StarTalk Radio Dark Universe Decoded with Katherine Freese
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Mar 17, 2026 Katherine Freese, theoretical physicist and cosmologist who studies dark matter and dark stars, joins to explore the dark universe. She explains paleo detectors that use ancient rocks, why xenon sits in underground labs, and how JWST findings relate to dark energy. Topics include WIMPs, axions, primordial black holes, dark stars, modified gravity, and detection strategies.
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Paleo Detectors Use Time Instead Of Volume
- Paleo detectors replace detector volume with geological time to increase dark matter sensitivity.
- Katherine Freese explains digging olivine-rich rocks kilometers underground preserves billion-year tracks that accumulate rare dark-matter or neutrino interactions.
Claims Of Changing Dark Energy Depend On Analysis
- Evidence for time-varying dark energy is debated and sensitive to analysis method.
- Freese and collaborator Yun Wang reanalyzed DESI-like data directly extracting dark energy density and found the slowing-acceleration claim weak.
Dark Stars Could Explain James Webb Mysteries
- Dark stars are early ordinary-matter stars powered by dark matter annihilation instead of fusion.
- Freese says they start near one solar mass, stay cool, accrete to ~10^6 solar masses, and could match James Webb early-bright candidates.
