We Thought Time Only Moved Forward. A Quantum Experiment Could Split It in Two.

Sign Up on Patreon to get access to the Space Time Discord! https://www.patreon.com/pbsspacetime Modern physics is weird. In quantum mechanics we have the Schrodinger’s cat thought experiment, a cat in a quantum superposition of being simultaneously alive and dead. And in relativity the twin paradox thought experiment, a space-faring twin ages less than her stay-at-home sibling. But what if we could combine these and send our quantum twin around the galaxy. Could we be simultaneously old and young? What would that tell us about the quantum nature of time? And would we need schrodinger birthday candles? Check out the Space Time Merch Store https://www.pbsspacetime.com/shop Sign up for the mailing list to get episode notifications and hear special announcements! https://mailchi.mp/1a6eb8f2717d/spacetime Search the Entire Space Time Library Here: https://search.pbsspacetime.com/ Hosted by Matt O'Dowd Written by Richard Dyer & Matt O'Dowd Post Production by Leonardo Scholzer Directed by Andrew Kornhaber Associate Producer: Bahar Gholipour Executive Producer: Andrew Kornhaber Executive in Charge for PBS: Maribel Lopez Director of Programming for PBS: Gabrielle Ewing Assistant Director of Programming for PBS: Mike Martin Spacetime is a production of Kornhaber Brown for PBS Digital Studios. This program is produced by Kornhaber Brown, which is solely responsible for its content. © 2026 PBS. All rights reserved. End Credits Music by J.R.S. Schattenberg: https://www.youtube.com/user/MultiDroideka Space Time Was Made Possible In Part By: Big Bang Alexander Tamas Filip Rolenec Juan Benet Kenneth See Mark Rosenthal MATTHEW OCKO Morgan Hough Peter Barrett Vinnie Falco Supernova Ethan Cohen Glenn Sugden Grace Biaelcki Justin Lloyd Mark Heising Rad Antonov Shaun Williams Stephen Wilcox Tristan Lucian Claudius Aurelius Tyacke Hypernova Daniel Muzquiz Alex Kern Ben Delo Chuck Zegar Dean Galvin Donal Botkin Gregory Forfa Jeff White John R. Slavik Massimiliano Pala PAUL C PEDERSEN Scott Gorlick Scott Gray Spencer Jones Vlad Shipulin Zachary Haberman Антон Кочков Gamma Ray Burst Jason Bowen Aaron Pinto Almog Cohen Arko Provo Mukherjee Austin Richards Ayden Miller Bert Whetstone Bradley Jenkins Bradley Ulis Brandon Lattin Cal Harrington Cal Stephens Cali Chuck Chris Liao Christopher Wade Collin Dutrow Craig Falls Craig Stonaha Dan Warren Daniel Donahue Daniel Jennings Darrell Stewart David Giltinan David Johnston Diana S Polijar Donovan King Doyle Vann Eric Kiebler Eric Raschke Eric Schrenker Faraz Khan Frederic Simon Harsh Khandhadia Isaac Suttell James Trimmier Jeb Campbell Jeff Harris Jeremy Soller Jerry Thomas jim bartosh John Anderson John De Witt John Funai John H. Austin, Jr. John Mieras USN Ret Joseph Salomone Junaid Ali Justin Zheng Kacper Cieśla Kent Durham Koen Wilde Kurtis Kemple Kyle Atkinson Lori Ferris Marcelo Garcia Marion Lang Mark Daniel Cohen Mark Delagasse Matt Kaprocki Matthew Johnson Michael Barton Michael Clark Michael Lev Michael Purcell Michael Spallino Mikk Mihkel Nurges Nicolas Katsantonis Nils Anderson Onemind Paul Wood Reuben Brewer Richard Steenbergen Robert DeChellis Ross Kennedy Ross Story Russell Moore SamSword Sandhya Devi Sean Owen Shane Calimlim Terje Vold Terrance Cennon Thomas Dougherty Tybie Fitzhugh WILLIAM HAY III Zac Sweers