Crop circles, those mysterious patterns farmers find in their fields, are the stuff legends are made of.
Some have said these elaborate etchings have been left behind by UFOs; others are quick to call them the work of highly artistic hoaxers.
Then there are those who believe crop circles are formed by unusual weather patterns, military experiments the government doesn't want to talk about -- or even stoned Australian wallabies.
Crop circles have cropped up in popular media, appearing in episodes of The X-Files, Dark Skies and in director M. Night Shyamalan's 2002 movie Signs.
Now University of Oregon physicist Richard Taylor has suggested that crop circle artists using GPS devices, lasers and microwaves are responsible for the astonishing patterns of geometric forms found in the fields.
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"Crop circle artists are not going to give up their secrets easily," Taylor wrote in the August 2011 issue of Physics World. "This summer, unknown artists will venture into the countryside close to your homes and carry out their craft, safe in the knowledge that they are continuing the legacy of the most science-oriented art movement in history."
These intricate dynamic works of art result when someone or something causes crops, like wheat, barley, corn and rye, to flatten in ways that produce amazing images, mostly discernable from the air. In many cases, they're referred to as crop formations, because they're much more than circular.
But it's not just a current phenomenon. Crop circle reports go back to the late 1800s. Part of the crop circle mythology holds that a farmer or rancher will go to sleep having noticed nothing unusual in any of his fields until the next morning where he discovers that, overnight, a stunning, often complex pattern has formed in the middle of a field.
And surprisingly, some people have claimed to see crop circles appear when no other humans were in the fields creating them.
"There have actually been about 50 documented eyewitnesses to crop circles forming, so people have seen them during the daytime -- they don't all appear at night," said Jeffrey Wilson, director of the Independent Crop Circle Researchers' Association, a small group that investigates crop circles. "In these circumstances, there had been no unusual lights or sounds, but every one of the cases had happened during the passage of a storm front or a severe weather front.
"That's generally not talked about in media, and skeptics don't buy into any of that -- they just dismiss all the eyewitness cases," Wilson told The Huffington Post.
Wilson isn't the only one who has taken issue with the common assumption that crop formations are elaborate man-made hoaxes. In fact, there is a whole group of observers that have proposed alternative theories of how the designs are made. In many cases, they aren't just challenging conventional wisdom -- they are challenging each other.
"The first time I ever walked into a crop formation in Milk Hill [England] was the summer of 1992. The wheat pattern was 360 feet long and had some kind of a residual electrostatic field still around it -- it felt like walking into jello along the edges," said Linda Moulton Howe, author of Mysterious Lights and Crop Circles and one of the key speakers at the recent Mutual UFO Network symposium in Irvine, Calif.
Howe, a multiple Emmy Award-winning producer, investigative reporter for Premiere Radio Networks and editor of the Earthfiles website, has studied worldwide crop circles since 1991 and has been inside 250 of the formations.
"When you encounter something that is not like your normal everyday walking along the street, it gets your attention and it makes you look at what's in front of you in a different way," Howe told The Huffington Post.
Her research focuses on evidence that contradicts Taylor's theory that artists are using GPS, microwaves and lasers to create crop circles.
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"In 1999, there were simultaneous formations in Avebury, England and Whitefish, Mont., completely separated by oceans and continents, but they had the same biophysical change in the stems underneath the seed heads that became looped and twisted," Howe reported.
Biophysicist W. C. Levengood examined the plant cellular abnormalities and concluded, "Spinning plasma energies hit these plants probably right after flowering, but the formations were not visible until a few weeks later. That means something knows how to interact spinning plasmas with plants at different times from seed to adult growth to create the eventual patterns I have studied."
Plasma is a gaseous state of matter with positively charged ions and negatively charged electrons. Glowing polar auroras are common Earth plasmas.
Levingood has analyzed thousands of crop formation plants and written a number of important scientific papers, including one for the 1994 edition of plant biology journal, Physiologia Plantarum, in which he proposed his "spinning plasma energy" idea.
"Crop formations consist of geometrically organized regions in which the plants (primarily grain crops) are flattened in a horizontal position," Levengood wrote in that article. "Plants from crop formations display anatomical alterations which cannot be accounted for by assuming the formations are hoaxes.
"The affected plants have components which suggest the involvement of rapid air movement, ionization, electric fields and transient high temperatures combined with an oxidizing atmosphere. One naturally occurring and organized force incorporating each of these features is an ion plasma vortex."
That's a slightly more elaborate explanation compared to a few guys walking around fields using wooden planks and ropes to create crop circles.
"It's time that people realize there are changes that have happened in these crops that cannot be explained in any other way except through advanced interactions with energies," Howe noted.
While most reports of crop circles emanate from England, the truth is that these odd ground formations show up in many countries.
"In the United States, we have records of over 600 reports, approximately 200 in Canada and many others in Germany, the Netherlands, across Europe and in Australia," said Wilson, who has worked in radio astronomy and physics and mapped the elements of the surface of the moon for NASA.
Wilson also acknowledges "a serious hoaxing problem" in England.
"The vast majority of the ones reported in England are definitely man-made. Any serious researcher who has gone over there and looked at them will tell you that -- I looked at seven formations carefully in 2006, and all of them were man-made."
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Like Howe, Wilson disagrees with Taylor's idea about microwaves and lasers.
"It's ludicrous. All of his explanations, whether it's radiations from a magnetron pulled out of a microwave oven or lasers from the sky -- those things don't hold water. Mostly because we have evidence and photographs of crop circles from a time earlier than the history of microwaves and lasers."
Howe has produced acclaimed documentaries on science, medicine, the environment and Earth mysteries. And she's worked with many scientists, like Levengood, who have quietly examined crop circle evidence that was hard to explain.
"He was the first to establish that what was happening in the growth nodes of the crop circle plants could only occur if there was an exposure to high heat for only seconds, because if it goes any longer, the plants will scorch and we have never found black carbon on the surfaces of any of the crop formations that I've been in and studied," she said.
Wilson is undecided about what he thinks crop circles -- the non man-made ones -- will turn out to be.
"I actually think there may be more than one source cause that makes crop circles. I think there are multiple sources and a range of possibilities that are still available.
"There are natural processes that make complex geometry, so it's not unprecedented in nature. I'm not 100 percent convinced it's from an intelligent source -- it's unproven at this point."
But Howe has seen mysterious moving small lights over crops and formations in England and has worked with Italian astrophysicist Massimo Teodorani, studying mysterious plasmas in the mountains of Hessdalen, Norway.
"He said there appears to be intelligence in these plasmas, as if programmed. But what is doing the programming?"