Ancient astronaut is a term used to describe the theory that extraterrestrial beings visited Earth in the distant past and played a role in the development of human civilization. Some alternative terms for ancient astronaut include the ancient astronaut theory, paleocontact, ancient aliens, and ancient extraterrestrials. Other related concepts include the idea of a lost civilization, such as Atlantis, and the concept of panspermia, which suggests that life on Earth may have been seeded by microbial life from other planets. While the ancient astronaut theory remains controversial and largely unsupported by scientific evidence, it continues to capture popular imagination and inspire creative works such as books, films, and television programs.