2016-08-19 00:49 thomas.godart Is it irrational to believe in aliens? Is It Irrational to Believe in Aliens? | Space Time | PBS Digital Studios play_circle_filled YouTube https://youtu.be/XAU9ofjcx-Y labelPBS Space Time check_box_outline_blank labelalien check_box_outline_blank labelDrake equation check_box_outline_blank labelFermi paradox check_box_outline_blank labelNick Bostrom check_box_outline_blank labelinteresting check_box