"As there are other globes like our earth," says a popular author, "so, too, there are other worlds like our solar system. There are self-luminous suns exceeding in number all computation. The dimensions of the earth pass into nothingness in comparison with the dimensions of the solar system, and that system, in its turn, is only an invisible point if placed in relation with the countless hosts of other systems which form, with it, clusters of stars. Our solar system, far from being alone in the universe, is only one of an extensive brotherhood, bound by common laws and subject to like influences. Even on the very verge of creation, where imagination might lay the beginning of the realms of chaos, we see unbounded proofs of order, a regularity in the arrangement of inanimate things, suggesting to us that there are other intellectual creatures like us, the tenants of those islands in the abysses of space.
"Though it may take a beam of light a million years[[20]] to bring to our view those distant worlds, the end is not yet. Far away in the depths of space we catch the faint gleams of other groups of stars like our own. The finger of a man can hide them in their remoteness. Their vast distances from one another have dwindled into nothing. They and their movements have lost all individuality; the innumerable suns of which they are composed blend all their collected light into one pale milky glow.
"Thus extending our view from the earth to the solar system, from the solar system to the expanse of the group of stars to which we belong, we behold a series of gigantic nebula creations rising up one after another, and forming greater and greater colonies of worlds. No numbers can express them, for they make the firmament a haze of stars. Uniformity, even though it be the uniformity of magnificence, tires at last, and we abandon the survey, for our eyes can only behold a boundless prospect, and conscience tells us our own unspeakable insignificance!"[[21]]
That philosophy which considered the earth to be the immovable centre of the universe with sun, moon and stars performing a daily revolution about it was not more erroneous than that which asserted the earth and the universe to be instantaneously created about six thousand years ago, out of nothing.
The doctrine that the earth and universe were created out of nothing, need not detain us a moment. The absurdity of such a proposition is self-evident, and is becoming quite generally conceded.
Of the idea that the earth and the heavens, by which I understand is meant the universe, were created about six thousand years ago, it is only necessary to say that the discoveries men made in astronomy led them to question the correctness of that theory. Men have learned that there is a progressive movement in light. That is, the rays of light emitted by an object, "and making us sensible of its presence by impinging on the eye, do not reach us instantaneously, but consume a certain period in their passage. If any sudden visible effect took place in the sun, we would not see it at the absolute moment of its occurrence, but about eight minutes later, this being the time required for light to cross the intervening distance."[[22]] It is said by astronomers that there are objects in the heavens so distant that it would take many hundreds of thousands of years—allowing that light travels at the rate of 198,000 miles per second—for their light to reach us; and since we see them it necessarily follows that they have existed so long. They, at least, were not created six thousand years ago, but long before that time. If the orthodox theory was wrong as to the time when those distant worlds were created, may it not be equally wrong concerning the age of the earth?
Of course, it cannot be expected that in this work the writer can give any extended review of the evidence which geology furnishes of the great age of the earth. It will be enough to say that when men look upon the earth, and take note of those forces which today are producing the gradual changes in the structure of its islands, continents, mountain ranges and deltas, and then attribute the changes which have evidently taken place in the past to the operation of those same forces, they see on all sides of them evidences of a very great antiquity for the origin of the earth.
It is generally conceded that all the heat we now have upon the surface of the earth comes from the sun; but this only effects the surface of the earth to the extent of a few feet at most. It has been determined, however, by experiments so many times repeated, and in all parts of the earth that it cannot be attributed to any merely local cause, that beyond the few feet of the earth's surface affected by the sun's heat, a stratum of invariable temperature is discovered, beneath which as we descend, the heat increases at the uniform rate of one degree Fahrenheit for every fifty or seventy feet. The uniformity of this rate implies that at no great depth a very high temperature must exist. "We have every reason to believe," remarks Newcomb, "that the increase of say one hundred degrees a mile continues many miles into the interior of the earth. Then we shall have a red heat at a distance of twelve miles, while at the depth of one hundred miles the temperature will be so high as to melt most of the materials which form the solid crust of the globe."[[23]]
The globular form of the earth is also looked upon as evidence of its original fluidity; while the existence of volcanoes, found all over the land, as well in the frigid as the torrid zone; in ocean beds as well as in the interior of continents, proving that they are not merely local, or depend on restricted areas for the liquid lava they belch forth—are supposed to furnish indisputable evidence that the interior of the earth is now as its whole mass once was, white-hot, molten matter.
Granting that the whole earth was once such a ball of fire, the time for the cooling of such a mass to the present depth of the earth's crust would require a much longer period than the sometime orthodox view of the Bible account of creation allows. "The age of the earth," remarks Draper, "is not a question of authority, not a question of tradition, but a mathematical problem sharply defined; to determine the time of cooling a globe of known diameter, and of given conductibility by radiation in a vacuum."