Is anything real? Is time just a construct? On this episode, Neil deGrasse Tyson and comic co-host Matt Kirshen answer your far-out questions about black holes, dark matter, and the universe with astrophysicist Janna Levin. Could you surf gravitational waves? What is the universe expanding into? We visualize the expanding universe, the inside of atoms, and what it even means for particles to interact. Is everything just a form of energy? Is there a physical reality or are we all just perceiving ourselves in the moment? We dive into if time is a human construct. Is time fundamental to the universe? We explore models for the death of the universe and what would happen if nothing changed. Discover how time dilation works and whether gravity and velocity could cancel each other out. What does it mean to rotate between space and time? What is the temperature inside a black hole? Are they cold or hot? What happens when dark matter enters a black hole? We discuss Hawking radiation, gamma rays, and what a black hole really looks like. All that, plus, get our step-by-step guide on how to open up a wormhole and an invitation to 2005’s time traveler conference. Thanks to our Patrons Ivan Masjuk, c, Nathan Mitchell, Conner Kemmsies, Dustin Dewayne Hart, Kyle Reinsberg, Andrew Magri, Virginia Cohen, Cathleen Corrie, and David Claassen for supporting us this week. NOTE: StarTalk+ Patrons can watch or listen to this entire episode commercial-free. Get the NEW Cosmic Queries book (5/5 ⭐s on Amazon!): https://amzn.to/3dYIEQF Get Janna Levin’s ‘Black Hole Survival Guide’: https://amzn.to/3hUif8g 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 0:00 - Introduction 1:52 - Janna Levin’s Pioneer Works 3:33 - Can Black Holes Create Repulsive Gravity Waves? 8:51 - What Is The Universe Expanding Into? 13:24 - Is Everything Just A Form Of Energy? 17:27 - Social Media Plugs 18:29 - Is Time Just A Human Invention? 22:21 - Why Does Gravity Slow Time? 27:30 - Do Your Feet Age Quicker Than Your Head? 32:01 - Janna Levin’s Books 34:11 - Why Are Black Holes So Cold? 41:20 - Will A Black Hole Radiate Dark Matter? 43:00 - How Do We Open A Worm Hole? 47:13 - Closing Notes