Patreon: https://www.patreon.com/seanmcarroll Blog post with audio player, show notes, and transcript: https://www.preposterousuniverse.com/podcast/2025/05/26/316-niayesh-afshordi-and-phil-halper-on-the-big-bang-and-before/ Einstein's general theory of relativity, plus some reasonable assumptions about the universe and what it's made of, has a remarkable implication: that as we trace cosmic evolution into the far past, we ultimately hit a singularity of infinite density and curvature, the Big Bang. Did that really happen? Einstein's theory is classical, after all, and the world is quantum. And whose to say what assumptions are reasonable? Niayesh Afshordi and Phil Halper have written a new book, Battle of the Big Bang: The New Tales of Our Cosmic Origins, that surveys all of the mind-bending possibilities. Niayesh Afshordi received a Ph.D. in astrophysics from Princeton University. He is currently a professor of physics and astronomy at the University of Waterloo, and associate faculty in the cosmology and gravitation group at the Perimeter Institute for Theoretical Physics. Phil Halper is a science communicator and a fellow of the Royal Astronomical Society. His astronomy images have been featured in major media outlets including The Washington Post, the BBC, and The Guardian, and he has published several papers in peer-reviewed journals. Mindscape Podcast playlist: https://www.youtube.com/playlist?list=PLrxfgDEc2NxY_fRExpDXr87tzRbPCaA5x Sean Carroll channel: https://www.youtube.com/c/seancarroll #podcast #ideas #science #philosophy #culture