Ancient Astronaut Theory

In Intelligent Life in the Universe (1966) astrophysicists Iosif Shklovsky [Shklovskii] and Carl Sagan devote a chapter to the argument that scientists and historians should seriously consider the possibility that extraterrestrial contact occurred during recorded history; however, Shklovskii and Sagan stressed that these ideas were speculative and unproven. Shklovskii and Sagan argued that sub-lightspeed interstellar travel by extraterrestrial life was a certainty when considering technologies that were established or feasible in the late 1960s; that repeated instances of extraterrestrial visitation to Earth were plausible; and that pre-scientific narratives can offer a potentially reliable means of describing contact with aliens.