Setting the record straight on the canals of Mars

There’s an old story that I’ve heard several times about how Mars came to be associated with its famous canal imagery that goes something like this:

During Mars’s “Great Opposition” of 1877, Italian astronomer Giovanni Schiaperelli observed a dense network of linear structures on the surface of Mars which he called “canali” in Italian, meaning “channels” but the term was mistranslated into English as “canals”.

While the term “canals” indicates an artificial construction, the term “channels” connotes that the observed features were natural configurations of the planetary surface. From the incorrect translation into the term “canals”, various assumptions were made about life on Mars; as these assumptions were popularized, the “canals” of Mars became famous, giving rise to waves of hypotheses, speculation, and folklore about the possibility of intelligent life on Mars, the Martians. Among the most fervent supporters of the artificial-canal hypothesis was the American astronomer Percival Lowell, who spent much of his life trying to prove the existence of intelligent life on the red planet.

That quote above is (with minor edits) taken from Schiaperelli’s Wikipedia page, but I’ve seen the story told more or less in this form in lots of other places. But there are big problems with this telling, and primary among them is this idea that a simple mistranslation is entirely or even largely responsible for popularizing the Martian canals.

Today, we know there are no canals on Mars. Their existence had been doubted by some scientists for decades, and the Mariner 4 flyby of Mars in 1965 put the matter conclusively to rest.

But here’s a stumper for you: What did Schiaperelli see on the Martian surface that warranted the name “canali”? And what did Lowell see to make him so certain that man-made canals existed that he wrote three books on the subject between 1895 and 1908?

Because let’s face it — Lowell was no second-hand scientist. The idea of a habitable Mars criss-crossed by canals got Lowell so excited that he built an observatory in the high desert near Flagstaff, Arizona, precisely so he could get better views of the red planet and confirm those observations. And he did confirm them.

Lowell spent years recording his observations of Mars, even going so far as to classify the canals into different types and to draw maps of their position on the planet’s surface. At times, Lowell even claimed that he saw measurable differences in their lengths between observations, clear evidence in his mind of ongoing construction by the inhabitants of Mars.

In other words, Lowell’s certitude about the artificial nature of the Martian canals was based on his own direct observation — not on some sloppy Italian-to-English translation. If his Flagstaff observatory hadn’t yielded ample canal-related observations, then the issue very well would have been dead back in 1895.

This is doubly the case since Lowell’s fascination with Mars began after reading the works of Camille Flammarion, a French astronomer who wouldn’t have been tripped up by the fabled translation error that supposedly hoodwinked the English-speaking world.

Flammarion’s ideas about the planets were extremely influential during the end of the 19th century, and are still fascinating to read today as works of free-wheeling speculation and flights of fanciful logic. Unfortunately, I haven’t been able to read the particular book that fired Lowell’s imagination (La plan√®te Mars et ses conditions d’habitabilit√©, 1892), since much of Flammarion’s work isn’t freely available in English.

But suffice to say that Flammarion believed that planets all went through more or less the same stages of development, but at different rates depending on their sizes. Thus, the small Moon was a dead Earth — its water evaporated, its atmosphere scoured away, and its inhabitants long expired (unless they survived in deep valleys). Jupiter, on the other hand, was a collapsing sun and an “Earth-to-be” — a world that would condense itself down to a rocky core and attain an Earth-like state favorable to life thousands or millions of years in the future.

In Flammarion’s view, Mars lay on this developmental axis somewhere between the Moon and Earth. Mars was drying up, losing its water and atmosphere, but was perhaps not quite dead yet. In this context, it only made sense that the canals observed by Schiaperelli might be the last gasp of a dying civilization, attempting to shift water from the shrinking poles and oceans to the habitable zones where their cities were built.

If you’re getting shades of Barsoom from all of this, that’s because Flammarion’s ideas heavily influenced Edgar Rice Burroughs’s concept of Mars. Other early science-fiction writers were equally inspired in other ways. George Griffith refers to Flammarion constantly in his round-the-solar-system planetary romance A Honeymoon in Space (1901) and William Hope Hodgson’s vision of a dying Earth in The Night Land (1912) has a lot in common with some of the astronomer’s ideas. Flammarion himself even wrote science-fiction, such as the end-of-the-world story La Fin du Monde (1893), which is available in English from the University of Nebraska Press under the title Omega.

The point of all this is that Percival Lowell was not alone in his beliefs and that his beliefs were not based on a mistranslation. Schiaperelli’s word choice probably didn’t help things, but if a translation error was at the root of all this, then the mistake would have been definitively corrected sometime in the forty years between the original observations and Lowell’s death in 1916.

So what were all those astronomers seeing on the surface of Mars? What were the canals after all? Multiple reliable observers working from different observatories reported perfectly straight channels that were up to thousands of miles long. Not everyone believed the channels were man-made (or Martian-made), but their existence wasn’t controversial.

In fact, an astronomer named Alfred Russel Wallace published a point-by-point book-length takedown of Lowell’s theories of artificial construction in 1907. To Wallace, the sheer size and impracticality of the canals (as well as the speed with which some of them were apparently constructed) argued against any intelligent agency being behind them. But Wallace didn’t dispute the existence of the channels, or even the physical features that Lowell and others described. He simply didn’t buy their theories of how they came to be, and instead believed they were the result of natural forces.

The first scientist to noodle out the correct explanation was another Italian astronomer named Vincenzo Cerulli, who proposed that the “canali” — whether “canals” or “channels” — were optical illusions. That theory was finally confirmed when the Mariner probes of the 1960s returned close-up pictures of Mars that showed no trace of the channels.

For me, the mystery that remains is why this fixation on the mistranslation of Schiaperelli’s word persists. It’s true that Schiaperelli didn’t necessarily intend for his “canali” to be considered the work of intelligent beings. But do people who repeat this story imagine that Flammarion, Lowell, Wallace, and others were such dupes that they never stopped to question the implications of this single word? If the translation of Schiaperelli’s work had read “railroad tracks” instead of “canals”, do these people imagine that the scientific community would have blithely accepted that claim without checking it?

These men were scientists, given to asking questions and seeking truth, and all of them were wrong in different ways. Schiaperelli, through no fault except the inadequacy of his instruments, saw something that wasn’t there. Meanwhile, Flammarion’s desire for a unified planetary theory led him to extrapolate some truly majestic errors from the scant information available to him.

Later, Lowell and Wallace found themselves lobbing whole books at each other from opposite sides of a scientific debate that was founded on an optical illusion. In hindsight, it seems like the awesome scope and weirdness of the features they were arguing about should have been some kind of tip-off. But for those two, it wasn’t. They were too wrapped up in the details of the debate to see the novel solution that solved everything.

This story, to me, is way more interesting than the story about the mistranslation. It’s a cautionary tale about believing what you see even when it doesn’t make sense, about letting a desire for elegance run away with you, and about being so blinded by preconceptions that your better judgment takes a permanent vacation.

Of course, science sometimes needs crazy theories to shake new ideas loose. I suspect there were those who considered Cerulli’s optical illusion theory pretty crazy. So if anyone is at fault here, it’s not because they were thinking up bold new theories in a fact-poor environment. Instead, the fault comes with failing to adequately differentiate between facts and hypotheses, and in becoming so attached to a pre-existing theory that it can’t be shaken loose even when excellent arguments are made against it.


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