In 1877, Italian astronomer Giovanni Schiaparelli turned his 21.8-centimetre telescope – one of the finest of the time – on the enigmatic disk of Mars.
Scientists had long known that rather than simply being a point of light in the sky Mars was an entire world unto itself, but Schiaparelli was the first to attempt to map it in detail.
He observed dark areas, which he presumed to be seas, connected by linear features hundreds of kilometres long. He dubbed the latter canali, a term that technically means channels, but was translated into English as “canals.”
In the 1870s and ’80s, Schiaparelli mapped Mars again and again, convincing himself that the canal system was rapidly expanding – much as if an advanced civilisation were desperately trying to preserve its water supply in the face of drought.
Even at the time, many of Schiaparelli’s colleagues were dubious, wondering, in the words of US astronomer David Weintraub in his 2018 book Life on Mars (Princeton University Press), whether these features were simply “the result either of bad optics in Schiaparelli’s telescope or in his own head.”
But Schiaparelli’s vision captured the public imagination. Others would even suggest that the Red Planet’s colour was due to ruddy vegetation, much as if it were covered in Japanese maples. In 1938, Orson Welles’ radio adaptation of War of the Worlds panicked hundreds of thousands of listeners, convincing them that death-dealing Martian “tripods” were on the verge of showing up at their doorsteps.