Last night the sky appeared a movement of an unknown object, Alice considered a UFO, because it is flying very fast. Jack that is light wind. The full name of UFO UFO, also known as UFO (unidentified flying object, referred to as UFO) is unknown, unknown space, unknown structure, the nature is unknown, but floating, flying objects in the air. Some people believe it is the spacecraft from other planets, some people think that UFO is a natural phenomenon. 1940s, the United States found that over the dish to an aircraft, then called the "flying saucer, which is the contemporary interest in the beginning of the UFO, then people look at UFO reports from around the world, but has not yet been found can indeed evidence of the letter many UFO photos by experts as a hoax, and some were considered to be
ball lightning, but there is always some that can not be explained based on existing scientific knowledge.本回答被提问者采纳