20 Historical Figures Obsessed with the Search for Extraterrestrials

Before being banished from Athens for blasphemy, this presocratic philosopher was convinced that the Moon had hills and craters teeming with life. Even though this was not considered valid scientific reasoning in the 5th century B.C., this man deserves credit for standing up for his beliefs. His ideas helped advance early thinking about celestial bodies beyond mere observation.

Several centuries before Galileo first pointed his telescope at the sky, Bruno had hypothesized that the stars were suns surrounded by their own planets. Building on this, he engaged in an incredibly bold line of reasoning and concluded that they must all be inhabited, since God is infinite and would not create life just once. His ideas were controversial, but undeniably ahead of their time.

Kepler is best known for discovering orbital mechanics, but that didn’t stop him from writing a fanciful tale about a journey to the Moon. In it, he depicted aliens who had evolved to gigantic sizes in order to stay warm at night. Kepler provided numerous sound scientific explanations to justify why the lunar aliens would not resemble humans.

The scientist credited with discovering Saturn’s largest moon spent his final years reflecting on and writing about extraterrestrial life. He believed that God would not have wasted water and vegetation on Earth without also placing them elsewhere in the universe. With his deeply logical mind, Huygens undoubtedly imagined that extraterrestrials had fingers and toes, just like humans.

Sir William Herschel is best known for discovering Uranus, but he held some rather outlandish beliefs about extraterrestrial life. He suspected that the Sun was actually a solid mass capable of supporting plant and animal life. Furthermore, he claimed to be able to make out forests and circular structures on the Moon.

One of the Founding Fathers of the United States clearly wrote that he believed the universe was teeming with life. He felt it was unfair to think that God would have placed so many shining stars in the sky without anyone nearby to observe them and admire His creation. Just imagine what Ben Franklin would think of today’s UFO sightings.

In his political pamphlet titled Common Sense, Thomas Paine challenged the idea that there is only one world inhabited by living beings. He argued that believing this would contradict all scientific discoveries about the solar system. He certainly deserves some fireworks, because he wanted to liberate far more than just one planet.

Lowell was a wealthy astronomer obsessed with the idea that aliens were building canals on Mars. He had a private observatory built so he could map these artificial waterways that he believed he could clearly make out. Even if the aliens weren’t real, they certainly existed in the minds of the millions of people who read his books and attended his lectures.

Not content with revolutionizing the world through his electric innovations, Tesla also tried his hand at receiving radio signals from Mars. At one point, he announced to the press that he had picked up a series of signals that clearly originated from highly intelligent beings. He spent decades building devices that, in his view, could facilitate interplanetary contact.

Unbeknownst to most people, the inventor of the radio, Guglielmo Marconi, attempted to contact Mars using his own scientific equipment. He mentioned during a lecture that he frequently picked up high-frequency whistling sounds that did not originate from Earth or its atmosphere. Marconi stated that it would be reasonable to assume that they originated from a highly advanced civilization.

The French astronomer Flammarion was not only a best-selling author of his time, but he was also convinced of the existence of extraterrestrials on other planets. Not content to limit himself to his knowledge of physics, he hypothesized that human spirits would inhabit other planets after their death on Earth. His ideas blended science and mysticism in an unusual way.

The Russian rocket scientist Tsiolkovsky once said that his life’s work was merely a stepping stone toward encountering extraterrestrial civilizations. He believed that our planet was very young and primitive compared to what he imagined existed elsewhere. His vision helped inspire future generations of space explorers.

Using a massive telescope nicknamed the “Leviathan of Parsonstown,” this Irish aristocrat peered deeper into space than anyone before him. He was convinced that the strange spiral shapes he observed in the sky were actually star clusters harboring life. His detailed drawings of these galaxies helped people realize just how many worlds might be home to extraterrestrials.

This French writer became famous for a book in which a philosopher explained the inhabited universe to a charming noblewoman. In it, he argued that it was pure and simple arrogance to believe that humans were the only creatures endowed with reason in such a vast expanse. His lighthearted approach made the question of extraterrestrials a very popular topic in Parisian salons.

The German philosopher Immanuel Kant publicly ranked the intelligence levels of potential extraterrestrial species. He hypothesized that the closer a planet was to the Sun, the lower its general intelligence would be. While this logic may seem strange today, Kant was fully convinced of its validity.

Burton was the somewhat melancholic author of The Anatomy of Melancholy. He was fascinated by the idea of infinite worlds, at a time when science was just beginning to flourish in the 17th century. He wondered whether other worlds might have their own priests and kings, ready to wage war over lands and gods.

As a renowned physicist and the inventor of the kaleidoscope, Brewster maintained that God would not have created empty planets. He believed that every celestial body was home to intelligent beings capable of appreciating the splendor of the universe. He even opposed scientists who claimed that Earth was unique or special.

American journalist Richard Locke published a series of articles describing life on the Moon. In what became known as the “Great Lunar Hoax,” he claimed that astronomer John Herschel had discovered reptilian humanoids. Although this information was false, readers around the world desperately hoped that these aliens actually existed.

If the saying “it takes one to recognize one” is to be believed, then Wernher von Braun, a leading rocket scientist at NASA, was obsessed with little green men. He wrote countless articles describing how to organize a mission to Mars to find evidence of a lost civilization. After helping to send a man to the Moon, von Braun continued to work toward the exploration of other worlds.

Although he lived in the modern era, Sagan’s legacy is rooted in a deep, age-old passion for making contact. He asserted that “extraordinary claims require extraordinary evidence,” yet he remained one of the most ardent advocates for the exploration of space. By including music and welcome messages aboard the Voyager probes, he ensured that humanity’s message would travel through the stars for generations to come.