Nebula

“ We are led, irresistibly as it seems, to regard the whole mass of such a nebula, as an aggregation of vaporous rolls and streaks, assuming such forms as thin volumes of smoke or vapor often assume in our atmosphere, and assuming, like them, different shapes according to the quantity of light which comes to us from them. If, as soon as one of these new filaments or webs of a nebula comes into view, we should say, Here we have a new array of suns and of worlds, we should judge as fantastically, as any one who should combine the like imaginations with the varying cloud-work of a summer-sky. ”

“ But we have learned too late, now, for in less than twenty hours the nebula's whirling will have reached its critical point, will have sent its vast flaming mass hurtling out across our universe, our Galaxy, in all directions, to carry destruction and death to all the peoples of our suns and worlds! ”

“ The whole surface of their world they sheathed with smooth, heat-reflecting metal, and then descended in all their hordes into the countless mighty caverns that honeycombed all their great world, taking up their life again in those cool depths, safe from the nebula's heat. ”

“ Ages passed over them while they lived thus in their world's depths, but still the nebula contracted, closed in upon them, in that vast, remorseless cycle that is nature's law throughout the universe. Closer and closer crept its fires toward the metal-sheathed world of the nebula people, until at last they saw that soon those fires would envelop their world and annihilate it, unless they were turned back in some way. ”

“ All these stars were part of a great system that formed a nebula. It explained the mystery of the nebulae.
And there were now other nebulae approaching, as this grew smaller. They took on the resemblance of stars, and they began to repeat the process of closing in as the stars had done. The stars, universes within universes! And those universes but nebulae in another great universe! Suddenly I began to wonder. Could there be nothing more in infinity than universe after universe, each a part of another greater one? ”

“ Our flight now carried us so rapidly through the flocks of solar bodies--flocks, past counting unless to their heavenly Shepherd,--that scarcely could they expand themselves before us into the magnitude of moons, before they sank behind us into pale nebular gleams; and their planetary earths could not reveal themselves for a moment to the transcendent rapidity of our course. At length Sirius and all the brotherhood of our constellations and the galaxy of our heavens stood far below our feet as a little nebula amongst other yet more distant nebulae. ”

“ Our planet showed at that time the aspect of those vague gaseous nebulæ which the telescope discovers on the floor of the skies and which the spectroscope analyses. The solar nebula in the course of condensation floated among the stars. All humanity with its history, every one of us with all his energies, all the living beings of this Earth, were contained in the germ of that nebula and its forces; but the beings and the things which we know were not to come into existence until after a long incubation of centuries. ”

“ After we have resolved many a dim nebula in the starry sky, and found it all ablaze with suns and worlds, there will still hang, faint and far before us, hazy magnificences which we have not apprehended. ”

“ We must not forget that the only spiral nebulæ which lie within the reach of our powers of observation, whether telescopic or photographic, appear to be objects of enormously greater cosmical magnificence than was that primæval nebula from which so insignificant an object as the solar system has sprung. The great spirals, so far as we can tell at present, appear to be thousands of times, or even millions of times, greater in area than the solar system. ”

“ As the ages roll by, the nebula must gradually come to dispose itself, so that the moment of momentum shall be maintained, notwithstanding that the energy may have wasted away to no more than a fraction of its original amount. ”

“ It demonstrates, by a line of reasoning the cogency of which cannot be impugned, that the famous stars are not standing out in front of the nebula, that they are not sunk far behind, but that they do veritably lie at the heart of the nebula itself, the combined object forming one glorious organization. To simplify the application of the argument, let us assume that the visible heavens are constituted, not of hosts of stars and nebulae, but of one single star and one single nebula. ”

“ In subsequent chapters we are to present the evidence for the belief that this earth of ours, as well as the sun and all the other bodies which form the solar system, did once originate in a nebula. According to this view the materials which at present are found in 50the globes of the solar system were once distributed over a vast extent of space as a fire-mist, or nebula. It is surely very pertinent to be able to show that a nebula, such as we suppose to have been the origin of our system, is not a mere figment of the imagination. ”

“ We know that the great nebula is growing slowly smaller, that through the eons it contracts to form new blazing stars, but what its constitution may be, what mysteries it may hide, has never been known, since it would be annihilation for any ship to approach too near to its fiery splendor, and all our interstellar traffic has detoured always far around its flaming mass. ”

“ A few evenings ago I lighted on a strange nebula, of which here is a figure! and since I am about it I shall add a figure of one of the resolvable nebulæ in the greater magellanic cloud. The equatorial is at last erected, and the revolving roof (upon a plan of my own) works perfectly well, but I am sorry to say that the nights in which it can be used to advantage are rare, even rarer than in England, as, in spite of the clearness of the sky, the stars are ill-defined and excessively tremulous. ”

“ Some detect with the naked eye the light that comes from the nebula in the Sword’s-Handle of Orion, which is thought to contain two trillions, two hundred billions of stars; and if all these stars are no nearer to each other than Alpha Centauri is to our sun, it cannot be otherwise than that some of them are so distant their light may have been travelling for a million years before it comes to our sight. ”

“ Nothing falls to the ground without some heat being generated. Now, when this great nebula first began its remarkable career, by the action of gravity all the particles in it were drawn toward the centre; little by little they fell in, and the nebula became smaller. We are not now concerned with the origin of the planets—we leave that aside; we are only contemplating the part of the nebula which remained to become the sun. Now these particles being drawn inward each generated some heat, so as the nebula contracted its temperature rose. ”

“ The light with which it glows is no reflected sunlight. The nebula is indeed indebted to no foreign source for that weird—I had almost said ghostlike—radiance which it gives forth. The light comes from the nebula itself. ”

“ Nearer and nearer we flashed toward it, with Sar Than and Jor Dahat beside me gazing forward, their interest as tense as my own. And now we saw that the pit was of gigantic size, its circular mouth all of five miles in diameter, and that from its center there drove up toward the zenith a flickering beam of pale and ghostlike white light, so pale as hardly to be visible, a livid white ray that stabbed straight up toward the fires of the nebula far above. ”

“ The grouping of the stars of the first magnitude, some scattered nebula, rivalling in splendor the milky way, and tracks of space remarkable for their extreme blackness, give a particular physiognomy to the Southern sky. ”

“ The Greater Cloud is much brighter to the naked eye than the Lesser, and it is much more complex and interesting in the telescope. It contains, moreover, the wonderful Looped Nebula, of which we have already spoken.
Both Clouds consist of gaseous nebulae and star-clusters on a background of vague nebulosity and crowds of almost indistinguishable stars. But the white nebulae shun the Clouds, just as they shun the Milky Way. ”

“ The pictures, at which we have been looking, will suffice to make clear the criterion, which astronomers now possess, for deciding whether an object which looks nebulous is really a gaseous nebula, or ought rather to be regarded as a star-cluster. ”

“ Thus the various stages in the evolution of a system are to be witnessed, not indeed in the transformation of a single nebula, but by observing a properly arranged series of nebulæ in all gradations, from the diffused luminous haze to a star with a faint nebulous surrounding. ”

“ The meteors, or little planets, making up the nebula, attract each other, like all other bodies, and when they get close enough they are drawn together and dense masses of matter, or cores, are built up. The largest core is seen in the center of a spiral nebula, and as it becomes more compact it grows hotter and a Sun is made, while the other and smaller cores turn round it and attract little planets to them. And so the cores grow in size, and with more and more weight bearing toward their centers the gases are forced out and these make the air and water. ”

“ Would it be more reasonable to believe that the presence of the star in that particular locality of the heavens was only an accidental circumstance due to the line of vision from the nebula to the star passing through the eye, or that it was due to the fact that there was some physical connection between the two bodies, in which case, of course, the star would lie within the confines of the nebula, and the contiguity would be real as well as apparent? ”

“ Not only, therefore, are we driven to the inference that our solar system was once a vaporous nebula, but we find that the mere contraction of such a nebula, under the influence of the enormous mutual gravitation of its particles, carries with it the explanation of both the more general and the more particular features of the present system. ”

“ Some extraordinary force or forces have set the great nebula to spinning thus, and if we could venture out to the nebula, discover the nature of those forces, we might be able to counteract them, to stop the nebula's spin and save our suns and worlds. ”

“ In this cycle this great nebula followed, but because of its vast size the inner, denser portions had contracted with much greater speed than the outer parts, forming a great solid world, in time, while the outer parts were still but fiery gas. This solid world spun at the center of the great space formerly occupied by the gases that had contracted to form it, and it was warmed and lit eternally by the encircling fires of the nebula all around it, and shut off from the outside universe by those fires. ”

“ But we may be assured that, in general, whatever elements are present in the nebula will be widely dispersed through its extent. If from different parts of the nebula two globes are formed by condensation, though we should not affirm, and though in fact we could not believe, that those globes would be of identical composition, yet we should reasonably expect that the elementary bodies which entered into their composition would be in substantial agreement. If one element, say iron, was abundant in one globe, we should expect that iron would not be absent from the other. ”

“ The solid materials may again become transformed into a stupendous glowing nebula, and then, in the course of the tedious contraction of this nebula, another protracted period of brilliance will diversify the career of this great body, and may last long enough for the evolution of planets and of whole races of highly organized creatures. ”

“ Broken fragments in a gaseous mass of an excessively high temperature the first stage of a nebula.—From what has already been shown, it will be seen that after the colliding of the two dark bodies the first condition of the resulting nebula would be an enormous space occupied by broken fragments of all sizes dashing against each other with tremendous velocities, like the molecules in a perfect gas. ”

“ The origin of the nebula thus presents itself to the reason as a problem which demands solution no less than the origin of the planets. All the properties and laws of the nebula require to be accounted for. ”

“ While new cosmic bodies arise and develop, out of rotating masses of nebula in some parts of the universe, in other parts old, extinct, frigid suns come into collision, and are once more reduced by the heat generated to the condition of nebulæ. ”

“ It is obvious that, if lines be imagined in the field of view, winding around through all those portions of a nebula which have exactly equal brightness, these lines, transferred to our chart of stars, will give a faithful representation of the nebula and of its minutiæ, and of the suddenness as well as of the amount of transition from one degree of shade to another. ”

“ We shall therefore suppose that the evolution of the nebula proceeds solely in consequence of the mutual attractions of its various parts. In its original formation the nebula receives a certain endowment of energy and a certain endowment of moment of momentum; the mere fact that we see the nebula, the fact that it radiates light, shows that it must be expending energy, and the decline of the energy will proceed continuously from the formation 243of the object. ”