There's a plausible chance that we may be alone in the galaxy right now. But the odds that the galaxy has never, and will never, host other civilizations is far less likely. Today we explore the possibility of communicating through time, and how such a feat might be accomplished. You can now support our research program and the Cool Worlds Lab at Columbia University: https://www.coolworldslab.com/support Thank-you to Kevin Clark, Tom Widdowson, Denny Smith, Stephanie Hackley, Kolos Kantor, Patrick Herman, Abel Aganbegyan, Claudio Bottaccini, Daniel Brunk, Scott Fincher & James Kindred for their support and especially to Executive Producers Mark Sloan, Laura Sanborn & Douglas Daughaday. References: ► Freitas & Valdes (1999), "The Search for Extraterrestrial Artifacts (SETA)", JBIS, 36, 501: https://ui.adsabs.harvard.edu/abs/1983JBIS...36..501F/abstract ► Luc Arnold (2005), "Transit Lightcurve Signatures of Artificial Objects", ApJ, 627, 534: https://arxiv.org/abs/astro-ph/0503580 ► Jeanna Bryner (2010), "Odds of Life on Newfound Earth-Size Planet '100 Percent,' Astronomer Says", Space.com: https://www.space.com/9225-odds-life-newfound-earth-size-planet-100-percent-astronomer.html ► David Kipping (2020), "An Objective Bayesian Analysis of Life's Early Start and Our Late Arrival", PNAS, 117, 11995: https://arxiv.org/abs/2005.09008 ► Denis Chow (2011), "On the Moon, Flags & Footprints of Apollo Astronauts Won't Last Forever", space.com: https://www.space.com/12846-apollo-moon-landing-sites-flags-footprints.html ::Video clips used:: ► Intro clip are images from NASA's EPIC DSCOVR mission, interpolated by BlueTurn: https://youtu.be/Mm8L6Hm6c-g ► Stars time lapse by Ben Vegel: https://youtu.be/Wl2sDEpjqQI ► Radio teleascope timelapse by Alex Cherney and CSIRO: https://youtu.be/1hawK5JwVfY ► NASA/JPL-Caltech/T. Pyle (SSC-Caltech) http://www.spitzer.caltech.edu/video-audio/728?limit=20&page=1 ► Galaxy fly through animation by AA VFX: https://youtu.be/Sd