APPENDIX V
A Journey with Coggia's Comet
[Reprinted from Home Words]
This comet, which last year excited so much interest, is supposed by some to be the same which appeared in the year 1737. If so, it is beyond the power of the human intellect to calculate the number of miles (millions upon millions) which it has travelled since that date; we may, however, in imagination, travel with it on one of its journeys.
Starting off then, as soon as it has made its perihelion passage, we are carried in the course of about six months to such a distance that this comparatively insignificant world (of which nevertheless we are all anxious to get a good slice) disappears entirely from our view, and the larger planets of this system are reduced to mere specks of light. The sun itself, which here scorches us at noonday, only appears there as a very minute star, just a small yellow speck. But meantime other suns, some of them of far greater magnitude and superior brilliancy than the sun we have left behind, gradually come into sight, and some of the "nebulæ," which appear to us here as so many bits of faint hazy light, some of them no larger than a crown piece, now appear to our unassisted vision in all the glorious majesty of suns and worlds and systems of worlds, all revolving round each other in the most regular and systematic order; for, as Milton says in Paradise Lost, "Order is Heaven's first law."
After our steed had carried us for the space of about seventy years in a direct onward course through systems of worlds by us from this world unseen, we should begin to return homewards, but by a different route from that by which we went out; and we should consequently have a constantly varying scene presented to our view. How awfully grand, for instance, would be the change, as we gradually lost sight of our yellow sun, to find ourselves arriving in sight and under the influence of a sun of a rich crimson red colour, and again after a few years to find ourselves in the presence of a green or a blue sun! Yet it is more than probable that such would be the case, for the sky is spangled with suns of all colours.
In the course of about 137 years from the time when we set out we should be returned sufficiently near to this world to enable its inhabitants to catch sight of our steed's tail. And then, after all this long journey among the stars of 137 years, we should have seen but a mere atom, just one grain of the works of Him who knows the number of the hairs of our heads, and without whom a sparrow doth not fall to the ground!
Suppose we now inquire, What is the comet's probable business in coming amongst us once in 137 years? Are its duties those of a messenger or a scavenger, or both? It is well known that the sun is continually giving off light and heat, and consequently it must of necessity be gradually exhausting itself. It has been computed that were the mass of the sun composed of Newcastle coal, with exhaustion going on at the present rate, the whole mass would be burnt out in 25,000 years. If the sun, then, is gradually being exhausted by giving off light and heat to his family of planets, and if the planets cannot give any portion of it back to him, seeing that they are entirely dependent upon the sun for their own physical and material existence—how is the sun's strength to be kept up so as to be equal to the demands made upon him?