The Deep Dive

Cosmology in Crisis


Listen Later

Discussing the persistent cosmological puzzle known as the Hubble Tension, which is the significant discrepancy between the universe's expansion rate (H₀) measured by local, late-time observations (like those from the Hubble and James Webb Space Telescopes using Cepheid variables and supernovae) and the lower rate predicted by early-time observations of the Cosmic Microwave Background (CMB), interpreted within the standard Lambda-CDM (ΛCDM) model. Research investigating this tension involves complex calculations using "standard rulers," such as the sound horizon scale, and evaluating numerous theoretical alternatives beyond ΛCDM, including models featuring Early Dark Energy (EDE), modified gravity, or extra relativistic particles. Crucially, recent results from the James Webb Space Telescope have affirmed the accuracy of the local measurements, strengthening the argument that new physics, rather than measurement error, may be required to resolve this fundamental crisis in cosmology. This highlights that while various models can alleviate the tension to varying degrees, no consensus solution has been found.

...more
View all episodesView all episodes
Download on the App Store

The Deep DiveBy FlyingFree