We see nothing in the nature of a beginning or an end
for the totality of worlds, the universe. The life of all living
things on the earth, from the formation of the primitive microbes
to the last struggles of the superman, is a small episode of that
stupendous drama, a fraction of a single scene. But our ampler
knowledge of it, and our personal interest in it, magnify that
episode, and we turn from the cosmic picture to study the
formation of the earth and the rise of its living population.
CHAPTER IV. THE PREPARATION OF THE EARTH
The story of the evolution of our solar system is, it will now be
seen, a local instance of the great cosmic process we have
studied in the last chapter. We may take one of the small spiral
nebulae that abound in the heavens as an illustration of the
first stage. If a still earlier stage is demanded, we may suppose
that some previous sun collided with, or approached too closely,
another mighty body, and belched out a large part of its contents
in mighty volcanic outpours. Mathematical reasoning can show that
this erupted material would gather into a spiral nebula; but, as
mathematical calculations cannot be given here, and are less safe
than astronomical facts, we will be content to see the early
shape of our solar system in a relatively small spiral nebula,
its outermost arm stretching far beyond the present orbit of
Neptune, and its great nucleus being our present sun in more
diffused form.
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