Pessimism curtails it. Density is high; compression peak was passed long ago; generation of new heat has ceased and only radiation is continuing, at the rate of two hundred and fifty million tons a minute, three hundred and sixty thousand million tons a day. If chemically engendered, his warmth has not long to last; a piece of coal is soon burnt out. Though radial transmutation be proceeding, and the loud cannonades of ionization, either is at best an “almost” eternal process; which means nothing, piteous nothing. The meteors are paltry helpers; if he attracted enough of them to be worth while, his size would continually be increasing; and it is not increasing. Above all he is old; astrophysically provable in the second yellow era. Even were he not dwindling away, the earth would always be getting less of his heat, since ever receding from him into the cold outer distance.
Leave all such hopes and counter-hopes. Leave aside the sunspots and other such famous regions of solar controversy. Leave out of account the respective chances of his entering a colder corner of the universe or a warmer—look away altogether from the sun himself. Look back to the earth, or beyond to the stars.
Chronometrically classified by spectral seniority, the stars are known by their age. Like man they pass through seven ages, passing from one to the next with as much choice or chance of rebellion as has he. Whether the sun’s epoch be that of early middle-age or late, the difference is at most between a very little more than half his course to run or a very little less. The whole course must be run, till the seventh age and last.
That the earth was once warmer than now, there is persuasive testimony. Despite cyclical reversions, such as the present warm spell following the last ice age, and even though the ice ages be not caused, or not chiefly caused, by diminution in the solar heat but by this or that wayward difference of ellipticity in the earth’s own orbit or whatnot else—even so, the line of the thermic graph is in the long run always downward. After each glacial era the warm reaction is less warm than the time before. The lull after the Cambrian Ice Age was out of comparison warmer than this. There were no deciduous trees. Could the Coal Forests flourish in South Wales or North France today? Could the reptiles now stretch from pole to pole? As late as the warm centuries after the last ice age but one, no permanent snow and ice remained; the polar caps are brand-new. If Arctic fossils are found embedded in what are now warmer climes, as the famous reindeer of Southern France, tropical fauna and flora are far oftener found in what are now colder regions. The primates, we and the monkeys, originated in the Arctic Circle; Peary found Eden. Greenland was once green; amid her Icy Mountains did not the breadfruit trees once wave? Were not the London tubes, a few yards below our streets, cut through clay that enclosed great tropical shells? Does not the Southern Railway, as it crawls over Kent, but piously emulate its predecessors there, the crocodiles? In Paradise—
Si plain de joye et de solas
Que nus n’y puet devenir las—
did not the sun, as Adam long afterwards told Seth, shine daily, all day, deliciously? In the Golden Age was not the world warmer and lovelier, while happiness stretched to the far north? Then the flight from the Poles began. It will continue till we huddle on the Equator.
Man will fight his fate. He will adapt himself. Even today he can survive in parts of Siberia that in January are no warmer than the moon. He will adapt nature; will learn to utilize the earth’s internal heat, if need be moving underground to become a cave-dweller again, and to economize the sun’s. His industries, by chance and then deliberately, will increase the amount of carbonic gas in the air, and so help the latter to retain heat, increase heat, and distribute it more evenly. Heat thus eked out with a hundred strange inventions, light he will learn to dispense with. In ways we cannot conceive of, any more than the mole or the mastodon could conceive of ours, our descendant race, if still on the planet millions of years from now—Man let us still proudly dub him—will be fighting for his life; every secret of terrible science, every trick of his terrified brain, will be called into play to hold up, perhaps for ages, the inevitable end.
Inevitable. As the sun’s light and warmth grow less, the means of artificially conserving them will grow more complicated, and after a while less efficient. By when, despite all strugglings, all undreamt marvels, all delays, the temperature must have fallen by forty or fifty degrees everywhere, earth will have changed from anything we can imagine, will have dwindled to a belt of Equatorial Eskimos white-girdling the icebound tropics. Dimness of anguish; dayfall of the world. God will have fulfilled His grim promises: He will have darkened the sun in his going forth, He will have made their vintage shouting to cease.
Down by sixty or seventy, there will be no life more; and earth a bleak charnel-house, a whited sepulchre. The oceans, if still existent, will be of ice; the clouds, if still any, will be of snow. No wind, no warmth, no rain; no flesh wherein is the breath of life. The cold and the darkness.
The last man will have lain long
