Crop circle

A crop circle or crop formation is a pattern created by flattening a crop, usually a cereal. Crop circles, as Taner Edis, professor of physics at Truman State University puts it, "all fall within the range of the sort of thing done in hoaxes." Although obscure natural causes or alien origins of crop circles are suggested by fringe theorists, there is no scientific evidence for such explanations, and human causes are consistent for all crop circles. A commentary in The Guardian noted that "[i]t is still open to dispute whether some are caused by natural phenomena or all created by human hand."

The number of crop circles has substantially increased from the 1970s to current times. There has been little scientific study of them. Circles in the United Kingdom are not spread randomly across the landscape but appear near roads, areas of medium to dense population and cultural heritage monuments, such as Stonehenge or Avebury. In 1991, two hoaxers, Bower and Chorley, made disputed claims to have created many circles throughout England after one of their circles was described by a circle investigator as impossible to be made by human hand.

Unidentified flying object

An unidentified flying object, or UFO, in its most general definition, is any apparent anomaly in the sky that is not identifiable as a known object or phenomenon. Culturally, UFOs are associated with claims of visitation by extraterrestrial life or government-related conspiracy theories, and have become popular subjects in fiction. While UFOs are often later identified, sometimes identification may not be possible owing to the usually low quality of evidence related to UFO sightings (generally anecdotal evidence and eyewitness accounts).

Stories of fantastical celestial apparitions have been told since antiquity, but the term "UFO" (or "UFOB") was officially created in 1953 by the United States Air Force (USAF) to serve as a catch-all for all such reports. In its initial definition, the USAF stated that a "UFOB" was "any airborne object which by performance, aerodynamic characteristics, or unusual features, does not conform to any presently known aircraft or missile type, or which cannot be positively identified as a familiar object." Accordingly, the term was initially restricted to that fraction of cases which remained unidentified after investigation, as the USAF was interested in potential national security reasons and/or "technical aspects" (see Air Force Regulation 200-2).

Circle

A circle is a simple shape in Euclidean geometry. It is the set of all points in a plane that are at a given distance from a given point, the centre; equivalently it is the curve traced out by a point that moves so that its distance from a given point is constant. The distance between any of the points and the centre is called the radius.

A circle is a simple closed curve which divides the plane into two regions: an interior and an exterior. In everyday use, the term "circle" may be used interchangeably to refer to either the boundary of the figure, or to the whole figure including its interior; in strict technical usage, the circle is only the boundary and the whole figure is called a disk.

A circle may also be defined as a special ellipse in which the two foci are coincident and the eccentricity is 0, or the two-dimensional shape enclosing the most area per unit perimeter squared, using calculus of variations.

Terminology

World

World is a common name for the whole of human civilization, specifically human experience, history, or the human condition in general, worldwide, i.e. anywhere on Earth or pertaining to anywhere on Earth.

In a philosophical context it may refer to:

In a theological context, world usually refers to the material or the profane sphere, as opposed to the celestial, spiritual, transcendent or sacred. The "end of the world" refers to scenarios of the final end of human history, often in religious contexts.

World history is commonly understood as spanning the major geopolitical developments of about five millennia, from the first civilizations to the present.

World population is the sum of all human populations at any time; similarly, world economy is the sum of the economies of all societies (all countries), especially in the context of globalization. Terms like world championship, gross world product, world flags etc. also imply the sum or combination of all current-day sovereign states.

UFO conspiracy theory

UFO conspiracy theories argue that evidence of unidentified flying objects and extraterrestrial visitors is being suppressed by various governments around the world, most notably the United States government. Such conspiracy theories commonly argue that Earth governments, especially the Government of the United States, are in communication and/or cooperation with extraterrestrials despite public claims to the contrary, and further that some of these theories claim that the governments are explicitly allowing alien abduction.

Various UFO conspiracy ideas have flourished on the internet and were frequently featured on Art Bell's program, Coast to Coast AM. According to MUFON, the National Enquirer reported that a survey found 76% of participants felt the government was not revealing all it knew about UFOs, 54% thought UFOs definitely or probably existed, and 32% thought UFOs came from outer space.

Notable persons to have publicly stated that UFO evidence is being suppressed include Senator Barry Goldwater, Admiral Lord Hill-Norton (former NATO head and chief of the British Defence Staff), Brigadier General Arthur Exon (former commanding officer of Wright-Patterson AFB), Vice Admiral Roscoe H. Hillenkoetter (first CIA director), astronauts Gordon Cooper and Edgar Mitchell, and former Canadian Defence Minister Paul Hellyer. Beyond their testimonies and reports no substantiating evidence has been presented to support their statements and conclusions. According to the Committee for Skeptical Inquiry little or no evidence exists to support them despite significant research on the subject by non-governmental scientific agencies.