In this video, Neil deGrasse Tyson discusses the mysteries of our universe and secret alien communications with 'geek-in-chief', Dr. Charles Liu. What's really causing the expansion of the universe? Dr. Liu suggests alternatives to Dark Matter, including the possibility that our universe is just a bubble in a larger universe. Why is gravity so weak? Dr. Charles Liu goes into depth about the mysteries of the Gravitron and how to square concepts from general relativity with quantum mechanics. How does time behave while approaching the speed of light? Could the fabric of spacetime be weaved by wormholes? Should we fear AI? Dr. Charles Liu gets deep as he questions the way humans value themselves in a future dominated by AI. What skills do we need to learn to retain our value in the workforce. Is there life elsewhere in the universe? Are aliens encrypting their messages to hide from us? Neil and Charles ponder deep questions about potential alien ancestors and extraterrestrial contact. From an episode of StarTalk: Special Edition, 'Lost in Translation: Encrypted Alien Messages': https://www.youtube.com/watch?v=NhsY0ClaBTM 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 0:00 - What's Causing Cosmological Expansion? 0:54 - Gravity & Quantum Field Theory 5:27 - The Fabric of Spacetime 7:13 - Should We Fear AI? 8:11 - Are Aliens Encrypting Their 9:11 - Is There Life Elsewhere in the Universe? 10:01 - Fossil Fuels