Into the Impossible With Brian Keating Timescapes Make Dark Energy Irrelevant! (ft. David Wiltshire) [Ep. 500]
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Jun 30, 2025 In this engaging discussion, physicist David Wiltshire introduces his groundbreaking Timescape cosmology model, challenging conventional views of dark energy and cosmic acceleration. He explores how the varying passage of time in different regions of the universe might create the illusion of these phenomena. Wiltshire delves into Mach's Principle, gravitational time dilation, and their implications for understanding the universe's expansion, suggesting a radical reevaluation of dark energy's role. This conversation is a must-listen for those intrigued by the evolving landscape of cosmological theory.
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Timescape Model and Cosmic Time
- The Timescape model challenges the assumption of a single cosmic time by introducing a relativity of cosmological time depending on matter distribution.
- This explains how differential gravitational time dilation in voids versus walls can mimic cosmic acceleration without dark energy.
Time Runs Faster in Voids
- Gravitational time dilation causes clocks in denser regions to run slower than those in cosmic voids with less matter.
- This makes void regions' clocks effectively run faster, providing a new perspective on cosmic expansion history.
Void Dominance Creates Acceleration Illusion
- The apparent cosmic acceleration coincides with the time when voids dominate the universe’s volume, altering average clock rates.
- The illusion of acceleration arises from applying a homogeneous model to a universe with varied expansion rates and clocks.