Do you believe in UFOs? (Beginner)

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If you mean alien spacecraft visiting Earth, then the answer is no. There are probably many, many civilizations in the universe, but the distances between them are just, well, astronomical. Interstellar space travel is not likely to be economical for any civilization recognizable as such. Aside from that, there has never been any physical evidence of alien spacecraft on Earth, or indeed, reliable evidence of any kind.

The page was last updated June 27, 2015.

About the Author

Dave Kornreich

Dave was the founder of Ask an Astronomer. He got his PhD from Cornell in 2001 and is now an assistant professor in the Department of Physics and Physical Science at Humboldt State University in California. There he runs his own version of Ask the Astronomer. He also helps us out with the odd cosmology question.