What if everything we know about the universe’s expansion is wrong? David Wiltshire offers a radical perspective on cosmic acceleration and dark energy, proposing that both might be illusions created by the varying passage of time in different regions of the universe. Wiltshire challenges the foundations of modern cosmology with his innovative Timescape model. We discuss the foundations of Einstein's theory of relativity, examining how time behaves differently in regions of high and low matter density. Wiltshire explains how this could alter our understanding of the universe’s expansion, potentially eliminating the need for dark energy altogether. His work revisits Mark’s Principle and its influence on cosmology, offering an alternative explanation for cosmic phenomena. This episode will captivate anyone interested in the future of cosmological theory, the mystery of dark energy, and the complex nature of time. Don’t miss out! — Key Takeaways:  00:00:00 Intro 00:01:36 David Wiltshire’s model and its implications 00:02:35 Mach's Principle and its influence on relativity 00:06:28 Gravitational time dilation and its implications 00:42:16 The cosmological equivalence principle 00:42:50 The Timescape Model and its predictions 00:43:53 The role of dark energy and the cosmological constant 00:53:43 The philosophical and psychological implications of Timescape 01:09:41 Outro  — Additional resources:  ➡️ Follow me on your fav platforms: ✖️ Twitter: https://twitter.com/DrBrianKeating  🔔 YouTube: https://www.youtube.com/DrBrianKeating?sub_confirmation=1  📝 Join my mailing list: https://briankeating.com/list  ✍️ Check out my blog: https://briankeating.com/cosmic-musings/  🎙️ Follow my podcast: https://briankeating.com/podcast  — Into the Impossible with Brian Keating is a podcast dedicated to all those who want to explore the universe within and beyond the known. Make sure to follow/subscribe so you never miss an episode! Learn more about your ad choices. Visit megaphone.fm/adchoices