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9 UFO Sightings No One Can Explain

Updated: Aug. 22, 2023

Lots of unidentified flying objects turn out to be weather balloons, clouds, or planes, but there are definitely sightings that can't be explained away so easily.

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white weather balloon in the air above the trees

Most UFOs don’t stay unidentified

UFO sightings often turn out to have very simple explanations, such as “aircraft, astronomical objects, rocket launches, balloons (escaped party balloons at sunset are particularly effective!), birds, insects, intensely bright squid lights used by Japanese fishermen, and so forth,” says Seth Shostak, senior astronomer and fellow at the SETI Institute, which is dedicated to exploring the origins of life and intelligence in the universe. In 1973, before he became president, Jimmy Carter reported seeing a UFO, but it’s widely believed to have been the planet Venus. The debris found at Roswell Army Airfield in New Mexico in 1947 turns out to have been from a top-secret experimental spy balloon project that wasn’t declassified for almost half a century.

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Modern US Navy jet fighter taking off with lots of power
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But not all can be explained away

In December 2017, the U.S. Department of Defense acknowledged to The New York Times that it had been running a program focused on investigating unidentified flying objects, or UFOs. The Advanced Aerospace Threat Identification Program (AATIP) received about $22 million in funding between 2007 and when it was shut down in 2012, according to the Pentagon. Two infrared videos were released with the articles that showed an encounter between Navy fighter jets and a UFO off the coast of California in 2004. Commander David Fravor, who was piloting one of the jets, told the paper that after a radio operator asked him to check out a mysterious aircraft, he flew to the specified location and saw the seawater churning below him. A whitish, oval-shaped aircraft was hovering above the water. “It accelerated like nothing I’ve ever seen,” Fravor told the Times, admitting that it made him feel “pretty weirded out.” Unfortunately, definitive proof that aliens are real or not is just one of those science mysteries no one has figured out.

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Flying saucer UFO over bluff/ cliff side in summer, clear blue sky background, CGI recreation
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Unidentified, but not necessarily alien

Of course, just because there’s no explanation for an event does not mean it was a visit from extraterrestrial intelligence. There are plenty of phenomena that scientists don’t understand—they’re not even sure why ice is slippery. Shostak says he doesn’t know exactly what the AATIP videos show (though he has some ideas), but he’s not convinced that they indicate cosmic visitors: “There’s no explanation for about one-third of the murders in New York City,” he says. “Nonetheless, that doesn’t mean that they weren’t committed by people!”

Still, humans have been spotting mysterious objects in the sky for centuries, with cases increasing dramatically in the middle of the twentieth century when aviation and the Cold War presumably made people extra wary of unexplained lights in the sky. Here are a few of the most notable examples of encounters that haven’t been solved yet.

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China, 11th century

Around the year 1088, Shen Kuo, a well-respected poet and military tactician, wrote a book called Dream Pool Essays (named after his garden estate) that covered his scholarship in astronomy, mathematics, geology, zoology, botany and more. In the book, he describes what might be the first recorded UFO sighting; an object nicknamed “the Pearl” regularly appeared in the sky over Yangzhou province. Its door would open and very bright light would pour out. “The spectacle was like the rising sun, lighting up the distant sky and woods in red,” according to the text.

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View of Mount Rainier with a lake in the foreground
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Mount Rainier, Washington, 1947

The flying-saucer era can be traced back to a sighting of a UFO that didn’t even look like a saucer. Amateur pilot Kenneth Arnold was flying over Washington on a clear June night when he spotted a flash of bluish light near Mount Rainier. Then he saw more—nine flashes in total. He said the lights moved around, like “the tail of a Chinese kite,” according to a 1967 book about the incident by Ted Bloecher. Arnold at first thought they were jets, then maybe geese, and then he ruled both of those out and did not know what he was looking at. Later, when he described the sight to reporters, he said something about how the lights moved “like a saucer if you skip it across the water.”

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Rocks of Fire near canyon in New Mexico
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Socorro, New Mexico, 1964

By the mid-1960s, UFOs were being investigated by the U.S. government through Project Blue Book, and space alien plots were common in movies and TV shows; The Outer Limits series started in 1963. When Socorro, New Mexico, police officer Lonnie Zamora heard a loud roaring sound and saw a flame in the sky, he abandoned the speeding car he’d been chasing to check it out. He found a round object in a canyon and saw two figures in white near it, but as he got closer, the object flew away. Investigators from Project Blue Book apparently believed Zamora wasn’t making up the story and weren’t able to come up with a clear explanation (despite the event’s proximity to the White Sands Missile Range). They classified the case as “unidentified.” It didn’t help matters that this sighting was relatively close to the infamous Area 51. Find out all the secrets about Area 51 the US government won’t tell you.

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Scenic landscape with lake and sunset at evening in Koli, national park, Finland
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Finland, 1969

A group of fighter pilots on a navigation flight saw seven objects shaped like disks or balloons hovering about 5,000 feet in the air over a field. As the jets approached, the objects flew off at what the air force pilots called astonishing speed, according to an article in the Finnish Defense Forces’ magazine, Ruotuväki. The incident is the only UFO encounter acknowledged by the country’s air force.

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Production of lavender in Sault France Europe

France, 1981

When the French UFO investigation division (called GEIPAN) released its records to the public in 2007, its website crashed from too many users. One of its most famous unexplained cases happened near the southern village of Trans-en-Provence, where a resident said an 8-foot oval-shaped craft landed on his property and then quickly took off again. It left behind marks, which GEIPAN confirmed appeared to have been made by a heavy object.

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Aerial view of New Jersey Turnpike, New Jersey
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New Jersey Turnpike, 2001

Several drivers actually pulled off the highway to get a better look at what they described as a group of golden-orange lights moving quietly overhead near the Arthur Kill Waterway. One of the witnesses was a lieutenant from the nearby Carteret Police Department. Air traffic controllers couldn’t come up with any explanations, and the National Weather Service didn’t have any ideas either.

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Aerial view of Chicago's O'Hare airport
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Chicago O’Hare International Airport, 2006

On a cold November afternoon, pilots, ramp workers, mechanics, and United Airlines employees working at or near Concourse C at O’Hare saw what looked like a very unusual aircraft hovering above the airport. All described it as a shiny gray disc, according to the Chicago Tribune, and some thought it was spinning. After several minutes, it shot silently upward and punched a hole in the cloud above. Unfortunately, nobody got a photo or video, and the Federal Aviation Administration said it hadn’t caught anything on its radar systems. You’ll also want to check out the 13 weirdest things archaeologists have ever found.

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Four Peaks, a prominent landmark of the Mazatzal Mountains on the eastern skyline of Phoenix, Arizona, is framed by tall saguaro cacti in the desert.
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Arizona, 2018

Two commercial pilots—one in a Learjet and the other flying an American Airlines plane—both reported seeing an object pass two or three thousand feet over them in Arizona airspace in February. The Federal Aviation Administration released the radio exchanges between the pilots and the air traffic controller and confirmed that it did not know of any other aircraft that was supposed to be in the area at the time, according to Fortune.

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Space satellite orbiting the earth. Elements of this image furnished by NASA
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Civilian reports

The SETI Institute’s Seth Shostak says he’s received thousands of reports of sightings that witnesses can’t explain. “I hear from members of the public every day who have seen or experienced something they attribute to alien presence,” he says. But he’s not convinced that aliens are invading, and he doesn’t think we should worry. “Keep in mind that there are more than 3,000 satellites in orbit making images of the Earth—many at very high resolution. If we were really being buzzed by extraterrestrial craft, they would be seen by satellites all the time.” The truth about civilian claims (rather than scientific claims) are just one of the UFO myths scientists want you to stop believing.