Is there life on other planets? Are UFOs evidence of such life? Astrophysicist Adam Frank joins Julian Zelizer and Sam Wang to discuss his research of technosignatures — signs of past or present use of technology on other planets — and the search for evidence of life outside Earth.

Adam Frank is professor of physics and astronomy at the University of Rochester. He's a regular contributor to NPR's All Things Considered, and he occasionally writes for The New York Times. Last year, he and several of his colleagues were awarded a grant from NASA to fund the study of technosignatures.