Tarea

* A crop circle is a sizable pattern created by the flattening of a crop such as wheat, barley, rye, maize, or rapeseed. Crop circles are also referred to as crop formations, because they are notalways circular in shape. While the exact date crop circles began to appear is unknown, the documented cases have substantially increased from the 1970s to current times. Twenty-six countries reportedapproximately ten thousand crop circles in the last third of the 20th century. Ninety percent of those were located in southern England. Many of the formations appearing in that area are positioned nearancient monuments, such as Stonehenge. According to one study, nearly half of all circles found in the UK in 2003 were located within a 15 km (9.3 miles) radius of Avebury.
* Man-made
* Themost widely known method for a person or group to construct a crop formation is to tie one end of a rope to an anchor point, and the other end to a board which is used to crush the plants. Some cropformations are paid for by companies who use them as advertising. As an explanation of some of the more complex formations, physicists have suggested the use of GPS, lasers, and portable microwavegenerators.
* Weather
* Some have suggested crop circles are the result of extraordinary meteorological phenomena ranging from freak tornadoes to ball lightning. The first known published referenceto the possibility of crop formations being the result of natural phenomena dates back to 1880 in which investigator and amateur scientist John Rand Capron theorized the formations may have been theproduct of "cyclonic wind action..." Physicist Stephen Hawking expressed the opinion in 1992 that, "Corn circles are either hoaxes or formed by vortex movement of air"
* Paranomal
* Sinceappearing in the media in the 1970s, crop circles have become the subject of speculation by various paranormal, ufological, and anomalistic investigators ranging from proposals that they were created...