Extraterrestrial hypothesis
Overview
Hypothesis
A hypothesis is a proposed explanation for a phenomenon. The term derives from the Greek, ὑποτιθέναι – hypotithenai meaning "to put under" or "to suppose". For a hypothesis to be put forward as a scientific hypothesis, the scientific method requires that one can test it...
that some unidentified flying object
Unidentified flying object
A term originally coined by the military, an unidentified flying object is an unusual apparent anomaly in the sky that is not readily identifiable to the observer as any known object...
s (UFOs) are best explained as being extraterrestrial life
Extraterrestrial life
Extraterrestrial life is defined as life that does not originate from Earth...
or non-human aliens from other planets
Extrasolar planet
An extrasolar planet, or exoplanet, is a planet outside the Solar System. A total of such planets have been identified as of . It is now known that a substantial fraction of stars have planets, including perhaps half of all Sun-like stars...
occupying physical spacecraft
Spacecraft
A spacecraft or spaceship is a craft or machine designed for spaceflight. Spacecraft are used for a variety of purposes, including communications, earth observation, meteorology, navigation, planetary exploration and transportation of humans and cargo....
visiting Earth
Earth
Earth is the third planet from the Sun, and the densest and fifth-largest of the eight planets in the Solar System. It is also the largest of the Solar System's four terrestrial planets...
.
Origins of the term extraterrestrial hypothesis are unknown, but use in printed material on UFOs seems to date to at least the latter half of the 1960s. French Ufologist Jacques Vallee
Jacques Vallée
Jacques Fabrice Vallée is a venture capitalist, computer scientist, author, ufologist and former astronomer currently residing in San Francisco, California....
used it in his 1966 book Challenge to science: the UFO enigma.
