As a result, there was an early general acceptance that intersecting lines on Mars were real features in the Martian landscape, rather than optical illusions or visual disturbances.

Astronomers struggled, however, to interpret the unexpected patterns they perceived on Mars. The lines did not look like anything that could have been produced by natural geological or geomorphological processes, given that the spokes appeared to be unwaveringly straight over thousands of miles, with an unlikely number of straight lines meeting at perfectly round intersections. This curiosity raised the question of whether intelligent beings were responsible for modifying the planet’s surface, either through agriculture, engineering, or some unknown activity. As astronomers pondered this likelihood, an influential explanation was put forward in the 1890s suggesting that the lines and patterns could be a system of irrigation canals used to bring seasonal snowmelt from the polar regions on Mars to the drier tropical and equatorial zones where inhabitants were most likely to reside. [3]

Today, we believe that the geometrical appearance observers noted during their nineteenth-century telescope observations was actually an illusory optical effect. At the time, however, the spoke-like patterns were taken at face value, prompting a widespread popular interest in Mars and a serious consideration of the possibility that Mars might be inhabited. [4]

Scientists, science writers and literary commentators responded to astronomers’ astonishing reports in a wide variety of publications: scientific journals, newspapers, public lectures, pamphlets, magazines, books, and serialized fiction. The inhabited-Mars hypothesis was not accepted by everyone, especially not by leading astronomers who cautioned that it would be almost impossible to definitively prove the existence of Martian inhabitants even if they did exist. But the inhabited-Mars hypothesis achieved broad legitimacy with certain audiences, spurring a mania of speculation into the 1910s over what the Martians were like and how to communicate with them. A number of works were written about Martian irrigation, focusing on topics from the inevitability of landscape and climate change, to the promise of environmental engineering and the possibility of global social organization. In hindsight, it is unsurprising that these topics were of high interest to mainstream readers in both Europe and North America, regions that had deep theoretical and practical interests in how these same issues might influence their imperial and expansionist activities around Earth’s globe. [5]