori, seem to me unanswerable; but, not to speak of these, observation assures us that there is, in numerous directions around us, certainly, if not in all, a positive limit – or, at the very least, affords us no basis whatever for thinking otherwise. Were the succession of stars endless, then the background of the sky would present us an uniform luminosity, like that displayed by the Galaxy – since there could be absolutely no point, in all that background, at which would not exist a star. The only mode, therefore, in which, under such a state of affairs, we could comprehend the voids which our telescopes find in innumerable directions, would be by supposing the distance of the invisible background so immense that no ray from it has yet been able to reach us at all. That this may be so, who shall venture to deny? I maintain, simply, that we have not even the shadow of a reason for believing that it is so.
When speaking of the vulgar propensity to regard all bodies on the Earth as tending merely to the Earth’s centre, I observed that, ‘with certain exceptions to be specified hereafter, every body on the Earth tends not only to the Earth’s centre, but in every conceivable direction besides’.* The ‘exceptions’ refer to those frequent gaps in the Heavens, where our utmost scrutiny can detect not only no stellar bodies, but no indications of their existence : – where yawning chasms, blacker than Erebus, seem to afford us glimpses, through the boundary walls of the Universe of Stars, into the illimitable Universe of Vacancy, beyond. Now as any body, existing on the Earth, chances to pass, either through its own movement or the Earth’s, into a line with any one of these voids, or cosmical abysses, it clearly is no longer attracted in the direction of that void, and for the moment, consequently, is ‘heavier’ than at any period, either after or before. Independently of the consideration of these voids, however, and looking only at the generally unequable distribution of the stars, we see that the absolute tendency of bodies on the Earth to the Earth’s centre, is in a state of perpetual variation.
We comprehend, then, the insulation of our Universe. We perceive the isolation of that – of all that which we grasp with the senses. We know that there exists one cluster of clusters – a collection around which, on all sides, extend the immeasurable wildernesses of a Space to all human perception untenanted. But because on the confines of this Universe of Stars we are compelled to pause, through want of farther evidence from the senses, is it right to conclude that, in fact, there is no material point beyond that which we have thus been permitted to attain? Have we, or have we not, an analogical right to the inference that this perceptible Universe – that this cluster of clusters – is but one of a series of clusters of clusters, the rest of which are invisible through distance – through the diffusion of their light being so excessive, ere it reaches us, as not to produce upon our retinas a light-impression – or from there being no such emanation as light at all, in those unspeakably distant worlds – or, lastly, from the mere interval being so vast, that the electric tidings of their presence in Space, have not yet – through the lapsing myriads of years – been enabled to traverse that interval?
Have we any right to inferences – have we any ground whatever for visions such as these? If we have a right to them in any degree, we have a right to their infinite extension.
The human brain has obviously a leaning to the ‘Infinite’, and fondles the phantom of the idea. It seems to long with a passionate fervor for this impossible conception, with the hope of intellectually believing it when conceived. What is general among the whole race of Man, of course no individual of that race can be warranted in considering abnormal; nevertheless, there may be a class of superior intelligences, to whom the human bias alluded to may wear all the character of monomania.
My question, however, remains unanswered: – Have we any right to infer – let us say, rather, to imagine – an interminable succession of the ‘clusters of clusters’, or of ‘Universes’ more or less similar?
I reply that the ‘right’, in a case such as this, depends absolutely on the hardihood of that imagination which ventures to claim the right. Let me declare, only, that, as an individual, I myself feel impelled to the fancy – without daring to call it more – that there does exist a limitless succession of Universes, more or less similar to that of which we have cognizance – to that of which alone we shall ever have cognizance – at the very least until the return of our own particular Universe into Unity. If such clusters of clusters exist, however – and they do – it is abundantly clear that, having had no part in our origin, they have no portion in our laws. They neither attract us, nor we them. Their material – their spirit is not ours – is not that which obtains in any part of our Universe. They can not impress our senses or our souls. Among them and us – considering all, for the moment, collectively – there are no influences in common. Each exists, apart and independently, in the bosom of its proper and particular God.39
In the conduct of this Discourse, I am aiming less at ph
ysical than at metaphysical order. The clearness with which even material phænomena are presented to the understanding, depends very little, I have long since learned to perceive, upon a merely natural, and almost altogether upon a moral, arrangement. If then I seem to step somewhat too discursively from point to point of my topic, let me suggest that I do so in the hope of thus the better keeping unbroken that chain of graduated impression by which alone the intellect of Man can expect to encompass the grandeurs of which I speak, and, in their majestic totality, to comprehend them.
So far, our attention has been directed, almost exclusively, to a general and relative grouping of the stellar bodies in space. Of specification there has been little; and whatever ideas of quantity have been conveyed – that is to say, of number, magnitude, and distance – have been conveyed incidentally and by way of preparation for more definitive conceptions. These latter let us now attempt to entertain.
Our solar system, as has been already mentioned, consists, in chief, of one sun and seventeen planets certainly, but in all probability a few others, revolving around it as a centre, and attended by seventeen moons of which we know, with possibly several more of which as yet we know nothing. These various bodies are not true spheres, but oblate spheroids – spheres flattened at the poles of the imaginary axes about which they rotate: – the flattening being a consequence of the rotation. Neither is the Sun absolutely the centre of the system; for this Sun itself, with all the planets, revolves about a perpetually shifting point of space, which is the system’s general centre of gravity. Neither are we to consider the paths through which these different spheroids move – the moons about the planets, the planets about the Sun, or the Sun about the common centre – as circles in an accurate sense. They are, in fact, ellipses – one of the foci being the point about which the revolution is made. An ellipse is a curve, returning into itself, one of whose diameters is longer than the other. In the longer diameter are two points, equidistant from the middle of the line, and so situated otherwise that if, from each of them a straight line be drawn to any one point of the curve, the two lines, taken together, will be equal to the longer diameter itself. Now let us conceive such an ellipse. At one of the points mentioned, which are the foci, let us fasten an orange. By an elastic thread let us connect this orange with a pea; and let us place this latter on the circumference of the ellipse. Let us now move the pea continuously around the orange – keeping always on the circumference of the ellipse. The elastic thread, which, of course, varies in length as we move the pea, will form what in geometry is called a radius vector. Now, if the orange be understood as the Sun, and the pea as a planet revolving about it, then the revolution should be made at such a rate – with the velocity so varying – that the radius vector may pass over equal areas of space in equal times. The progress of the pea should be – in other words, the progress of the planet is, of course, – slow in proportion to its distance from the Sun – swift in proportion to its proximity. Those plants, moreover, move the more slowly which are the farther from the Sun; the squares of their periods of revolution having the same proportion to each other, as have to each other the cubes of their mean distances from the Sun.
The wonderfully complex laws of revolution here described, however, are not to be understood as obtaining in our system alone. They everywhere prevail where Attraction prevails. They control the Universe of Stars. Every shining speck in the firmament is, no doubt, a luminous sun, resembling our own, at least in its general features, and having in attendance upon it a greater or less number of planets, greater or less, whose still lingering luminosity is not sufficient to render them visible to us at so vast a distance, but which, nevertheless, revolve, moon-attended, about their starry centres, in obedience to the principles just detailed – in obedience to the three omniprevalent laws of revolution – the three immortal laws guessed by the imaginative Kepler, and but subsequently demonstrated and accounted for by the patient and mathematical Newton. Among a tribe of philosophers who pride themselves excessively upon matter-of-fact, it is far too fashionable to sneer at all speculation under the comprehensive sobriquet, ‘guess-work’. The point to be considered is, who guesses. In guessing with Plato, we spend our time to better purpose, now and then, than in hearkening to a demonstration by Alcmæon.40
In many works on Astronomy I find it distinctly stated that the laws of Kepler are the basis of the great principle, Gravitation. This idea must have arisen from the fact that the suggestion of these laws by Kepler, and his proving them à posteriori to have an actual existence, led Newton to account for them by the hypothesis of Gravitation, and, finally, to demonstrate them à priori, as necessary consequences of the hypothetical principle. Thus so far from the laws of Kepler being the basis of Gravity, Gravity is the basis of these laws – as it is, indeed, of all the laws of the material Universe which are not referable to Repulsion alone.
The mean distance of the Earth from the Moon – that is to say, from the heavenly body in our closest vicinity – is 237,000 miles. Mercury, the planet nearest the Sun, is distant from him 37 millions of miles. Venus, the next, revolves at a distance of 68 millions : – the Earth, which comes next, at a distance of 95 millions : – Mars, then, at a distance of 144 millions. Now come the nine Asteroids41 (Ceres, Juno, Vesta, Pallas, Astræa, Flora, Iris, Hebe and ) at an average distance of about 250 millions. Then we have Jupiter, distant 490 millions; then Saturn, 900 millions; then Uranus, 19 hundred millions; finally Neptune, lately discovered, and revolving at a distance, say of 28 hundred millions. Leaving Neptune out of the account – of which as yet we know little accurately42 and which is, possibly, one of a system of Asteroids – it will be seen that, within certain limits, there exists an order of interval among the planets. Speaking loosely, we may say that each outer planet is twice as far from the Sun as is the next inner one. May not the order here mentioned – may not the law of Bode43 – be deduced from consideration of the analogy suggested by me as having place between the solar discharge of rings and the mode of the atomic radiation?
The numbers hurriedly mentioned in this summary of distance, it is folly to attempt comprehending, unless in the light of abstract arithmetical facts. They are not practically tangible ones. They convey no precise ideas. I have stated that Neptune, the planet farthest from the Sun, revolves about him at a distance of 28 hundred millions of miles. So far good: – I have stated a mathematical fact; and, without comprehending it in the least, we may put it to use – mathematically. But in mentioning, even, that the Moon revolves about the Earth at the comparatively trifling distance of 237,000 miles, I entertained no expectation of giving any one to understand – to know – to feel – how far from the Earth the Moon actually is. 237,000 miles! There are, perhaps, few of my readers who have not crossed the Atlantic ocean; yet how many of them have a distinct idea of even the 3,000 miles intervening between shore and shore? I doubt, indeed, whether the man lives who can force into his brain the most remote conception of the interval between one milestone and its next neighbor upon the turnpike. We are in some measure aided, however, in our consideration of distance, by combining this consideration with the kindred one of velocity. Sound passes through 1100 feet of space in a second of time. Now were it possible for an inhabitant of the Earth to see the flash of a cannon discharged in the Moon, and to hear the report, he would have to wait, after perceiving the former, more than 13 entire days and nights before getting any intimation of the latter.
However feeble be the impression, even thus conveyed, of the Moon’s real distance from the Earth, it will, nevertheless, effect a good object in enabling us more clearly to see the futility of attempting to grasp such intervals as that of the 28 hundred millions of miles between our Sun and Neptune; or even that of the 95 millions between the Sun and the Earth we inhabit. A cannon-ball, flying at the greatest velocity with which a ball has ever been known to fly, could not traverse the latter interval in less than 20 years; while for the former it would require 590.
Our
Moon’s real diameter is 2160 miles; yet she is comparatively so trifling an object that it would take nearly 50 such orbs to compose one as great as the Earth.
The diameter of our own globe is 7912 miles – but from the enunciation of these numbers what positive idea do we derive?
If we ascend an ordinary mountain 44 and look around us from its summit, we behold a landscape stretching, say 40 miles, in every direction; forming a circle 250 miles in circumference; and including an area of 5000 square miles. The extent of such a prospect, on account of the successiveness with which its portions necessarily present themselves to view, can be only very feebly and very partially appreciated : – yet the entire panorama would comprehend no more than one 40,000th part of the mere surface of our globe. Were this panorama, then, to be succeeded, after the lapse of an hour, by another of equal extent; this again by a third, after the lapse of another hour; this again by a fourth after lapse of another hour – and so on, until the scenery of the whole Earth were exhausted; and were we to be engaged in examining these various panoramas for twelve hours of every day; we should nevertheless, be 9 years and 48 days in completing the general survey.
But if the mere surface of the Earth eludes the grasp of the imagination, what are we to think of its cubical contents? It embraces a mass of matter equal in weight to at least 2 sextillions, 200 quintillions of tons. Let us suppose it in a state of quiescence: and now let us endeavor to conceive of mechanical force sufficient to set it in motion! Not the strength of all the myriads of beings whom we may conclude to inhabit the planetary worlds of our system – not the combined physical strength of all these beings – even admitting all to be more powerful than man – would avail to stir the ponderous mass a single inch from its position.
The Science Fiction of Edgar Allan Poe Page 33