A Man, a Plan, a Canal—Mars!

In this episode of *99% Invisible*, host Roman Mars interviews science journalist David Barron about his book on the turn-of-the-century craze that convinced much of the Western world that intelligent Martians were real. The central thesis is that one wealthy, stubborn amateur astronomer named Percival Lowell used his family connections, personal fortune, and persuasive rhetoric to sell a grand theory of a dying Martian civilization building planet-wide irrigation canals—and that the public eagerly embraced it because it offered hope during a turbulent era. The conversation moves from the scientific details of how the "canals" were seen (and mis-seen) through primitive telescopes to the broader cultural and psychological forces that made mass delusion possible, drawing clear parallels to modern debates about science, expertise, and truth.

3:13Who Was Percival Lowell?

Percival Lowell came from one of the most prominent families in New England—the Lowells of Massachusetts were incredibly wealthy, major philanthropists, and deeply embedded in Boston's cultural and intellectual life. As the eldest son, he carried enormous weight: his father had told him and his brother they had to do something important with their lives. After graduating from Harvard, Lowell traveled widely and became one of the first Americans to visit Korea, writing a book about it and building a reputation as a roving anthropologist. But as he approached age 40, he decided to become an astronomer—and he had the wealth to do it in a spectacular way.

David Barron describes Lowell as psychologically fascinating: "He clearly had a big ego and a fragile ego." This combination would prove crucial. Lowell wanted to make his mark, and he chose Mars as his canvas. He would go on to become the most famous astronomer in America at that time, not because his science was sound, but because he was articulate, well-connected, and utterly convinced of his own correctness.

4:30The Mystery of the Canals

The 19th century saw major advances in telescope technology, and by the late 1800s astronomers were getting good views of Mars's surface. Earth and Mars come close together only once every 26 months, and about every 15 years they come especially close—the prime time for observation. In 1877, during one such close approach, Italian astronomer Giovanni Schiaparelli created a new map of Mars. The planet looked remarkably Earth-like, with dark areas assumed to be oceans and light areas thought to be continents. But Schiaparelli also saw fine lines crisscrossing the light areas, which he called *canali*—Italian for "channels," implying natural waterways.

This was mistranslated into English as "canals," which carries a very different meaning: something built by intelligent beings. Nobody knew what these straight-looking lines might be. When Percival Lowell decided in 1894 to dedicate himself to astronomy, solving the mystery of the canals became his life's mission.

Lowell developed a coherent theory: Mars was an older planet than Earth, so it had hardened and become habitable earlier. Life on Mars had evolved intelligence before life on Earth, but now the planet was in its dying phases. Mars had polar ice caps, so if intelligent Martians were running out of water, they would need to tap the meltwater and bring it to their cities and farms. The canals, Lowell argued, were a worldwide irrigation network—the engineering achievement of a unified Martian civilization. As Barron notes, "It was a coherent theory that fit with a lot of ideas about Mars at the time that at least was worth investigating." The problem was that Lowell went into it wanting to prove himself right, which is "kind of a mistake in science."

8:13The Difficulty of Seeing Mars

To understand how anyone could believe in Martian canals, you have to forget everything we know about Mars today from high-resolution photos and rovers. In the late 19th century, all anyone knew came from looking through an Earth-bound telescope at a planet 35 million miles away at its closest. Worse, you're looking through Earth's atmosphere—"like looking at the sky from the bottom of an ocean," as Barron puts it. The air distorts light, making the planet wobble and go in and out of focus. Observers got only split-second glimpses of clarity, requiring them to stare for long periods and remember what they saw.

Barron actually visited Lowell Observatory in Flagstaff, Arizona, in 2018, during a close approach of Mars, and looked through Lowell's original telescope. He describes staring at the "apricot colored orb" as hypnotic: "You just stare and stare and stare, and it's sometimes hard to know what you've seen and what you thought you saw, what you imagined you saw." This perceptual ambiguity was the fertile ground where Lowell's theories took root.

Lowell built a state-of-the-art observatory in Flagstaff and hired away Harvard astronomers to staff it. One assistant, Andrew Ellicott Douglas (A.E. Douglas), initially went along with Lowell, seeing and mapping the lines. But when Douglas began to question whether the lines were real or illusory, Lowell summarily fired him. "He did not like to be questioned," Barron observes.

11:09The Debate and the Public Craze

The canals were intensely debated in the scientific community. Astronomers at other observatories with excellent telescopes couldn't see them. Even Schiaparelli said they weren't always visible—you needed the right viewing conditions. To make things more complicated, the lines seemed to come and go with the Martian seasons. But those who saw the canals had a rhetorical advantage: they could dismiss skeptics by saying their eyesight wasn't good enough, their telescope wasn't powerful enough, or their observatory was in a location with bad atmospheric conditions.

Lowell was incredibly articulate and came from a family that gave him platforms. The Lowell Institute in Boston—founded by his cousin and overseen by his father—invited him to give free public lectures at MIT. He published the texts of those talks in the *Atlantic Monthly*, whose founding editor was another relative, James Russell Lowell. From there, the mainstream press took over.

This was the era of Joseph Pulitzer and William Randolph Hearst, who were inventing the tabloid press—then called the "Yellow press." They latched onto anything sensationalistic, and life on Mars fit perfectly. The Pulitzer and Hearst newspapers pushed Lowell's ideas aggressively, propelling the Martian craze into the general populace.

14:19Nikola Tesla and the Peak of the Craze

The craze reached its zenith when Nikola Tesla got involved. In 1899, Tesla was experimenting with wireless transmission (what we now call radio) at a laboratory in Colorado. One night, alone in the lab, he heard a strange signal in his receiver—a repeating pattern of clicks in triplets. Tesla decided there was no natural explanation and announced to the world that Percival Lowell's Martians were sending a signal to Earth. The news exploded.

Barron makes a point of saying that he himself probably would have gotten caught up in the craze, and he explains why. The turn of the century—the Gilded Age—was not the glittering time its name suggests. There was a tremendous divide between the few exceptionally rich and the many desperately poor. Violent labor unrest was common, anarchism was a feared political force, and President William McKinley was assassinated by an anarchist. The world felt like it was falling apart.

Part of Lowell's theory was that the Martians were not only intellectually and technologically advanced but morally superior. A planet-wide irrigation network meant everyone was working together—no warring nations, just a unified civilization pulling together. This was deeply appealing to people who longed for a world with less violence and more cooperation. If we could just get in touch with the Martians, maybe they could solve our problems on Earth.

Remarkably, the idea of intelligent life on Mars did not upend religion or people's sense of self. Theologians and clergy found ways to incorporate it: this was just more worlds, more beings for God to oversee, showing the glory of God to be even greater than imagined. Barron discovered a newspaper article from 1909 that listed "Questions Mars Might Answer"—and they weren't practical questions about canals or flight. They were the most existential questions: What is the meaning of life? What happens to the soul when you die? How can we prevent human suffering?

24:17The Small Boy Theory and the Unraveling

As Lowell's ideas peaked, more traditional astronomers decided it was time to end the madness. One of the most prominent "anti-canalists" was Edward Walter Maunder of the Greenwich Observatory in London. He devised a clever experiment: he took a map of Mars, erased the canals, and replaced them with natural features like meandering rivers and stippling. He hung these depictions at the front of a classroom and had schoolboys draw what they saw from their seats, without telling them it was Mars.

The results were striking. Boys in the front, who could see clearly, drew the natural features accurately. Boys in the back, too far away to see details, left those features out entirely. But boys in the middle—who could see that there were fine features but couldn't make them out—drew straight lines. They were seeing the same optical illusion that astronomers saw when looking at Mars at the limits of perception.

Lowell derisively called this the "Small Boy theory" of the lines on Mars, arguing that an accomplished astronomer like himself could tell the difference between an illusion and reality. But Maunder countered that the reason no one had seen canals before the late 19th century was that telescopes weren't good enough—we had been in the back of the room. Better telescopes brought us to the middle of the room, where we could see details but not clearly. When we got even better observatories, we would move to the front and know what was really there.

The final blow came from another wealthy amateur astronomer, Eugene Michel Antoniadi, originally from Greece. Antoniadi had believed in the canals and drawn maps of them, but he began to wonder if his eyes were playing tricks. In 1909, during an exceptionally close approach of Mars, he gained access to the largest telescope in Europe, outside Paris. One night, the air over Paris was dead still—perfect conditions. Mars sat in the telescope without wobbling, and Antoniadi, who knew exactly where the canals were supposed to be, saw nothing but natural features. He decided to take Lowell down.

Things unraveled quickly. Even Schiaparelli, shortly before his death in 1910, said the lines might be perfectly natural and that people should stop calling them canals. Camille Flammarion, the French astronomer who had inspired Lowell, backed away from the idea that the lines were anything more than natural features or illusions. Lowell was the last one holding the bag—and he dug in his heels. He argued that Antoniadi's telescope was too powerful, that its own power was creating illusions. He never gave an inch, claiming to his dying day that he was a suffering genius who would someday be proven right.

31:09Lowell's Legacy and Modern Parallels

Barron is careful not to dismiss Lowell entirely. He went into writing the book thinking it was a cautionary tale about one of the great blunders of science—a story about how we fool ourselves into believing things because we wish they were true. But he came to see it as also an inspiring tale. Lowell did a lot of good: his imagination pushed people to answer questions about Mars, and he inspired a generation of children to get excited about outer space.

Barron draws a distinction between two types of scientists: the conservative collectors who gather data objectively, and the dreamers who imagine how it all fits together into grand theories. Both are essential. The problem with Lowell was that he never knew when to back down. "There's a fine line between imagination in science and dreaming of what might be and getting excited about it, but knowing when to pull back when the evidence just doesn't support that."

The parallels to the present day are striking. Barron mentions an essay by Harvard legal scholar Cass Sunstein that compared Lowell to RFK Jr.—another person from a famous Massachusetts family who built a reputation around skepticism on vaccines, a position most of the scientific community considers bunk. Both are articulate, charismatic figures from privileged backgrounds who cast themselves as renegade outsiders fighting against orthodoxy. Barron notes that many people who promote skepticism are "not skeptical enough of themselves." He adds, "We all have to have the humility to understand that we are fallible human beings who, when we latch onto an idea, are loathe to give it up."

Conclusion

What stays with the listener is the uncomfortable recognition that intelligence and conviction are no defense against self-deception—and that the same psychological and social forces that drove the Martian craze are still operating today. The episode matters because it uses a seemingly quaint historical episode to illuminate something timeless about how we decide what to believe, especially when we desperately want it to be true. Lowell was wrong about Mars, but his story is not simply a cautionary tale about a kook; it's a nuanced exploration of the tension between imagination and evidence, between the dreamers who push science forward and the stubbornness that can keep it stuck.

Key takeaways

• Percival Lowell, a wealthy amateur astronomer from one of America's most prominent families, used his personal fortune and family connections to promote the theory that intelligent Martians had built a planet-wide network of irrigation canals.
• The "canals" were an optical illusion caused by looking at Mars at the limits of human perception through Earth's turbulent atmosphere—observers' eyes connected dots and saw straight lines where none existed.
• The Martian craze took hold in the Gilded Age because it offered hope during a time of violent labor unrest, political assassination, and vast inequality—the idea of a unified, morally superior Martian civilization was deeply appealing.
• Edward Walter Maunder's "Small Boy" experiment demonstrated that people at the right distance from an unclear image will draw straight lines, proving the canals were an artifact of perception, not reality.
• Eugene Antoniadi, another wealthy amateur who had believed in the canals, definitively disproved them in 1909 when perfect atmospheric conditions allowed him to see Mars clearly through Europe's largest telescope.
• Lowell never admitted he was wrong, claiming to his dying day that he was a misunderstood genius—illustrating how intelligence can be used to construct elaborate self-deceptions.
• The episode draws direct parallels to modern figures like RFK Jr., who use similar tactics of casting themselves as privileged insiders fighting against scientific orthodoxy while refusing to accept contrary evidence.