When Earth was thought to lie at the centre of the universe, the planets were seen as wandering stars – Gods perhaps, or their distant abodes. Once Copernicus, Galileo and Kepler redrew the solar system, however, Earth became the paradigm for planetary interpretation. Now it became possible to ask whether Mars and other wanderers might have mountains and oceans, and whether they might support life, even civilizations. Indeed, as Earth was the model, intelligence was more or less the expectation for alien life. A verse in Milton’s Paradise Lost captures this new perspective well, “Witness this new-made World . . . with stars numerous, and every star perhaps a world of destined habitation”. Scientific mapping of Mars began around 1840. By 1877, Nathaniel Green, a British astronomer, had produced a lovely set of maps compiled from the observations of many colleagues. Green’s painterly embrace of diffuse lines and pastel shades – darker in the northern hemisphere and lighter in the south, with white caps at the poles – communicates clearly the limits of nineteenth-century observation. Within a year, however, Green’s masterpiece had been eclipsed by a new map from the Italian astronomer Giovanni Schiaparelli. Where Green had artfully conveyed uncertainty, Schiaparelli drew a sharply detailed landscape dissected by broad “canali”, or channels.
more from Andrew H. Knoll at the TLS here.