Quote · Lex Fridman Podcast
#497 – Biggest Mysteries in Physics: Antimatter, Dark Energy & ToE – Don Lincoln
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Dark matter
At 2:47:50 · chapter starts 2:22:23
Three observational pillars for dark matter; Bullet Cluster and Dragonfly galaxies as key evidence; WIMP searches and why 30 years of direct detection experiments have found nothing; dark matter is 5× ordinary matter. [1] — Don Lincoln "Dark matter is five times more abundant than ordinary matter and is supported by three independent lines of astronomical evidence: galaxy r…" 2:35:57
Dark matter is five times more abundant than ordinary matter and is supported by three independent lines of astronomical evidence: galaxy rotation curves, galaxy cluster dynamics, and gravitational lensing. The Bullet Cluster and Dragonfly galaxies strongly suggest it's real. But after 30 years of searching, physicists have found no direct particle evidence.
When two galaxy clusters collide, the gas clouds collide and stop, but any dark matter passes straight through. The Bullet Cluster shows gravitational lensing distortions at the locations of the galaxies — not the gas. That geometry is only explicable if unseen mass accompanied the galaxies. It's Lincoln's strongest reason for believing dark matter is real.
Dark matter is five times more prevalent than all ordinary (baryonic) matter in the universe, yet its fundamental nature remains completely unknown.
