Complete Essays, Literary Criticism, Cryptography, Autography, Translations & Letters. Эдгар Аллан По
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than its interior. When the rupture occurred, then, some portion in each fragment must have been moving with greater velocity than the others. The superior movement prevailing, must have whirled each fragment round — that is to say, have caused it to rotate; and the direction of the rotation must, of course, have been the direction of the revolution whence it arose. All the fragments, having become subject to the rotation described, must, in coalescing, have imparted it to the one planet constituted by their coalescence. This planet was Neptune. Its material continuing to undergo condensation, and the centrifugal force, generated in its rotation, getting at length the better of the centripetal, as before in the case of the parent orb, a ring was whirled also from the equatorial surface of this planet; this ring, having been uniform in its constitution, was broken up, and its several fragments, being absorbed by the most massive, were collectively spherified into a moon. Subsequently, the operation was repeated, and a second moon was the result. We thus account for the planet Neptune, with the two satellites which accompany him.9
In throwing of a ring from its equator, the Sun re-established that equilibrium between its centripetal and centrifugal forces which had been disturbed in the process of condensation; but, as this condensation still proceeded, the equilibrium was again immediately disturbed, through the increase of rotation. By the time the mass had so far shrunk that it occupied a spherical space just that circumscribed by the orbit of Uranus, we are to understand that the centrifugal force had so far obtained the ascendency that new relief was needed; a second equatorial band was, consequently, thrown off, which, proving un-uniform, was broken up, as before in the case of Neptune; the fragments settling into the planet Uranus — the velocity of whose actual revolution about the Sun indicates, of course, the rotary speed of that Sun’s equatorial surface at the moment of the separation. Uranus, adopting a rotation from the collective rotations of the fragments composing it, as previously explained, now threw off ring after ring; each of which, becoming broken up, settled into a moon; — three moons, at different epochs, having been formed, in this manner, by the rupture and general spherification of as many distinct un-uniform rings.
By the time the Sun had shrunk until it occupied a space just that circumscribed by the orbit of Saturn, the balance, we are to suppose, between its centripetal and centrifugal forces had again become so far disturbed, through increase of rotary velocity, the result of condensation, that a third effort at equilibrium became necessary; and an annular band was therefore whirled off, as twice before; which, on rupture through un-uniformity, became consolidated into the planet Saturn. This latter threw off, in the first place, seven un-uniform bands, which, on rupture, were spherified respectively into as many moons; but, subsequently, it appears to have discharged, at three distinct but not very distant epochs, three rings whose equability of constitution was, by apparent accident, so considerable as to present no occasion for their rupture; thus they continue to revolve as rings. I use the phrase “apparent accident;” for of accident in the ordinary sense there was, of course, nothing; — the term is properly applied only to the result of indistinguishable or not immediately traceable law.
Shrinking still farther, until it occupied just the space circumscribed by the orbit of Jupiter, the Sun now found need of farther effort to restore the counterbalance of its two forces, continually disarranged in the still continued increase of rotation. Jupiter, accordingly, was now thrown off, passing from the annular to the planetary condition; and, on attaining this latter, threw off in its turn, at four different epochs, four rings, which finally resolved themselves into so many moons.
Still shrinking, until its sphere occupied just the space defined by the orbit of the Asteroids, the Sun now discarded a ring which appears to have had nine centres of superior solidity, and, on breaking up, to have separated into nine fragments, no one of which so far predominated in mass as to absorb the others.10 All therefore, as distinct although comparatively small planets, proceeded to revolve in orbits whose distances, each from each, may be considered as in some degree the measure of the force which drove them asunder; all the orbits, nevertheless, being so closely coincident as to admit of our calling them one, in view of the other planetary orbits.
Continuing to shrink, the Sun, on becoming so small as just to fill the orbit of Mars, now discharged this planet — of course by the process repeatedly described. Since he had no moon, however, Mars could have thrown off no ring. In fact, an epoch had now arrived in the career of the parent body, the centre of the system. The decrease of its nebulosity — which is the increase of its density, and which again is the decrease of its condensation, out of which latter arose the constant disturbance of equilibrium — must, by this period, have attained a point at which the efforts for restoration would have been more and more ineffectual just in proportion as they were less frequently needed. Thus the processes of which we have been speaking would everywhere show signs of exhaustion — in the planets, first, and secondly, in the original mass. We must not fall into the error of supposing the decrease of interval observed among the planets as we approach the Sun, to be in any respect indicative of an increase of frequency in the periods at which they were discarded. Exactly the converse is to be understood. The longest interval of time must have occurred between the discharges of the two interior; the shortest, between those of the two exterior, planets. The decrease of the interval of space is, nevertheless, the measure of the density, and thus inversely of the condensation, of the Sun, throughout the processes detailed.
Having shrunk, however, so far as to fill only the orbit of our Earth, the parent sphere whirled from itself still one other body — the Earth — in a condition so nebulous as to admit of this body’s discarding, in its turn, yet another, which is our Moon; but here terminated the lunar formations.
Finally, subsiding to the orbits first of Venus and then of Mercury, the Sun discarded these two interior planets; neither of which has given birth to any moon.
Thus from his original bulk — or, to speak more accurately, from the condition in which we first considered him — from a partially spherified nebular mass, certainly much more than five thousand, six hundred millions of miles in diamete — the great central orb and origin of our solar-planetary- lunar system, has gradually descended, by condensation, in obedience to the law of Gravity, to a globe only eight hundred eighty-two thousand miles in diameter; but it by no means follows, either that its condensation is yet complete, or that it may not still possess the capacity of whirling from itself another planet.
I have here given — in outline, of course, but still with all the detail necessary for distinctness — a view of the Nebular Theory as its author himself conceived it. From whatever point we regard it, we shall find it beautifully true. It is by far too beautiful, indeed, not to possess Truth as its essentiality — and here I am very profoundly serious in what I say. In the revolution of the satellites of Uranus, there does appear something seemingly inconsistent with the assumptions of Laplace; but that one inconsistency can invalidate a theory constructed from a million of intricate consistencies, is a fancy fit only for the fantastic. In prophesying, confidently, that the apparent anomaly to which I refer, will, sooner or later, be found one of the strongest possible corroborations of the general hypothesis, I pretend to no especial spirit of divination. It is a matter which the only difficulty seems not to foresee.11
The bodies whirled off in the processes described, would exchange, it has been seen, the superficial rotation of the orbs whence they originated, for a revolution of equal velocity about these orbs as distant centres; and the revolution thus engendered must proceed, so long as the centripetal force, or that with which the discarded body gravitates toward its parent, is neither greater nor less than that by which it was discarded; that is, than the centrifugal, or, far more properly, than the tangential, velocity. From the unity, however, of the origin of these two forces, we might have expected to find them as they are found — the one accurately counterbalancing the other. It has been shown, indeed, that the act of whirling-off is, in every case, merely an act for the preservation of the counterbalance.
After referring, however, the centripetal force to the omniprevalent law of Gravity,