What is a UFO?

UFO refers to unidentified flying objects (bodies), that is, unidentified flying objects (bodies), which are floating and flying in the sky with unknown origin and nature.

UFO phenomena can be roughly divided into four categories: misunderstanding of known natural phenomena, unknown natural phenomena and unknown natural creatures. The fourth category refers to high-performance aircraft with obvious intelligent flight capability that are not disclosed by the Air Force, that is, some experimental disc aircraft that are not disclosed by the Air Force. It can be seen that UFOs and alien UFOs cannot be equated.

Flying saucer: refers to spacecraft from other planets, and the scope of UFO is much wider. Since the 1940s, a glowing flying saucer has been found over the United States. At that time, the newspaper called it "oval illuminant", which was the beginning of contemporary people's interest in UFOs. Later, people focused on UFO reports around the world, but so far no evidence widely accepted by the scientific community has been found to prove that they came from extraterrestrial civilization. The word UFO originated from the "Blue Book Project" of the US Air Force. The first person in charge of this project was Captain Edward Rupeldt, who officially invented the word "UFO" to replace the inaccurate and suggestive word "UFO" used at that time.