Physicist Jenny Wagner (@GravityGrinch) joins us for a conversation about just how much dark matter we really need. Right now, the most popular cosmological models require vast quantities of matter and energy to be in the "dark sector," an exotic substance that affects what we see in our telescopes, but cannot (yet) be directly detected by any of our instruments. Wagner's issue is that this "dark" status quo might not be necessary. Currently, it is invoked to account for the gap between what we see when we look through our telescopes, and what we expected to see if our theories about the evolution of the universe were correct. Dark matter and dark energy bridge this gap. but Wagner openly wonders - what if it's our theories about the evolution of the universe that are wrong? Jenny's blog: https://thegravitygrinch.blogspot.com/ PATREON https://www.patreon.com/c/demystifysci PARADOX LOST PRE-SALE: https://buy.stripe.com/7sY7sKdoN5d29eUdYddEs0b HOMEBREW MUSIC - Check out our new album! Hard Copies (Vinyl): FREE SHIPPING https://demystifysci-shop.fourthwall.com/products/vinyl-lp-secretary-of-nature-everything-is-so-good-here Streaming: https://secretaryofnature.bandcamp.com/album/everything-is-so-good-here PARADIGM DRIFT https://demystifysci.com/paradigm-drift-show 00:00 Go! Grounding Cosmology in What We Can Actually Observe 00:01:57 Data First: Separating Physics from Statistical Assumptions 00:09:32 How Dark Matter Falls Out of the Models We Choose 00:14:38 Zwicky, Coma, and the Birth of the Missing Mass Problem 00:20:58 Bound or Just Passing Through? The Cluster Stability Debate 00:25:22 Two Missing Mass Problems Merge Into One Story 00:33:40 Lambda: The Cosmological Constant and the Rise of Dark Energy 00:45:09 Why Simple Models Stuck, and the Underdetermination Trap 00:52:04 Average Density and the Roots of Statistical Cosmology 01:01:05 Where Cosmology and Astrophysics Split 01:09:12 Causality From Inside the Universe 01:18:21 One Snapshot of the Cosmos, and What Webb Adds 01:24:48 Where the Dark Matter Doubt Began: Lensing's Fine Print 01:32:20 Meeting MOND and the Bullet Cluster Up Close 01:39:24 Revisiting General Relativity at Galactic Scales 01:44:49 Gravity as Geometry, and the Cause We Still Can't Name 01:51:15 The Case for Cosmology Without a Dark Sector 01:56:21 Why Equations Take Their Form: Higgs vs. Dark Matter 02:03:52 Necessary or Merely Sufficient? Bias in the Field 02:08:23 Storytelling, Awe, and the Pull of Exotic Explanations 02:13:39 Determinism, Free Will, and the Limits of Reductionism 02:20:07 What's Next: Curvature, and the Gravity Grinch #DarkMatter #Cosmology #GravitationalLensing #DarkEnergy #Astrophysics #GeneralRelativity #Physics #Spacetime #Gravity MERCH: Rock some DemystifySci gear : https://demystifysci-shop.fourthwall.com/ AMAZON: Do your shopping through this link: https://amzn.to/3YyoT98 DONATE: https://bit.ly/3wkPqaD SUBSTACK: https://substack.com/@UCqV4_7i9h1_V7hY48eZZSLw@demystifysci RSS: https://anchor.fm/s/2be66934/podcast/rss MAILING LIST: https://bit.ly/3v3kz2S SOCIAL: - Discord: https://discord.gg/MJzKT8CQub - Facebook: https://www.facebook.com/groups/DemystifySci - Instagram: https://www.instagram.com/DemystifySci/ - Twitter: https://twitter.com/DemystifySci MUSIC: -Shilo Delay: https://g.co/kgs/oty671