Astronomer Seth Shostak thinks that if alien intelligence is out there, we'll know it when we see it.Podcast produced by David Levin. NOVA is produced by WGBH in Boston. Funding for NOVA is provided by David H. Koch, the Howard Hughes Medical Institute, the Corporation for Public Broadcasting, and public television viewers.Hear other experts describe what intelligence means to them. Visit us online at pbs.org/nova