free download PNG images :Ufo

Unidentified flying objects (UFOs) are not easy to recognize objects observed in the sky. Most UFOs were later identified as conventional objects or phenomena. The term is widely used for observations of spacecraft in outer space that require protection.

The term "UFO" (or "ufob") was coined by the United States Air Force (USAF) in 1953 and is a collective term for all such reports. In its initial definition, the U.S. Air Force stated that "ufob" is the object of "any aircraft or missile type that does not conform to any currently known aircraft or missile type in terms of performance, aerodynamics or abnormal characteristics, or can not be identified with certainty as a familiar airborne object" As a result, the term was initially limited to those parts of the case that have not been identified since the investigation, as the US air force is interested in potential national security reasons and / or "technical aspects" (see air force regulations 200-2).

In the late 1940s and throughout the 1950s, UFOs were commonly referred to as "flying saucers" or "Frisbees.". The term UFO began to become more widely used in the 1950s, initially in technical literature, and later widely used. During the cold war, UFOs aroused great interest. In this era, people pay more and more attention to national security. Recently, in the 2010's, the reason is unknown. However, various studies have concluded that this phenomenon does not constitute a threat to national security, nor does it contain anything worthy of scientific pursuit (such as the flying saucer working group in 1951, the CIA Robertson group in 1953, the US Air Force blueprint program, and the Condon Committee).

The Oxford English Dictionary defines a UFO as "a UFO; a UFO.". Donald E. keyhoe wrote the first book to use the word.

The acronym "UFO" was created by Captain Edward J. Rupert, the blue book program leader, when the U.S. Air Force formally investigated the UFO. "It is clear that the term 'flying saucer' is misleading when applied to objects of all possible shapes and properties," he wrote. As a result, the military prefers a more generic name (if lighter): UFO. UFO (pronounced Yoo foe). " Other phrases formally used before the UFO acronym include "flying flackjack", "flying disc", "unexplained discs" and "unidentifiable object".

After the summer of 1947, the term "flying saucer" has been widely concerned. On June 24, a civil aviation pilot named Kenneth Arnold reported seeing nine objects flying in formation near Mount Rainier. Arnold aimed on time and estimated the disc speed to be over 1200 mph (1931 kph). At that time, he claimed that he described flying objects in the shape of flying saucers, which led to the appearance of "flying saucers" and "flying saucers" in the newspapers.

In general use, the term "UFO" is used to refer to the claim of an alien spacecraft, and some economists and researchers prefer to use terms such as "UFO" (UAP) because of public and media ridicule related to the subject. Or "anomalies," such as the title of the National Aeronautical Reporting Center (narcap). Sometimes in military aviation environment, "abnormal aircraft" (AAV) or "unidentified aviation system" (UAS) are also used to describe unidentified targets.

After years of investigation, the scope and scientific preciseness of UFOs are different. As we all know, the government or independent scholars of the United States, Canada, Britain, Japan, Peru, France, Belgium, Sweden, Brazil, Chile, Uruguay, Mexico, Spain and the Soviet Union have investigated UFO reports many times.

Among the most famous government studies, the ghost rocket investigation conducted by the Swedish military (1946-1947), the blue book project (formerly project logo and project hatred), which was conducted by the US air force from 1947 to 1969, the secret US Army / air force "flash and flash" project to investigate the green fireball (1948-1951), and the US Air Force secret plan blue of the batel Memorial Institute Pishu special report No. 14, and the 1977 opera "operation saucer" of the Brazilian air force. Since 1977, France has carried out an ongoing survey (gepan / sepra / geipan) at its National Centre for Space Research (CNEs); since 1989, the government of Uruguay has carried out a similar survey.

On this page, you can download free pictures: UFO pictures download free