If the multiverse exists, where does our universe end and another begin? Neil deGrasse Tyson and comic co-host Chuck Nice tackle a wide-ranging grab bag of fan questions covering bubble universes, the nature of now, fractals, Hoag's Object, and more. How do we tell when our universe ends and another begins? We explore the bubble universe model, where separate universes expand without overlapping, each potentially operating under different laws of physics. How can we test for another universe impinging on ours? Next we cover Neil’s favorite and least favorite astronomical words. Could Project Starshot's laser-propelled nanocraft reach Alpha Centauri before a more advanced mission launched decades later? Neil breaks down the math and how lightsails could be our most efficient way of accessing other star systems. Is there such a thing as a shared "now"? How does a rubber sheet visualization of gravity actually work in four dimensions? We discuss Hoag’s Object and how calculating chance alignments helped us discover binary star systems. Are fractals the key to understanding everything in the universe or are they more entertaining than useful? How does an expanding universe affect time? Did time pass differently in the past? Plus, what did the sky look like when the cosmic microwave background was visible light? Thanks to our Patrons Joan Kirk, Robert Roberts, Mike Holland, Manickore, Zaki Imani, Christopher Johnson, Seb, Annette Hinkle, Bruce Davis, Geoff Hansen, Matthew Binggeli, Michael Greer, steph, Jo, Laurie Rieman, Monneke King, TakeOffYourPantsAndJacket, Catharine Hula, John, Mike, Jordan Jefferson, Bruce, Burç Ayata, Armon Jackson, and Sami Röksä for supporting us this week. Get the NEW StarTalk book, 'Lost in Space: 5,000 Facts for Navigating the Universe' on Amazon: https://amzn.to/4cCD19e Order Take Me to Your Leader here 👇 https://www.simonandschuster.com/books/Take-Me-to-Your-Leader/Neil-deGrasse-Tyson/9781668249970 Check out our second channel, @StarTalkPlus 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! © 2026 Curved Light Productions. All rights reserved. STARTALK is a registered U.S. trademark of Curved Light Productions. Curved Light Productions also maintains rights in the A/legs design logo, STARTALK, STARTALK+, STARTALK PLUS in the U.S. and various countries throughout the world, and these and all other associated logos, marks, and trade dress are the property of Curved Light Productions. This video, including all audio, video, graphics, and accompanying materials, is the exclusive property of Curved Light Productions. No part of this video may be reproduced, distributed, publicly performed, transmitted, or used to create derivative works, in whole or in part, in any medium now known or hereafter devised, without the prior express written permission of Curved Light Productions. Unauthorized use, including reuploading, re-editing, or incorporation into third-party content, is a violation of United States and international copyright law and will be enforced. For licensing and permissions inquiries: licensing@startalkmedia.com #StarTalk #NeildeGrasseTyson