Scariest UFO Best Documentary 2017 Extraterrestrial life,[n 1] also called alien life (or, if it is a sentient or relatively complex individual, an "extraterrestrial" or "alien"), is life that does not originate from Earth. These hypothetical life forms may range from simple single-celled organisms to beings with civilizations far more advanced than humanity. Although many scientists expect extraterrestrial life to exist in some form, there is no evidence for its existence to date. The Drake equation speculates about the existence of intelligent life elsewhere in the universe. The science of extraterrestrial life in all its forms is known as exobiology. Read more : https://en.wikipedia.org/wiki/Extraterrestrial_life May you find this video informative and be thrilled to subscribe for more. Thanks for watching!