Ancient astronaut theory

The Ancient Astronaut Theory is a fringe theory that claims that the emergence of early human civilization was influenced by extraterrestrial interaction based around a few vague images in ancient sites. Some variations of this theory involve a technologically advanced Atlantean society. This theory is not considered valid by the vast majority of the academic community.

The Ancient Astronaut Theory in science fiction

Despite it's lack of academic credibility, it's romantic appeal makes it a popular feature in science fiction.

• The Stargate Franchise is based around this idea.
• In TNG "The Chase", the abundance of humanoid species in the galaxy is shown to be the result of "seeding" by ancient astronauts.