There is a disagreement in measurements of the Hubble constant often referred to as The Crisis in Cosmology. One way to solve it is to observe redshift drift. However, it requires lengthy observations. But my guest, Dr Geraint Lewis, has a hack up his sleeve — gravitational lensing.

Redshift Drift story on Universe Today:
https://www.universetoday.com/162845/...
The Redshift Difference in Gravitational Lensed Systems: A Novel Probe of Cosmology:
https://arxiv.org/abs/2308.07529

Dr Geraint Lewis' website: https://www.geraintflewis.com/
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00:00:00 Intro
00:01:41 Understanding the expansion of the Universe
00:03:10 Hubble Tension and Crisis in Cosmology
00:05:53 Cosmic ladder of distances
00:17:30 CMB measurements
00:24:47 The Boring Solution
00:31:10 The Exciting Solution
00:37:25 Red Shift Drift
00:48:05 Time machine for free
00:54:14 Perfect solution with unlimited funds
00:57:05 Advice for young astronomers
01:03:44 Outro

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