“Thus the solar heat is changed into air or water currents, into the expansive force of gases and vapors, into electricity, into woods, flowers, fruits and muscular energy. So long as this brilliant star supplies us with sufficient heat the continuance of the world and of life is assured.
“The probable cause of the heat of the sun is the condensation of the nebula in which this central body of our system had its origin. This conversion of mechanical energy must have produced 28,000,000 degrees centigrade. You know gentlemen, that a kilogram of coal, falling from an infinite distance to the sun, would produce, by its impact, six thousand times more heat than by its combustion. At the present rate of radiation, this supply of heat accounts for the emission of thermal energy for a period of 22,000,000 years, and it is probable that the sun has been burning far longer, for there is nothing to prove that the elements of the nebula were absolutely cold; on the contrary they themselves were originally a source of heat. The temperature of this great day-star does not seem to have fallen any; for its condensation is still going on, and it may make good the loss by radiation. Nevertheless, everything has an end. If at some future stage of condensation the sun’s density should equal that of the earth, this condensation would yield a fresh amount of heat sufficient to maintain for 17,000,000 years the same temperature which now sustains terrestrial life, and this period may be prolonged if we admit a diminution in the rate of radiation, a fall of meteorites, or a further condensation resulting in a density greater than that of the earth. But, however far we put off the end, it must come at last. The suns which are extinguished in the heavens, offer so many examples of the fate reserved for our own luminary; and in certain years such tokens of death are numerous.
“But in that long period of seventeen or twenty million years, or more, who can say what the marvellous power of adaptation, which physiology and paleontology have revealed in every variety of animal and vegetable life, may not do for humanity, leading it, step by step, to a state of physical and intellectual perfection as far above ours, as ours is above that of the iguanodon, the stegosaurus and the compsognathus? Who can say that our fossil remains will not appear to our successors as monstrous as those of the dinosaurus? Perhaps the stability of temperature of that future time may make it seem doubtful whether any really intelligent race could have existed in an epoch subjected, as ours is, to such erratic variations of temperature, to the capricious changes of weather which characterize our seasons. And, who knows if before that time some immense cataclysm, some general change may not bury the past in new geological strata and inaugurate new periods, quinquennial, sexennial, differing totally from the preceding ones?
“One thing is certain, that the sun will finally lose its heat; it is condensing and contracting, and its fluidity is decreasing. The time will come when the circulation, which now supplies the photosphere, and makes the central mass a reservoir of radiant energy, will be obstructed and will slacken. The radiation of heat and light will then diminish, and vegetable and animal life will be more and more restricted to the earth’s equatorial regions. When this circulation shall have ceased, the brilliant photosphere will be replaced by a dark opaque crust which will prevent all luminous radiation. The sun will become a dark red ball, then a black one, and night will be perpetual. The moon, which shines only by reflection, will no longer illumine the lonely nights. Our planet will receive no light but that of the stars. The solar heat having vanished, the atmosphere will remain undisturbed, and an absolute calm, unbroken by any breath of air, will reign.
“If the oceans still exist they will be frozen ones, no evaporation will form clouds, no rain will fall, no stream will flow. Perhaps, as has been observed in the case of stars on the eve of extinction, some last flare of the expiring torch, some accidental development of heat, due to the falling in of the sun’s crust, will give us back for a while the old-time sun, but this will only be the precursor of the end; and the earth, a dark ball, a frozen tomb, will continue to revolve about the black sun, travelling through an endless night and hurrying away with all the solar system into the abyss of space. It is to the extinction of the sun that the earth will owe its death, twenty, perhaps forty million years hence.”
The speaker ceased, and was about to leave the platform, when the director of the academy of fine arts begged to be heard:
“Gentlemen,” he said, from his chair, “if I have understood rightly, the end of the world will in any case result from cold, and only several million years hence. If, then, a painter should endeavor to represent the last day, he ought to shroud the earth in ice, and cover it with skeletons.”
A WORLD OF ICE.
“Not exactly,” replied the Columbian chancellor. “It is not cold which produces glaciers,—it is heat.