The full name of UFO is UFO, also known as UFO. The English word is UFO, which refers to an object with unknown origin, space, structure and nature, but floating and flying in the air. UFO was recorded in Ezekiel in ancient Europe, and in ancient China, UFO was also called Star Scout.
Since the 1940 s, luminous elliptical disc aircraft have been found over the United States. At that time, the newspaper called it "oval luminous body", which was the beginning of contemporary people's interest in UFOs. Later, people focused on UFO reports all over the world.
Classification of UFOs
1, for known flying objects or known natural phenomena, known life forms, such as balloons, airships, satellite rocket wreckage, insects, birds, etc.
2. The illusion and psychological phenomenon of some social groups or individuals in a specific environment.
3. Unknown natural life. Biologists believe that there should be a fourth kind of life in nature besides solids, liquids and gases, but this has not been confirmed.
4, unknown natural phenomena, such as the earth's light fireball, ball lightning, plasma.
5, people can't make, can't fully understand the intelligent aircraft or flying objects, that is, people often say "flying saucer" and "alien".