StarTalk Radio Solving the Crisis in Cosmology with Wendy Freedman
Sep 23, 2025
Wendy Freedman, a renowned observational astronomer known for her precision in measuring the universe's expansion, joins Neil deGrasse Tyson and Matt Kirshen. They delve into the intriguing Hubble tension, exploring discrepancies in the universe's estimated ages. Freedman shares insights on advanced methods and programs to measure cosmic distances, including the use of Cepheids and Type Ia supernovae. The discussion covers potential new physics and the implications of dark energy, making complex cosmological concepts accessible and engaging!
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Hubble Telescope's Design Purpose
- Hubble was designed to resolve a decades-long debate about the universe's age and expansion rate.
- Its mirror size was set specifically to measure Cepheids and settle the 50 vs 100 H0 argument.
What 'Hubble Tension' Means
- The Hubble tension compares local distance-based H0 (
73) with CMB-inferred H0 (67). - That small difference is significant because modern uncertainties are tiny and don't overlap.
When HST And WMAP Agreed
- Wendy recounts the early 2000s era when HST and WMAP gave consistent H0 values near 71–72.
- That consistency felt like a major triumph resolving earlier wide disagreements.
