"Ancient astronauts" (or "ancient aliens") refers to a pseudoscientific hypothesis, that intelligent extraterrestrial beings visited Earth and made contact with humans in antiquity and prehistoric times. Proponents suggest that this contact influenced the development of modern cultures, technologies, religions, and human biology. A common position is that deities from most, if not all, religions are extraterrestrial in origin, and that advanced technologies brought to Earth by ancient astronauts were interpreted as evidence of divine status by early humans.
The hypothesis that ancient astronauts existed and allegedly visited Earth is not taken seriously by most academics and archaeologists, which consider it to be pseudoarchaeological and/or unscientific, and has received no credible attention in peer reviewed studies. When proponents of the idea present evidence in favor of their beliefs, it is often distorted or fabricated.
Well-known ancient astronauts proponents in the latter half of the 20th century who have written numerous books or appear regularly in mass media include Erich von Däniken, Zecharia Sitchin, Robert K. G. Temple, Giorgio A. Tsoukalos, David Hatcher Childress and Peter Kolosimo.