THE EVOLUTION OF WORLDS
CHAPTER I
BIRTH OF A SOLAR SYSTEM
ASTRONOMY is usually thought of as the study of the bodies visible in the sky. And such it largely is when the present state of the universe alone is considered. But when we attempt to peer into its past and to foresee its future, we find ourselves facing a new side of the heavens—the contemplation of the invisible there. For in the evolution of worlds not simply must the processes be followed by the mind's eye, so short the span of human life, but they begin and end in what we cannot see. What the solar system sprang from, and what it will eventually become, is alike matter devoid of light. Out of darkness into darkness again: such are the bourns of cosmic action.
The stars are suns; past, present, or potential. Each of those diamond points we mark studding the heavens on a winter's night are globes comparable with, and in many cases greatly excelling, our own ruler of the day. The telescope discloses myriads more. Yet
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