On a January morning in 1966, a farmer named George Pedley was driving his tractor on his neighbor’s land near Horseshoe Lagoon, just outside the Queensland, Australia, town of Euramo, when he heard a hiss. Shortly afterward, he claimed, he saw a flying saucer rise from the nearby swamp, where he believed the strange sound had come from, and fly away.

Pedley left the tractor and went over to the swamp to investigate. There he found a swath of reeds swirled clockwise into a circle, by his estimate, 30 feet in diameter. Later, with the help of his neighbor, Albert Pennisi, Pedley waded into the water among the reeds and discovered that they had been fully uprooted. The effect was something like a giant (perhaps even flying saucer-sized) floating nest, the reeds, presumably, pressed flat in the direction of a spinning craft taking flight from among them.

The local press took interest, as did other farmers, and soon five more “nests” were found. There is, if you’d like to know how they were situated, a diagram. Despite the fact that a number of residents said the circular reed pattern was a fairly common swamp event during the beginning of the wet season—and a local police officer together with the University of Queensland concluded the effect was most likely caused by a “willy-willy,” which is apparently the delightful name given to dust devils by the Australian people—the “saucer nest” story took off. Called the “Tully nests” after another nearby town, the events of 1966 made an Australian Roswell of the sightings, inspiring dozens of residents and UFO enthusiasts to record circle patterns found among the reeds for years afterward.

All in all, the alien theory raised a lot of difficult questions.

The Tully nests, too, became the precursor to a much wider and well-known phenomenon, one that has inspired countless devotees, scientific (and not-so-scientific) debate, and one fair-to-middling M. Night Shyamalan movie: crop circles.

CROP CIRCLES AS WE know them today—circular patterns, often intricate, formed from wheat, barley, and other crops pressed flat or bent in half, so that, from above, the field looks stamped—started showing up in the English countryside in the late 1970s. As is the case with many other mysterious phenomena, their prevalence and their press coverage worked together in a feedback loop. The circles got bigger, and more detailed, and they showed up near Stonehenge and gravesites. People started writing books about them. Enthusiasts of the phenomenon called themselves “cereologists," not, confusingly, after the breakfast food, but in honor of the Roman goddess of vegetation, Ceres. Sometimes, adorably, they also called themselves “croppies.”

Croppies believed that the circles were put there by extraterrestrials that wanted to send us a message. In one of the more straightforward examples, the sentence “WE ARE NOT ALONE” appeared in an English field of crops in 1987. Skeptics argued that if the message really came from aliens, and they spoke English, the logical thing would have been to write “YOU” rather than “WE.” True, but it’s also a very specific issue to take with the grander question of whether extraterrestrial species a) exist, b) are communicating with us, and c) if they are, whether folding cornstalks into the shape of words was the most practical way to do so. All in all, the alien theory raised a lot of difficult questions.

Other cereologists theorized that crop circles were caused by “plasma vortices,” or “small, local whirlwinds of ionized air.” Plasma vortices—also called “ball lightning”—though, are an unexplained (and quite possibly specious) phenomenon, unable to convincingly explain yet another. Still, these theories held sway among crop circle researchers for much of the 1980s.

Then, in 1991, Doug Bower and David Chorley—two self-proclaimed “pranksters”—came forward to claim responsibility for most (if not all) of the crop circles across Southern England over the past 10-plus years. They had a tool: a wooden plank affixed to a rope, and a baseball cap holding a roll of wire to keep their lines straight while they walked around creating the circles. In a press event, Bower and Chorley created a crop circle like others they’d made in the past. A cereologist named Pat Delgado, who wasn’t informed of the circle’s origins, was invited to examine it. Perhaps not surprisingly, Delgado deemed the circle “authentic.” He was then informed that Bower and Chorley had made it themselves hours earlier. (Which is kind of a mean way to prove one’s point, isn’t it? I can’t stop thinking about this guy Pat carefully prodding the cornstalks, taking measurements in a little notepad, using whatever admittedly questionable criteria he used to determine crop circle authenticity, excitedly telling a crowd of cameras that this one was real before being told the whole thing was just a joke. I feel sad for him 22 years later.)

Bower and Chorley’s confession closed the case for most of the general public, and a good number of believers too. But for years afterward and through today, despite the fact that the phenomenon started with a probably-natural-and-normal ring of reeds in a swamp and a series of hoaxes, cereologists have attempted to make the scientific case for non-human-made crop circles. They just haven’t done a very good job.

A 2005 PAPER CALLED “Balls of Light: The Questionable Science of Crop Circles,” written by three researchers from the amazing-sounding organization Italian Committee for the Investigation of Claims of the Paranormal, lays out several of the predominant theories only to poke holes in them one by one. The first, published in a scientific journal by W.C. Levengood in 1994, argued that “anatomical alterations” such as the expansion of stem nodes in crops found inside the circle formations proved that some electromagnetic event had taken place to cause them. Another virtually unintelligible theory called the “BOL” hypothesis (for “ball of light”) involved a model designed to describe “the decrease with distance of the intensity of a spherical electromagnetic wave front centered at a point source located at a finite height, h, above the field.”

It won’t shock anyone to learn that the cereologists’ studies examined in this paper were found to be a mess. They feature missing data, questionable use of statistics, and a tenuous-at-best grasp of the biology of the plants in question. They feature, implicitly, a desire to make something more of crop circles than what is probably the sad, boring, unimaginative truth: people are just sneaking out into fields at night, bending cornstalks in half.

Maybe because they’re so precise and so pretty, it seems like there should be more to the story. In the research for this piece, though, just one glimmering spot of hope emerged: sometimes, back in Australia where this whole thing started, a wallaby will eat an opium poppy or two, and then it will run in circles over and over until the poppy crops beneath it are crushed. This is how you end up with a beautiful headline like “Stoned Wallabies Make Crop Circles.” And if aliens weren’t really ever involved (and I’m not saying for sure they weren’t), and neither were plasma vortices, this explanation seems a close second-best.