In 1877, the Italian astronomer Giovanni Schiaparelli was planning to observe Mars with a newly powerful refractor telescope installed in Brera, Milan. He prepared extensively, avoiding, he wrote, "everything which could affect the nervous system, from narcotics to alcohol, and especially from the abuse of coffee, which I found to be exceedingly prejudicial to the accuracy of observation." When his resolutely non-shaking hands maneuvered the telescope into place, what he saw were deep trenches meandering across the red planet's surface, which he called "canali."
Hysteria over Mars has reached a breaking point over the past few months as NASA's Curiosity rover beams back breathtaking photos to Earth. NASA already announced a new, "smarter" sequel to Curiosity to launch in 2020, and a press conference has revealed details about actual flowing salt water on Mars's surface, hinting at the possibility of alien life. But mass speculation over Mars's habitability, and indeed its potential for watery canals, has its roots before we ever made it close to the planet, back in Schiaparelli's 19th century.
As Earth's galactic neighbor, Mars was already attracting scientific attention. In 1719, Giacomo Filippo Maraldi noticed that the planet had seasons, which William Herschel confirmed in 1783. In the 1860s, French astronomer Emmanuel Liais guessed (incorrectly) that the variations in Mars's surface over time were due to changing vegetation. But 1877 brought a banner year for Mars watchers because the planet moved into "opposition"—the interplanetary event when Mars, Earth, and the Sun all line up and the distance between the Earth and Mars is the shortest.
Advances in telescope technology accompanied the lucky opposition, allowing Giovanni Schiaparelli and his colleagues to complete their close-up observations and incite an enduring kind of Mars fever. That same year, on August 17, the American astronomer Asaph Hall confirmed the existence of Mars's moons, naming them Deimos and Phobos, or Fear and Terror, after the mythical horses that pulled the chariot of Ares, the Greek god of war, colleague to Mars's namesake, the Roman violent deity.
Hall's discoveries have passed relatively unaltered into the present day, but Schiaparelli's went viral, one might say, after a mistranslation. Instead of its literal meaning of marks or grooves, "canali" in English became "canals," suggestive of water, life, and intelligent intervention in the Martian landscape.
It must be said that Schiaparelli's own map of Mars's surface trenches resembles nothing more than a map of Venice, with river-like tendrils running through and around masses of land that call to mind cities and ports, a living geography. The uncanny design made the possibility of misinterpretation a little easier—which is exactly what happened.
The American astronomer Percival Lowell picked up on Schiaparelli's work, commencing to do more than any one other individual in popularizing the idea that Mars held life. A wealthy man, Lowell decided to build his own observatory for the specific purpose of studying Mars's canals in Flagstaff, Arizona, where visibility was clearest. Lowell's observations were as accurate as they could be for their time, but his enthusiastic interpretation of the canals as Martian constructions alienated his assistants and annoyed Schiaparelli himself.
An1898 article in The Atlantic Monthly summing up the findings of Schiaparelli, Lowell, and others, noted that Mars might be in "an advanced stage of evolution" compared to Earth, at a later stage in its lifespan as a planet. Might this theory also have lent credence to the idea that Mars was hospitable to life, if not at present than perhaps millions of years ago?
In 1906, Lowell published a popular book, Mars and Its Canals, proposing that the canals served to transport water from the poles to the planet's more arid central plains. They were proof of aliens that were not just intelligent, but even smarter than we Earthlings. "A mind of no mean order would seem to have presided over the system we see—a mind certainly of considerably more comprehensiveness than that which presides over the various department of our own public works," Lowell wrote.
The next decades of research didn't bear out his hypothesis, however. In 1907, Is Mars Habitable? by A.R. Wallace directly critiqued Lowell's book, "furnishing a quite natural explanation of features of the planet which have been termed 'non-natural' by Mr. Lowell," as Wallace writes in theintroduction.
Despite the debunking, by 1938, Orson Welles took Mars fever and amplified it with the radio drama War of the Worlds, which riffed on the possibilities of the canals. The play's radio host asks a scientist what Mars's surface striations are. "Not canals, I can assure you, Mr. Phillips, although that's the popular conjecture of those who imagine Mars to be inhabited," the scientist says. Of course, this particular fictional scientist was proven wrong by the sudden arrival of Martian shock troops on Earth to mount an invasion, as Welles's story led innocent listeners to believe. Fear and terror—Deimos and Phobos—indeed.
In popular films (especially as depicted on their attendant posters), Mars then became a dry, red, craggy landscape populated only by malevolent aliens bent on fighting humans. The composite image seems far from what Lowell would have imagined as the watery, productive, developed society of the planet.
The various misinterpretations and curveballs of Mars's gradual discovery came to a more certain conclusion with NASA'sViking program in the 1970s. We could finally see what its surface actually held. The truth was closer to the movies—desiccated, cratered, not a river or canal in sight.
Despite the unveiling, Mars fever continues unabated into the present. It might just be that we underestimated the past legacy of Mars science. With the news of liquid salt water on the planet's surface, Lowell's once-reviled theories come back to mind. His theories of an advanced civilization in decline may have been wrong, but there is water flowing on Mars. The question becomes: what are we misunderstanding now about the red planet?
