Extraterrestrial Civilizations by Isaac Asimov Read Free Book Online Page B

fiction without actually saying that that was what it was.
    He chose for his subject the expedition of the English astronomer John Herschel (1792–1871). Herschel had gone to Capetown in southern Africa to study the southern sky.
    Herschel had taken good telescopes with him, but they were not the best in the world. Their value lay not in themselves but in the fact that since all astronomers and astronomical observatories were at that time located in the northern hemisphere, the regions near the South Celestial Pole had virtually never been studied at all. Almost any telescope would have been useful.
    Locke knew well how to improve on that. Beginning with the August 25, 1835 issue of the
Sun
, Locke carefully described all sorts of impossible discoveries being made by Herschel with a telescope capable (so Locke said) of such magnification that it could see objects on the Moon’s surface that were only eighteen inches across.
    In the second day’s installment, the surface of the Moon was described. Herschel was said to have seen flowers like poppies and trees like yews and firs. A large lake, with blue water and foaming waves, was described, as were large animals resembling bisons and unicorns.
    One clever note was the description of a fleshy flap across the forehead of the bisonlike creatures, a flap that could be raised or lowered to protect the animal “from the great extremes of light and darkness to which all the inhabitants of our side of the moon are periodically subject.”
    Finally, creatures with human appearance, except for the possession of wings, were described. They seemed to be engaged in conversation: “their gesticulation, more particularly the varied action of their hands and arms, appeared impassioned and emphatic. We hence inferred that they were rational beings.”
    Astronomers, of course, recognized the story to be nonsense, since no telescope then built (or now, either) could see such detail from the surface of the Earth, and since what was described was utterly at odds with what was known about the surface of the Moon and its properties.
    The hoax was revealed as such soon enough, but in the interval the circulation of the
Sun
soared until, for a brief moment, it was the best-selling newspaper in the world. Uncounted thousands of people believed the hoax implicitly and remained eager for more, showing how anxious people were to believe in the matter of extraterrestrial intelligence—and indeed in any dramatic discovery (or purported discovery) that seems to go against the rational but undramatic beliefs of realistic science.
    As the Moon’s deadness became more and more apparent, however, hope remained that this was an unusual and an isolated case; and that the other worlds of the Solar system might be inhabited.
    When the English mathematician William Whewell (1794–1866), in his book
Plurality of Worlds
published in 1853, suggested that some of the planets might not bear life, this definitely represented a minority opinion at the time. In 1862, the young French astronomer Camille Flammarion (1842–1925) wrote
On the Plurality of Habitable Worlds
in refutation, and this second book proved much the more popular.
    Soon after the appearance of Flammarion’s book, however, a new scientific advance placed the odds heavily in Whewell’s favor.
AIRLESSNESS
    In the 1860s, the Scottish mathematician James Clerk Maxwell (1831–1879) and the Austrian physicist Ludwig Edward Boltzmann (1844–1906), working independently, advanced what is called the kinetic theory of gases.
    The theory considered gases as collections of widely spaced molecules moving in random directions and in a broad range of speeds. It showed how the observed behavior of gases under changing conditions of temperature and pressure could be deduced from this.
    One of the consequences of the theory was to show that the average speed of the molecules varied directly with the absolute temperature, and inversely with the square root of the