“A factory that can turn carbon nanotubes into a sheet a yard wide and long enough to stretch one-fourth of the way to the moon is not something you'll find at your local industrial park. That's the show-stopper for the space elevator. The ribbon.”

American astronomer and author

G. Seth Shostak is an American astronomer and author, best known as the senior astronomer for the SETI Institute. He has spent his career working in astronomy and public discussion of the search for life beyond Earth. His work at SETI places him at the center of research and outreach on extraterrestrial intelligence. As an author and scientist, he often writes and speaks about astronomy, the search for signals from other civilizations, and related questions about the universe.