What is the International Date Line? Neil deGrasse Tyson and comedian Chuck Nice break down the history and purpose of the IDL. How do we know we needed a date line? Find out how the need for an international date line was discovered and why it was an accident. Where did we decide to put the date line? Plus, Chuck questions the existence of Mountain Time. Get the NEW Cosmic Queries book (5/5 ⭐s on Amazon!): https://amzn.to/3dYIEQF Support us on Patreon: https://www.patreon.com/startalkradio FOLLOW or SUBSCRIBE to StarTalk: Twitter: http://twitter.com/startalkradio Facebook: https://www.facebook.com/StarTalk Instagram: https://www.instagram.com/startalk About StarTalk: Science meets pop culture on StarTalk! Astrophysicist & Hayden Planetarium director Neil deGrasse Tyson, his comic co-hosts, guest celebrities & scientists discuss astronomy, physics, and everything else about life in the universe. Keep Looking Up! #StarTalk #neildegrassetyson 00:00 - The international date line is weird 02:00 - Circumnavigation & Time 08:07 - Observer Bias 11:40 - IDL Placement