“A Mysterious System of Configurations:” The Environmental History of Canals and Climate on Mars

• In Event: The Final Frontier (of Environmental History): Interdisciplinary Perspectives on Environments Beyond Earth

Abstract

Over the course of the seventeenth and eighteenth centuries, Mars in the European and North American imagination was transformed from a point of light into a world like our own. By the late eighteenth century, astronomers realized that this new world had a complex environment that seemed at once familiar and puzzling. Over the course of the nineteenth century, astronomers used ever more sophisticated telescopes to discover that the planet’s environment could change dramatically. This paper draws on the methods of climate history to explain these environmental changes, and to trace how they provoked influential new impressions of the Red Planet among scientists and the European public.

Such impressions were actually the product of two atmospheres. Shifting conditions in Earth's atmosphere either blurred or greatly clarified the features that could be observed through contemporary telescopes. Changes in the Martian atmosphere, meanwhile, unveiled the Martian surface, presented strange new phenomena, or occasionally obscured all detail. Interactions between these atmospheres sometimes revealed environmental changes on Mars that led some scientists to conclude that the Red Planet must be inhabited by intelligent life. Martian weather and climate encouraged the illusion of Martian “canals,” and even suggested reasons for the construction of such canals.

The case for intelligent Martians faltered in the early twentieth century. Scientists using more powerful telescopes could not discern canals on the Martian surface, but they could conclude that the Martian atmosphere was largely unsuited to life. Eventually, that atmosphere came to be regarded as a worrisome foreshadowing of what might someday happen to Earth. But all was not lost: fresh debates started about whether it would be possible to restore the Martian atmosphere so that it could accommodate human colonization.

Author

• Dagomar Degroot, Georgetown University