UFO

A UFO, or unidentified flying object, is widely considered to be a stereotypical alien ship seen in the sky for brief moments before vanishing. Originally called "Foo Fighters" or "Ghost Rockets" when spotted above battlefields in World War II, these ships are theorized to be anything from spacecrafts of people from far away, secret military planes, and even geological events. The term, UFO, first became popular in the 50's. It is also believed widely that the governments would cover up the existences of these objects to due conspiracy theories such as allegiances with the aliens or being top secret planes decades ahead of current technology. There are also many cases of objects similar in description to UFO's found in the past texts and many different religious and scientific documents.