How Fascination With Aliens Spread Across 17th Century Europe
The debate over the existence of extraterrestrial life touches literature, religion, and science in 17th century Europe.
The following is an excerpt from First Contact: The Story of Our Obsession with Aliens, by Becky Ferreira.
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First Contact: The Story of Our Obsession with Aliens
The Alien Content Boom
There have been hints since antiquity that people will go absolutely bonkers for stories about extraterrestrials (see Lucian’s True History on page 10 and The Tale of the Bamboo Cutter on page 14). But nothing could prepare planet Earth for the explosion of interest in alien life that emerged in the Galilean age and, much like the ever-expanding universe itself, that obsession has only grown ever since.
In the decades following Bruno’s death, infatuation with aliens continued to spread across Europe like a slow-rolling ground fire, producing stories about weird inhabitants of the Moon and other planets. Then, in 1686, a young man named Bernard Le Bovier de Fontenelle threw a bunch of gasoline on these flames with the publication of the first alien blockbuster.
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With curiosity and charm to spare, Fontenelle had become a darling of the French intelligentsia by the time he published his masterpiece, Conversations on the Plurality of Worlds, at the tender age of twenty-nine. The book was inspired by his conviction that “nothing could be of greater interest to us than to know how this world we inhabit was made, if there are other worlds which are similar to it, and like it are inhabited too,” as he wrote in the preface.
To add a little spice to this topic, Fontenelle framed the book as a conversation between an inquisitive Marquise and a flirtatious male narrator who entrances her with cutting-edge astronomical research—ooh la la—as they stargaze over the course of five nights. (Then, as now, the best way to a woman’s heart is through a lengthy review of contemporary theoretical cosmology.)
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During the first few nights, the pair speculate about the nature of life on the Moon and in the solar system, resulting in memorable observations such as “Mercury is the lunatic asylum of the universe” and “Mars isn’t worth the trouble of stopping there.” On the fifth evening, the narrator and Marquise look beyond our solar neighborhood to the stars, which they conclude also host inhabited planets.
“Nature has held back nothing to produce [the universe]; she’s made a profusion of riches altogether worthy of her,” the narrator says. “Nothing is so beautiful to visualize as this prodigious number of vortices, each with a Sun at its center making planets rotate around it.”
Fontenelle not only widens the aperture of possible life to include the observable universe; he also anticipates the difficulty of detecting planets in other star systems, given that the immense glare of their host stars would drown out their own reflected light. This was just one of many important insights that Fontenelle popularized in his book, which also ruminates on Earth’s appearance to alien life-forms and the question of whether aliens might look similar to or radically different from humans.
The persecution of Copernican pioneers, like Bruno and Galileo, hung heavy over the seventeenth century, and Fontenelle clearly feared he might also run afoul of religious authorities. To that end, he tried to get ahead of any blowback by directly addressing his clerical critics.
“When I say to you that the Moon is inhabited, you picture to yourself men made like us, and then if you’re a bit of a theologian, you’re instantly full of qualms,” Fontenelle writes in the preface. “The descendants of Adam have not spread to the Moon, nor sent colonies there.”
By emphasizing his view that aliens are not descended from Adam, Fontenelle hoped he might have found what he called a “loophole” that allowed open discussion of the topic without inviting disproportionate condemnation.
The gambit seemed to have worked. Conversations was a major success that reinvigorated support for cosmic pluralism across the Western world, and it did not provoke much objection from religious authorities. The Copernican cat was, at last, out of the bag. Fontenelle also encouraged his readers to envision worlds beyond Earth as physical entities with unexplored landscapes, valuable resources, and exotic lifeforms. Not bad for a stargazing cad.
Aliens in the Scientific Revolution
As the seventeenth century wore on, scientists started to connect the dots between different subjects, as scientists are wont to do. Astronomical observations improved, revealing the cratered surfaces of the Moon and other planets—an anathema to Platonic predictions of perfect, featureless worlds.
Meanwhile, the dawn of microscopy exposed the existence of tiny living creatures, invisible to the naked eye, thriving all around us. These revelations suggested that there were countless niches where life could evolve beyond Earth, as well as an infinity of forms it might take.
For scientists like Christiaan Huygens, a Dutch polymath born in 1629, all of this evidence amounted to the obvious existence of aliens, which he called “Planetarians” in his influential 1698 treatise Cosmotheoros. “Now should we allow the Planets nothing but vast Deserts,” Huygens argued, “lifeless and inanimate Stocks and Stones, and deprive them of all those Creatures that more plainly speak their Divine Architect, we should sink them below the Earth in Beauty and Dignity; a thing that no Reason will permit.”
Put another way, it’s silly to conclude that all of these other planets, both in our solar system and beyond it, were inhospitable to life. What would be the point of them, then? As the seventeenth century gave way to the eighteenth, many other thinkers developed their own twists on this view, including Benjamin Franklin, Edmond Halley, William Herschel, Gottfried Leibniz, Immanuel Kant, and Thomas Paine.
As support for extraterrestrials flourished, people began to wonder how humans might stack up against these otherworldly species. I suspect Huygens would have been a Trekkie, as he dreamed of establishing interplanetary partnerships with other species in order to pool knowledge.
Others had a more self-effacing view of alien communications. David Rittenhouse, an American astronomer born in 1732, took a look around the world of his time and wondered why any intelligent species would want to establish communications with Earthlings—a common refrain to this day.
“We will hope that their statesmen are patriots, and that their kings (if that order of beings has found admittance there) have the feelings of humanity,” Rittenhouse said, according to the essays of Founding Father Benjamin Rush. “Happy people!—and perhaps more happy still, that all communication with us is denied. We have neither corrupted you with our vices, nor injured you by violence. None of your sons and daughters have been degraded from their native dignity, and doomed to endless slavery in America, merely because their bodies may be disposed to reflect, or absorb the rays of light, different from ours.”
As we see from this rather gloomy passage, opinions about aliens were beginning to more obviously reflect biases about life here on Earth. If you had a grim view of humanity, you might be a Rittenhouse-style pessimist about the prospect of alien contact. But if you yearned for a kinship between intelligent beings from all types of worlds, you might be more persuaded by Huygens-style alien optimism. The choice is yours!
Excerpted from First Contact by Becky Ferreira (Workman Publishing). Copyright © 2025. Design by Raphael Geroni.
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About Becky Ferreira
Becky Ferreira is a science writer whose work has appeared in The New York Times, Motherboard/VICE, WIRED, Popular Science, and other publications.