What happens when we go to sleep? Neil deGrasse Tyson and co-hosts Chuck Nice and Gary O’Reilly break down the mystery of why we sleep, time dilation in dreams, circadian rhythms, and sleeping in space with neuroscientist Matt Walker. Why did our need for sleep survive evolution? We explore the evolution of sleep and why we even need to sleep at all. Do all animals sleep? Learn about Nathaniel Klietman’s cave study, our 24-ish hour sleep cycle, and what the definition sleep even is. Does the early bird really get the worm? What goes on in the body while we sleep? Discover the syphonic pulsing of brain waves that occurs in non-REM sleep and how REM sleep looks similar to waking. We discuss Alzheimer's relationship to sleep and new technology to manipulate sleep brain waves. Could you use technology to supercharge sleep so you could sleep for shorter periods? Can you really “catch up” on sleep? We explore the relationship between dreams and time and whether time really does move slower in the dream world. How similar is sleep to a psychotic break? We discuss the hallucinations and premonitions in sleep and do a statistical analysis of Gary’s premonitions. Is there snoring in space? Find out about what makes sleeping in space tricky and whether Neil would be a good subject for a sleep study. Thanks to our Patrons Micheal Unwin, Vijay Krishnan, Leroy Gutierrez, alycia allen, Hilary Rush, Kira Lesser, and Daryl Sawyer for supporting us this week. NOTE: StarTalk+ Patrons can listen to this entire episode commercial-free. Get the NEW StarTalk book, 'To Infinity and Beyond: A Journey of Cosmic Discovery' on Amazon: https://amzn.to/3PL0NFn 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 Timestamps: 00:00 - Introduction: Matt Walk Sleep Expert 3:38 - Why Do We Need Sleep? 05:26 - Evolving to Sleep & The Animal Kingdom 08:30 - Circadian Rhythms & Mammoth Cave 12:28 - Chronotypes: Early Birds & Night Owls 15:18 - What Happens When We Sleep? 18:42 - Mental Health & Dementia 21:19 - Can You Artificially Supercharge Your Sleep? 23:21 - Can You “Catch Up” On Sleep? 25:49 - Time Dilation in Dream Sleep 29:31 - Premonitions from Dreams 32:45 - Sleep & Psychosis 34:35 - Sleeping in Space 40:24 - Neil’s Sleep