Transcript: Carl Sagan was the first astronomer to attain widespread acclaim in the era of TV and the popular culture. He spent most of his career at the University of Cornell where he was a respected planetary scientist and editor of the main journal of planetary science, Icarus. He was...

Transcript: SETI, the Search for Extraterrestrial Intelligence, is a small subfield of astronomy. It doesn’t get most of the astronomy funding, and some astronomers even disapprove of it. SETI seeks to set aside speculation about intelligent life in the universe and conduct the experiment, to...

Transcript: The very limited evidence that we have is consistent with the supposition that microbial life is quite common in the universe whereas intelligent life is quite rare. Evidence in favor of microbial life being potentially common is the fact that carbon, nitrogen, and oxygen, the...