Extraterrestrial Civilizations Read Online Free PDF Page B

full circle of light, then waned to a crescent and died. Each new Moon was literally a
new
Moon, a fresh creation.
    Quite early on, however, it became apparent that the horns of the lunar crescent
always
faced away from the Sun. That alone was sufficient to indicate some connection between the Sun and Moon’s phases. Once the notion of that connection arose, further observation would show that the phases were connected with the relative positions of the Sun and Moon. The Moon was full when it and the Sun were at precisely opposite parts of the sky. The Moon was in the half-phasewhen it and the Sun were separated by 90 degrees. The Moon was in crescent shape when it was close to the Sun, and so on.
    It became apparent that if the Moon were a sphere that was as dark as the Earth, and if the Moon shone only by the light that fell upon it from the Sun and was reflected by it, then it would go through precisely the cycle of phases that were actually observed. The idea arose and grew to be more and more accepted that the Moon, at least, was a dark body like Earth and was not composed of blazing “aether.”
ANOTHER WORLD
    If the Moon were like the Earth in being dark, might it not be like the Earth in other ways? Might it not be a second world?
    As early as the fifth century B.C ., the Greek philosopher Anaxagoras (500–428 B.C .) expressed his opinion that the Moon was an Earthlike world.
    To imagine the Universe as consisting of one world plus bits of light is intellectually acceptable. To imagine it to consist of two worlds plus bits of light is difficult. If one of the objects in the sky is a world, why not some or all the rest? Gradually, the notion of the plurality of worlds spread. Increasing numbers of people began to think of the Universe as containing many worlds.
    But not
empty
worlds. That thought apparently filled people with revulsion—if it occurred to them at all.
    The one world we know—Earth—is full of life, and it is only natural to think that life is as inevitable a characteristic of worlds generally as solidity is. Again, if one thinks of the Earth as having been created by some deity or deities, then it is logical to suppose the other worlds to have been so created as well. It would then seem nonsensical to suppose that any world would be created and left empty. What motivation could there be in creating empty worlds? What a waste it would be!
    Thus, when Anaxagoras stated his belief that the Moon was an Earthlike world, he also suggested that it might be inhabited. So did other ancient thinkers, as for instance the Greek biographer Plutarch ( A.D . 46–120).
    Then, again, if a world is inhabited, it seems natural to supposeit to be inhabited by intelligent creatures—usually pictured as very much like human beings. To suppose a world to be inhabited only by unreasoning plants and animals would, again, seem to represent an intolerable waste.
    Oddly enough, there was talk of life on the Moon even before the Moon was recognized as a world. This arose out of the fact that the Moon is again unique among heavenly bodies in not being evenly shining. There are darker smudges against the bright light of the Moon, smudges that are most clearly and dramatically visible at the time of the full Moon.
    It was tempting for the average unsophisticated observer of the Moon to try to make a picture out of the smudges upon its face. (In fact, even the sophisticated and knowledgeable present-day observer may be tempted to do so.)
    Given the natural anthropocentricity of human beings, it was almost inevitable that those smudges were pictured as representing a human being, and the notion of the “man in the Moon” arose.
    Undoubtedly the original notion was prehistoric. In medieval times, however, attempts were often made to clothe age-old notions with a cloak of Biblical respectability. Therefore, the man in the Moon was thought to represent the man mentioned in Numbers 15:32–36: “And while the children of Israel