It is hardly worth while, perhaps, even to sneer at the reveries of Fourier48 – but much has been said, latterly, of the hypothesis of Mädler49 – that there exists, in the centre of the Galaxy, a stupendous globe about which all the systems of the cluster revolve. The period of our own, indeed, has been stated – 117 millions of years.
That our Sun has a motion in space, independently of its rotation, and revolution about the system’s centre of gravity, has long been suspected. This motion, granting it to exist, would be manifested perspectively. The stars in that firmamental region which we were leaving behind us, would, in a very long series of years, become crowded; those in the opposite quarter, scattered. Now, by means of astronomical History, we ascertain, cloudily, that some such phænomena have occurred. On this ground it has been declared that our system is moving to a point in the heavens diametrically opposite the star Zeta Herculis : – but this inference is, perhaps, the maximum to which we have any logical right. Mädler, however, has gone so far as to designate a particular star, Alcyone in the Pleiades, as being at or about the very spot around which a general revolution is performed.
Now, since by ‘analogy’ we are led, in the first instance, to these dreams, it is no more than proper that we should abide by analogy, at least in some measure, during their development; and that analogy which suggests the revolution, suggests at the same time a central orb about which it should be performed: – so far the astronomer was consistent. This central orb, however, should, dynamically, be greater than all the orbs, taken together, which surround it. Of these there are about 100 millions. ‘Why, then,’ it was of course demanded, ‘do we not see this vast central sun – at least equal in mass to 100 millions of such suns as ours – why do we not see it – we, especially, who occupy the mid region of the cluster – the very locality near which, at all events, must be situated this incomparable star?’ The reply was ready – ‘It must be non-luminous, as are our planets.’ Here, then, to suit a purpose, analogy is suddenly let fall. ‘Not so,’ it may be said – ‘we know that non-luminous suns actually exist.’ It is true that we have reason at least for supposing so; but we have certainly no reason whatever for supposing that the non-luminous suns in question are encircled by luminous suns, while these again are surrounded by non-luminous planets: – and it is precisely all this with which Mädler is called upon to find any thing analogous in the heavens – for it is precisely all this which he imagines in the case of the Galaxy. Admitting the thing to be so, we cannot help here picturing to ourselves how sad a puzzle the why is it so must prove to all à priori philosophers.
But granting, in the very teeth of analogy and of every thing else, the non-luminosity of the vast central orb, we may still inquire how this orb, so enormous, could fail of being rendered visible by the flood of light thrown upon it from the ioo millions of glorious suns glaring in all directions about it. On the urging of this question, the idea of an actually solid central sun appears, in some measure, to have been abandoned; and speculation proceeded to assert that the systems of the cluster perform their revolutions merely about an immaterial centre of gravity common to all. Here again then, to suit a purpose, analogy is let fall. The planets of our system revolve, it is true, about a common centre of gravity; but they do this in connexion with, and in consequence of, a material sun whose mass more than counterbalances the rest of the system.
The mathematical circle is a curve composed of an infinity of straight lines. But this idea of the circle – an idea which, in view of all ordinary geometry, is merely the mathematical, as contradistinguished from the practical, idea – is, in sober fact, the practical conception which alone we have any right to entertain in regard to the majestic circle with which we have to deal, at least in fancy, when we suppose our system revolving about a point in the centre of the Galaxy. Let the most vigorous of human imaginations attempt but to take a single step towards the comprehension of a sweep so ineffable! It would scarcely be paradoxical to say that a flash of lightning itself, travelling forever on the circumference of this unutterable circle, would still, forever, be travelling in a straight line. That the path of our Sun in such an orbit would, to any human perception, deviate in the slightest degree from a straight line, even in a million of years, is a proposition not to be entertained : – yet we are required to believe that a curvature has become apparent during the brief period of our astronomical history – during the mere point – during the utter nothingness of two or three thousand years.
It may be said that Mädler has really ascertained a curvature in the direction of our system’s now well-established progress through Space. Admitting, if necessary, this fact to be in reality such, I maintain that nothing is thereby shown except the reality of this fact – the fact of a curvature. For its thorough determination, ages will be required; and, when determined, it will be found indicative of some binary or other multiple relation between our Sun and some one or more of the proximate stars. I hazard nothing, however, in predicting, that, after the lapse of many centuries, all efforts at determining the path of our Sun through Space, will be abandoned as fruitless. This is easily conceivable when we look at the infinity of perturbation it must experience, from its perpetually-shifting relations with other orbs, in the common approach of all to the nucleus of the Galaxy.
But in examining other ‘nebulæ’ than that of the Milky Way – in surveying, generally, the clusters which overspread the heavens – do we or do we not find confirmation of Mädler’s hypothesis? We do not. The forms of the clusters are exceedingly diverse when casually viewed; but on close inspection, through powerful telescopes, we recognize the sphere, very distinctly, as at least the proximate form of all : – their constitution, in general, being at variance with the idea of revolution about a common centre.
‘It is difficult,’ says Sir John Herschel,50 ‘to form any conception of the dynamical state of such systems. On one hand, without a rotary motion and a centrifugal force, it is hardly possible not to regard them as in a state of progressive collapse. On the other, granting such a motion and such a force, we find it no less difficult to reconcile their forms with the rotation of the whole system [meaning cluster] around any single axis, without which internal collision would appear to be inevitable.’
Some remarks lately made about the ‘nebulæ’ by Dr Nichol, in taking quite a different view of the cosmical conditions from any taken in this Discourse – have a very peculiar applicability to the point now at issue. He says:
‘When our greatest telescopes are brought to bear upon them, we find that those which were thought to be irregular, are not so; they approach nearer to a globe. Here is one that looked oval; but Lord Rosse’s telescope brought it into a circle…. Now there occurs a very remarkable circumstance in reference to these comparatively sweeping circular masses of nebulæ. We find they are not entirely circular, but the reverse; and that all around them, on every side, there are volumes of stars, stretching out apparently as if they were rushing towards a great central mass in consequence of the action of some great power.’ *
Were I to describe, in my own words, what must necessarily be the existing condition of each nebula, on the hypothesis that all matter is, as I suggest, now returning to its original Unity, I should simply be going over, nearly verbatim, the language here employed by Dr Nichol, without the faintest suspicion of that stupendous truth which is the key to these nebular phænomena.
And here let me fortify my position still farther, by the voice of a greater than Mädler – of one, moreover, to whom all the data of Mädler have long been familiar things, carefully and thoroughly considered. Referring to the elaborate calculations of Argelander51 – the very researches which form Mädler’s basis – Humboldt, whose generalizing powers have never, perhaps, been equalled, has the following observation:
‘When we regard the real, proper, or non-perspective motions of the stars, we find many groups of them moving in opposite directions; and the data as yet in hand render it not necessary, at
least, to conceive that the systems composing the Milky Way, or the clusters, generally, composing the Universe, are revolving about any particular centre unknown, whether luminous or non-luminous. It is but Man’s longing for a fundamental First Cause, that impels both his intellect and fancy to the adoption of such an hypothesis.’ †
The phænomenon here alluded to – that of ‘many groups moving in opposite directions’ – is quite inexplicable by Mädler’s idea; but arises, as a necessary consequence, from that which forms the basis of this Discourse. While the merely general direction of each atom – of each moon, planet, star, or cluster – would, on my hypothesis, be, of course, absolutely rectilinear; while the general path of all bodies would be a right line leading to the centre of all; it is clear, nevertheless, that this general rectilinearity would be compounded of what, with scarcely any exaggeration, we may term an infinity of particular curves – an infinity of local deviations from rectilinearity – the result of continuous differences of relative position among the multitudinous masses, as each proceeds on its own proper journey to the End.
I quoted, just now, from Sir John Herschel, the following words, used in reference to the clusters: – ‘On one hand, without a rotary motion and a centrifugal force, it is hardly possible not to regard them as in a state of progressive collapse.’ The fact is, that, in surveying the ‘nebulæ’ with a telescope of high power, we shall find it quite impossible, having once conceived this idea of ‘collapse’, not to gather, at all points, corroboration of the idea. A nucleus is always apparent, in the direction of which the stars seem to be precipitating themselves; nor can these nuclei be mistaken for merely perspective phænomena: – the clusters are really denser near the centre – sparser in the regions more remote from it. In a word, we see every thing as we should see it were a collapse taking place; but, in general, it may be said of these clusters, that we can fairly entertain, while looking at them, the idea of orbitual movement about a centre, only by admitting the possible existence, in the distant domains of space, of dynamical laws with which we are unacquainted.
On the part of Herschel, however, there is evidently a reluctance to regard the nebulæ as in ‘a state of progressive collapse’. But if facts – if even appearances justify the supposition of their being in this state, why, it may well be demanded, is he disinclined to admit it? Simply on account of a prejudice; – merely because the supposition is at war with a preconceived and utterly baseless notion – that of the endlessness – that of the eternal stability of the Universe.
If the propositions of this Discourse are tenable, the ‘state of progressive collapse’ is precisely that state in which alone we are warranted in considering All Things; and, with due humility, let me here confess that, for my part, I am at a loss to conceive how any other understanding of the existing condition of affairs, could ever have made its way into the human brain. ‘The tendency to collapse’ and ‘the attraction of gravitation’ are convertible phrases. In using either, we speak of the rëaction of the First Act. Never was necessity less obvious than that of supposing Matter imbued with an ineradicable quality forming part of its material nature – a quality, or instinct, forever inseparable from it, and by dint of which inalienable principle every atom is perpetually impelled to seek its fellow-atom. Never was necessity less obvious than that of entertaining this unphilosophical idea. Going boldly behind the vulgar thought, we have to conceive, metaphysically, that the gravitating principle appertains to Matter temporarily – only while diffused – only while existing as Many instead of as One – appertains to it by virtue of its state of radiation alone – appertains, in a word, altogether to its condition, and not in the slightest degree to itself. In this view, when the radiation shall have returned into its source – when the rëaction shall be completed – the gravitating principle will no longer exist. And, in fact, astronomers, without at any time reaching the idea here suggested, seem to have been approximating it, in the assertion that ‘if there were but one body in the Universe, it would be impossible to understand how the principle, Gravity, could obtain’ : – that is to say, from a consideration of Matter as they find it, they reach a conclusion at which I deductively arrive. That so pregnant a suggestion as the one quoted should have been permitted to remain so long unfruitful, is, nevertheless, a mystery which I find it difficult to fathom.
It is, perhaps, in no little degree, however, our propensity for the continuous – for the analogical – in the present case more particularly for the symmetrical – which has been leading us astray. And, in fact, the sense of the symmetrical is an instinct which may be depended on with an almost blindfold reliance. It is the poetical essence of the Universe – of the Universe which, in the supremeness of its symmetry, is but the most sublime of poems. Now symmetry and consistency are convertible terms: – thus Poetry and Truth are one. A thing is consistent in the ratio of its truth – true in the ratio of its consistency. A perfect consistency, I repeat, can be nothing but an absolute truth. We may take it for granted, then, that Man cannot long or widely err, if he suffer himself to be guided by his poetical, which I have maintained to be his truthful, in being his symmetrical, instinct. He must have a care, however, lest, in pursuing too heedlessly the superficial symmetry of forms and motions, he leave out of sight the really essential symmetry of the principles which determine and control them.
That the stellar bodies would finally be merged in one – that, at last, all would be drawn into the substance of one stupendous central orb already existing – is an idea which, for some time past, seems, vaguely and indeterminately, to have held possession of the fancy of mankind. It is an idea, in fact, which belongs to the class of the excessively obvious. It springs, instantly, from a superficial observation of the cyclic and seemingly gyrating, or vorticial movements of those individual portions of the Universe which come most immediately and most closely under our observation. There is not, perhaps, a human being, of ordinary education and of average reflective capacity, to whom, at some period, the fancy in question has not occurred, as if spontaneously, or intuitively, and wearing all the character of a very profound and very original conception. This conception, however, so commonly entertained, has never, within my knowledge, arisen out of any abstract considerations. Being, on the contrary, always suggested, as I say, by the vorticial movements about centres, a reason for it, also, – a cause for the ingathering of all the orbs into one, imagined to be already existing, was naturally sought in the same direction – among these cyclic movements themselves.
Thus it happened that, on announcement of the gradual and perfectly regular decrease observed in the orbit of Encke’s comet,53 at every successive revolution about our Sun, astronomers were nearly unanimous in the opinion that the cause in question was found – that a principle was discovered sufficient to account, physically, for that final, universal agglomeration which, I repeat, the analogical, symmetrical or poetical instinct of Man had predetermined to understand as something more than a simple hypothesis.
This cause – this sufficient reason for the final ingathering – was declared to exist in an exceedingly rare but still material medium pervading space;54 which medium, by retarding, in some degree, the progress of the comet, perpetually weakened its tangential force; thus giving a predominance to the centripetal; which, of course, drew the comet nearer and nearer at each revolution, and would eventually precipitate it upon the Sun.
All this was strictly logical – admitting the medium or ether; but this ether was assumed, most illogically, on the ground that no other mode than the one mentioned could be discovered, of accounting for the observed decrease in the orbit of the comet: – as if from the fact that we could discover no other mode of accounting for it, it followed, in any respect, that no other mode of accounting for it existed. It is clear that innumerable causes might operate, in combination, to diminish the orbit, without even a possibility of our ever becoming acquainted with even one of them. In the meantime, it has never been fairly shown, perhaps, w
hy the retardation occasioned by the skirts of the Sun’s atmosphere, through which the comet passes at perihelion, is not enough to account for the phænemenon. That Encke’s comet will be absorbed into the Sun, is probable; that all the comets of the system will be absorbed, is more than merely possible; but, in such case, the principle of absorption must be referred to eccentricity of orbit – to the close approximation to the Sun, of the comets at their perihelia; and is a principle not affecting, in any degree, the ponderous spheres, which are to be regarded as the true material constituents of the Universe. – Touching comets, in general, let me here suggest, in passing, that we cannot be far wrong in looking upon them as the lightning-flashes of the cosmical Heaven.
The idea of a retarding ether and, through it, of a final agglomeration of all things, seemed at one time, however, to be confirmed by the observation of a positive decrease in the orbit of the solid moon. By reference to eclipses recorded 2500 years ago, it was found that the velocity of the satellite’s revolution then was considerably less than it is now; that on the hypothesis that its motion in its orbit is uniformly in accordance with Kepler’s law, and was accurately determined then – 2500 years ago – it is now in advance of the position it should occupy, by nearly 9000 miles. The increase of velocity proved, of course, a diminution of orbit; and astronomers were fast yielding to a belief in an ether, as the sole mode of accounting for the phænomenon, when Lagrange came to the rescue. He showed that, owing to the configurations of the spheroids, the shorter axes of their ellipses are subject to variation in length; the longer axes being permanent; and that this variation is continuous and vibratory – so that every orbit is in a state of transition, either from circle to ellipse, or from ellipse to circle. In the case of the moon, where the shorter axis is decreasing, the orbit is passing from circle to ellipse, and, consequently, is decreasing too; but, after a long series of ages, the ultimate eccentricity will be attained; then the shorter axis will proceed to increase, until the orbit becomes a circle; when the process of shortening will again take place; – and so on forever. In the case of the Earth, the orbit is passing from ellipse to circle. The facts thus demonstrated do away, of course, with all necessity for supposing an ether, and with all apprehension of the system’s instability – on the ether’s account.
The Science Fiction of Edgar Allan Poe Page 35