“Ancient astronauts” (or “ancient aliens”) refers to the pseudoscientific idea 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, and religions. 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.

Proponents of the ancient astronaut hypotheses often maintain that humans are either descendants or creations of extraterrestrial intelligence (ETI) who landed on Earth thousands of years ago. An associated idea is that humans evolved independently, but that much of human knowledge, religion, and culture came from extraterrestrial visitors in ancient times, in that ancient astronauts acted as a “mother culture”. Some ancient astronaut proponents also believe that travelers from outer space, referred to as “astronauts” (or “spacemen”) built many of the structures on Earth (such as Egyptian pyramidsand the Moai stone heads of Easter Island) or aided humans in building them.

Various terms are used to reference claims about ancient astronauts, such as ancient aliens, ancient ufonauts, ancient space pilots, paleocontact, astronaut- or alien gods, or paleo- or Bible-SETI (search for extraterrestrial intelligence).

Book of Genesis and Book of Enoch

The Book of Genesis, Chapter 6 verses 1-2 and 4, states:

When human beings began to increase in number on the earth and daughters were born to them, the sons of God saw that the daughters of humans were beautiful, and they married any of them they chose….The Nephilim were on the earth in those days—and also afterward—when the sons of God went to the daughters of humans and had children by them.— Genesis 6:1–4 (New International Version)

Many Christians consider these groups to be the different families of Adam and Eve’s children. Another interpretation is that the Nephilim are the children of the “sons of God” and “daughters of humans”, although scholars are uncertain. The King James Version translates “Nephilim” as “giants” (or Gibborim). Ancient Astronaut theorists argue that Adam and Eve ate of the forbidden fruit in order “to be godlike”, and this was the first step in human evolution. Hypothesis proponents argue further that the biblical tree of knowledge is a metaphor for the human DNA sequence.

The first part of the apocryphal Book of Enoch expands and interprets Genesis 6:1: that the “sons of God” were a group of 200 “angels” called “Watchers”, who descended to Earth to breed with humans. Their offspring are the Nephilim, “giants” who “consumed all the acquisitions of men”. When humans could no longer sustain the Nephilim, they turned against humanity. The Watchers also instructed humans in metallurgy and metalworking, cosmetics, sorcery, astrology, astronomy, and meteorology. God then ordered the Watchers to be imprisoned in the ground, and created the Great Flood (or the numerous Deluge myths) to rid Earth of the Nephilim and of the humans given knowledge by the Watchers. To ensure humanity’s survival, Noah is forewarned of the oncoming destruction. Because they disobeyed God, the book describes the Watchers as “fallen angels”.

Some ancient astronaut proponents argue that this story is a historical account of extraterrestrials visiting Earth, called Watchers because their mission was to observe humanity. Some of the extraterrestrials disobeyed orders; they made contact with humans, cross-bred with human females, and shared knowledge with them. The Nephilim were thus half-human-half-extraterrestrial hybrids.

Chuck Missler and Mark Eastman argue that modern UFOs carry the fallen angels, or offspring of fallen angels, and that “Noah’s genealogy was not tarnished by the intrusion of fallen angels. It seems that this adulteration of the human gene pool was a major problem on the planet earth”.

Von Däniken also suggests that the two angels who visited Lot in Genesis 19 were ancient astronauts, who used atomic weapons to destroy the city of Sodom.

Marc Dem reinterprets the Book of Genesis by writing that humanity started on another planet and that the God of the Bible is an extraterrestrial…