Passage
One difficulty in relying on early reports of scientific discoveries is that they frequently perpetuate misconceptions—sometimes magnified, sometimes distorted, sometimes entirely fictitious—and, even when partly accurate, they obscure the careful corrections of later inquiry. Such has been the fate of most readers with regard to the first telescopic observations of Mars. There was little precision in the reports of its earliest observers. Struck by a vision so strange and apparently unique, imagination easily outstripped judgment and gave rise to notions which have long since misled expectation.
In 1877 the Italian astronomer Giovanni Schiaparelli announced the discovery of "canali" (canals) on the Martian surface, and described them in terms that fired the imagination of the age. These straight lines, as he drew them, suggested artificial works on a planetary scale. By the end of the century, Percival Lowell in America had expanded these observations into an elaborate theory, claiming Mars to be a world traversed by immense irrigation channels, constructed by an intelligent race struggling against planetary desiccation. Popular books and illustrations made the planet appear the seat of a vast and mysterious civilization.
Yet more precise observations in the early twentieth century gradually swept these notions aside. With more powerful instruments, astronomers concluded that the so-called canals were largely optical illusions, arising from the tendency of the human eye to connect scattered markings by straight lines. Photographic records confirmed the absence of any artificial network. As for the belief that Mars must resound with evidence of an advanced intelligence, it is now seen to be extravagant. What Mars has revealed, instead, is a silence more striking than any imagined activity: a barren landscape, with neither seas to echo nor forests to diffuse sound, its thin atmosphere incapable of carrying more than the faintest whisper of wind.
