Now, whatever opinion we form as to the exact character of the system of bodies pointed to by the researches of Leverrier and Baxendell—whether we suppose that system to form a zone around the sun, or that (as I believe) the system is merely due to the aggregation of meteoric perihelia in the sun’s neighborhood—we may be quite certain of this, that during a total solar eclipse the system could not fail to become visible. Hence there is a double objection to the view put forward by Mr. Lockyer and others. In the first place, it fails to account for the appearance presented by the corona; in the second place, it fails to render an account of the implied non-appearance of the system which, according to the researches of Leverrier and Baxendell, circles around the sun.
Fig. 34.—Scale of Planets
Jupiter and Saturn are shown in their true axial positions, Uranus and Neptune in the axial positions inferred from the motions of their satellites
We know that the sun is the sole source whence light and heat are plentifully supplied to the worlds which circle around him. The question immediately suggests itself—Whence does the sun derive those amazing stores of force from whence he is continually supplying his dependent worlds? We know that, were the sun a mass of burning matter, he would be consumed in a few thousand years. We know that, were he simply a heated body, radiating light and heat continually into space, he would in like manner have exhausted all his energies in a few thousand years—a mere day in the history of his system. Whence, then, comes the enormous supply of force which he has afforded for millions on millions of years, and which also our reason tells us he will continue to afford while the worlds which circle around him have need of it—in other words, for countless ages to come?
Now, there are two ways in which the solar energies might be maintained. The mere contraction of the solar substance, Helmholtz tells us, would suffice to supply such enormous quantities of heat that, if the heat actually given out by the sun were due to this cause alone, there would not, in many thousands of years, be any perceptible diminution of the sun’s diameter. But, secondly, the continual downfall of meteors upon the sun would cause an emission of heat in quantities vast enough for the wants of all the worlds circling round him; while his increase of mass from this cause would not be rendered perceptible in thousands of years, either by any change in his apparent size or by changes in the motions of his family of worlds.
It seems far from unlikely that both these processes are in operation at the same time. Certainly the latter is, for we know, from the motions of the meteoric bodies which reach the earth, that myriads of these bodies must continually fall upon the sun. And if the corona and Zodiacal Light really be due to the existence of flights of meteoric systems circling around the sun, or to the existence in his neighborhood of the perihelia of many meteoric systems, then there must be a supply of light and heat from this source very nearly if not quite sufficient to account for the whole solar emission.
It is well worthy of notice, too, that the association between meteors and comets has an important bearing on this question. We know that the most remarkable characteristic of comets is the enormous diffusion of their substance. Now, in this diffusion there resides an enormous fund of force. The contraction of a large comet to dimensions corresponding to a very moderate mean density would be accompanied by the emission of a vast supply of heat. And the question is worth inquiring into, whether we can indeed assume that the meteors which reach our atmosphere are solid bodies, and not rather of cometic diffusion; since it is difficult otherwise to account for the light and heat which they emit. Friction through the rarer upper strata of our atmosphere will certainly not account for these phenomena; nor, I think, will the compression of the atmosphere in front of the meteors; on the other hand, the sudden contraction of a diffused vapor would be accompanied by precisely such results. But, be this as it may, it is certain that a large portion of the substance of every comet is in a singularly diffused state. And since the meteoric systems circling in countless millions round the sun are, in all probability, associated in the most intimate manner with comets, we may recognize in this diffusion, as well as in the mere downfall of meteors, the source of an enormous supply of light and heat.
And lastly, turning from our sun to the other suns which shine in uncounted myriads throughout space, we see the same processes at work upon them all. Each star-sun has its coronal and its zodiacal disks, formed by meteoric and cometic systems; for otherwise each would quickly cease to be a sun. Each star-sun emits, no doubt, the same magnetic influences which give to the Zodiacal Light and to the solar corona their peculiar characteristics. And thus the worlds which circle round those orbs may resemble our own in all those relations which we refer to terrestrial magnetism, as well as in the circumstance that on them also there must be, as on our own earth, a continual downfall of minute meteors. In those worlds, perchance, the magnetic compass directs the traveler over desert wastes or trackless oceans; in their skies, the aurora displays its brilliant streamers; while, amid the constellations which deck their heavens, meteors sweep suddenly into view, and comets extend their vast length athwart the celestial vault, a terror to millions, but a subject of study and research to the thoughtful.