Lex Fridman Podcast

Podbit · Lex Fridman Podcast

#497 – Biggest Mysteries in Physics: Antimatter, Dark Energy & ToE – Don Lincoln

Explore episode May 29, 2026
Science
The Speed of Light Is a Speed Limit of Spacetime Itself

#497 – Biggest Mysteries in Physics: Antimatter, Dark Energ… · May 29, 2026 Science

The speed of light isn't an arbitrary speed limit — it's the speed at which anything travels through spacetime. Particle physicists have directly confirmed it: particles decaying into photons while moving at 95% the speed of light still produce photons that travel at exactly c, not 1.95c. Einstein's second postulate is experimentally rock-solid.

Where this was said

Einstein, special relativity, and general relativity

At 27:10 · chapter starts 23:23

Einstein's 1905 miracle year and Minkowski's spacetime, the universality of the speed of light as a postulate and how particle physicists have directly measured it.

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