Ufo. Before the word "UFO" appeared, only the word "UFO" was used to refer to such objects in English, but it often caused misunderstanding. Since the 1940s, saucer-shaped flying objects have been found over the United States, which were then called "flying saucers" and regarded as new reconnaissance weapons of the Soviet Union. This is the beginning of contemporary people's interest in UFOs, and later people focused on UFO reports around the world.

On June 24th, 1947, Kenneth Arnold, an American, suddenly found nine white saucer-shaped UFOs while flying over Mount Rainier in Washington. According to his visual observation, these objects flew at a high speed of about 1600 or 1900 kilometers per hour and disappeared in the blink of an eye. He shouted to the ground tower, "I saw a flying saucer." I saw a flying saucer. ) caused a great sensation in America. Because the word UFO is well described, it is widely circulated all over the world. Later, a reporter used the abbreviation UFO for the first time in a newspaper, and people have been using it ever since.