Alien

Aliens are supposed material beings from other planets.

In science and religion
The Church has not officially ruled on the existence of aliens. Neither the Bible nor the Apostolic Tradition mention anything about it. The existence of these beings would not change Catholic doctrine at all. The Bible teaches us that God has supremacy and absolute power over everything created.Science has also not detected any signs that suggest the existence of aliens. There is not the remotest indication that aliens exist.

In other words, opinions about its existence are not based on either science or religion. They are nothing more than mere opinions about something we do not know.

Fame in Popular Culture
In popular culture and in ufología, anything originating from somewhere in the Cosmos outside the Earth or its atmosphere is considered "extraterrestrial". Although the word "extraterrestrial" is used for everything that is alien to Earth, most people only take it into account when referring to beings from space. In general,  'intelligent extraterrestrial life'  is associated with UFOs. Regarding the definitions of "alien" and "extraterrestrial" it is necessary to denote that there is a difference between their definitions. Extraterrestrial, clearly, is a word created to explain in simple terms the origin of these beings. On the other hand, the word “alien” is of English origin and its most common meaning is “foreign”, “strange” or “alien” (here they coincide with the Latin etymology –alienare– of the Spanish verb “alienar”), although In English as in Spanish, the use of the word  alien  is popular to refer to extraterrestrial beings, although that was not the original and exclusive meaning of the word.