Has the earth been visited by extraterrestrials? Are we alone? Despite no formal evidence for conscious life outside of earth, the belief that we are not alone has become more common among both scientists and everyday people. Listen as author Adam Kirsch talks to EconTalk host Russ Roberts about the urge to believe that there are sentient beings elsewhere in the universe and that these aliens want to connect with human beings. Topics discussed include why belief in extraterrestrials has become more mainstream, existential loneliness, religion, extinction, and Elon Musk's desire to get to Mars.