The Earth no longer existed, nor her celestial companion, the little isle of Mars, nor the beautiful sphere of Venus, nor the colossal world of Jupiter, nor the strange universe of Saturn, which had lost its rings, nor the slow-moving Uranus and Neptune—not even the glorious Sun, in whose fecundating heat these mansions of the heavens had basked for so many centuries. The Sun was a dark ball, the planets also; and still this invisible system sped on in the glacial cold of starry space. So far as life is concerned, all these worlds were dead, did not exist. They survived their past history like the ruins of the dead cities of Assyria which the archaeologist uncovers in the desert, moving on their way in darkness through the invisible and the unknown.
No genius, no magician could recall the vanished past, when the Earth floated bathed in light, with its broad green fields waking to the morning sun, its rivers winding like long serpents through the verdant meadows, its woods alive with the songs of birds, its forests filled with deep and mysterious shadows, its seas heaving with the tides or roaring in the tempest, its mountain slopes furrowed with rushing streams and cascades, its gardens enameled with flowers, its nests of birds and cradles of children, and its toiling population, whose activity had transformed it and who lived so joyously a life perpetuated by the delights of an endless love. All this happiness seemed eternal. What has become of those mornings and evenings, of those flowers and those lovers, of that light and perfume, of those harmonies and joys, of those beauties and dreams? All is dead, has disappeared in the darkness of night.
The world dead, all the planets dead, the Sun extinguished. The solar system annihilated, time itself suspended.
Time lapses into eternity. But eternity remains, and time is born again.
Before the existence of the Earth, throughout an eternity, suns and worlds existed, peopled with beings like ourselves. Millions of years before the Earth was, they were. The past of the universe has been as brilliant as the present, the future will be as the past, the present is of no importance.
In examining the past history of the Earth, we might go back to a time when our planet shone in space, a veritable sun, appearing as Jupiter and Saturn do now, shrouded in a dense atmosphere charged with warm vapors; and we might follow all its transformations down to the period of man. We have seen that when its heat was entirely dissipated, its waters absorbed, the aqueous vapor of its atmosphere gone, and this atmosphere itself more or less absorbed, our planet must have presented the appearance of those great lunar deserts seen through the telescope (with certain differences due to the action of causes peculiar to the Earth), with its final geographical configurations, its dried-up shores and watercourses, a planetary corpse, a dead and frozen world. It still bears, however, within its bosom an unexpended energy—that of its motion of translation about the Sun, an energy which, transformed into heat by the sudden destruction of its motion, would suffice to melt it and to reduce it, in part, to a state of vapor, thus inaugurating a new epoch; but for an instant only, for, if this motion of translation were destroyed, the Earth would fall into the Sun and its independent existence would come to an end. If suddenly arrested it would move in a straight line toward the Sun, with an increasing velocity, and reach the Sun in sixty-five days; were its motion gradually arrested, it would move in a spiral, to be swallowed up, at last, in the central luminary.
The entire history of terrestrial life is before our eyes. It has its commencement and its end; and its duration, however many the centuries which compose it, is preceded and followed by eternity—is, indeed, but a single instant lost in eternity.
For a long time after the Earth had ceased to be the abode of life, the colossal worlds of Jupiter and Saturn, passing more slowly from their solar to their planetary stage, reigned in their turn among the planets, with the splendor of a vitality incomparably superior to that of our Earth. But they, also, waxed old and descended into the night of the tomb.
Χ
Had the Earth, like Jupiter, for example, retained long enough the elements of life, death would have come only with the extinction of the Sun. But the length of the life of a world is proportional to its size and its elements of vitality.
The solar heat is due to two principal causes—the condensation of the original nebula, and the fall of meteorites. According to the best established calculations of thermodynamics, the former has produced a quantity of heat eighteen million times greater than that which the Sun radiates yearly, supposing the original nebula was cold, which there is no reason to believe was the case. It is, therefore, certain that the solar temperature produced by this condensation far exceeded the above. If condensation continues, the radiation of heat may go on for centuries without loss.
The heat emitted every second is equal to that which would result from the combustion of eleven quadrillions six hundred thousand milliards of tons of coal burning at once! The Earth intercepts only one five hundredth millionth part of the radiant heat, and this one five hundredth millionth suffices to maintain all terrestrial life. Of sixty-seven millions of light and heat
