Andrew Strominger: Theoretical physicist at Harvard and a founder of the Black Hole Initiative. A pioneer of string theory whose work spans the holographic principle, black hole information, and the quantum structure of black holes; he co-authored the 'soft hair on black holes' paper with Stephen Hawking.
What this episode covers
Strominger and Lex Fridman explore the deepest puzzles of modern physics, starting with what a black hole actually is and why even light cannot escape. The conversation moves through quantum gravity, the standard model, and string theory as a 'stepping stone' toward unifying quantum mechanics and general relativity. Strominger explains the holographic principle, how black holes store information on their surface area, and his collaboration with Hawking showing that black holes retain subtle 'soft hair' imprints. He also discusses photon rings around black holes, the Event Horizon Telescope image of M87, and the possibility of learning about black holes by treating them as hall-of-mirrors reflectors. The talk closes on emergent time and space, AI in physics, the origin of the universe, alien civilizations, and the responsibility of scientists.
Recommended on this episode
Interstellar
Christopher Nolan
“there's a wonderful movie um Interstellar and um in that movie you know Kip Thorne of course is a great theoretical physicist”— Andrew Strominger
Also referenced (named, not recommended)
A New Kind of Science
Stephen Wolfram
“he wrote a book A New Kind of Science um basically hinting at which a lot of people offended”— Andrew Strominger
Dreams of a Final Theory
Steven Weinberg
“so Weinberg has this book called dreams of a final Theory yeah and I had this conversation with him”— Andrew Strominger
The Hitchhiker's Guide to the Galaxy
Douglas Adams
“maybe you can ask it a question it'll be some kind of Hitchhiker's Guide to the Galaxy type answer”— Andrew Strominger
Big reveals from this episode
- Strominger says Einstein wrote a paper 25 years after predicting black holes arguing they don't exist, and jokes he wouldn't pass a student who turned that in.
- Bets the farm that 100 years from now string theory will be seen as a stepping stone, not a final theory, and admits he doesn't believe it himself yet.
- Explains the holographic principle: a black hole's information is proportional to its surface area, not its volume.
- Reveals that if string theory had not reproduced the Bekenstein-Hawking entropy, string theory itself would have been proven inconsistent.
- Recalls Hawking turning down tea with Lady Gaga so they could spend another hour on their paper.
- Says he honestly doesn't know if a theory of everything exists, and is confident we won't reach it in his lifetime.
- States that time itself must ultimately be emergent, not fundamental.
- Describes a black hole as a mirror that lets you see an infinite number of delayed copies of yourself.
Worth remembering
- Earth's escape velocity is about 11 km/s; the Moon's is only about 7 km/s; a black hole's reaches the speed of light.
- Mercury's perihelion precesses once every 233 centuries versus Newton's predicted 231, the first crack in Newtonian gravity, measured by Le Verrier in 1859.
- The standard model has been confirmed against experiment to 16 decimal places, which Strominger has stenciled on his office door.
- The three simplest spacetimes are flat (Minkowski), negatively curved (anti-de Sitter), and positively curved (de Sitter).
- John Wheeler coined both the term 'black hole' and the phrase 'black holes have no hair.'
- A zero-energy 'soft' photon still carries angular momentum one, and a soft graviton angular momentum two, so they cannot simply be ignored.
- The Event Horizon Telescope's famous 'donut' image of M87 was captured in 2018 and presented in 2019.
- Ramanujan worked by guessing formulas and gathering a 'preponderance of evidence' rather than formal proofs.
- The episode ends with Heisenberg's line that the universe is not only stranger than we think, but stranger than we can think.