In Theory with Janna Levin

About This Episode

If something is possible, has the universe tried it? Are all physical possibilities inevitable? Neil deGrasse Tyson sits down with theoretical astrophysicist Janna Levin to launch “In Theory,” a new StarTalk series celebrating the weird, wacky theories of the universe and the theorists who chase them. Out on YouTube October 29, 2026!

What if nature has already tried every experiment the laws of physics allow? We explore whether every solar system combination has been attempted, if our big bang is the only big bang, and if there are multiple universes, do they collide and overlap? We discuss why theorists sometimes wait centuries for vindication and whether the laws of physics were just a roll of the dice.

Are we pre-Copernican for the universe? We discuss we’re not even made of the stuff that makes up most of the cosmos, and Neil and Janna imagine what dark matter beings would make of us. How long would it take dark matter scientists to notice the matter universe? Next, theories nobody saw coming: surprise particles, Schwarzschild’s black hole solution from the front lines, Einstein’s doubts, dark matter & energy, Newton, Eddington’s eclipse, and the planet Vulcan. Is the universe actually knowable?

They ask whether relativity must nest inside a quantum theory of gravity and whether the universe is only describable statistically. Finally, wormholes, negative energy, conjectures like chronology protection, cosmic origami, and what to do when a theory’s predictions can’t be found in the universe. Plus, what does it mean to make a prediction that can’t be found in the universe?

Thanks to our Patrons Elamar, Natalia Nelicheva, Kyron Laskosky, Stanley Tai, Jan, Chris Tringali, Nikki Tea, Jay Kapadia, Sean Moran, SnakeSurfer, Roddie, Sam Sillmon, Graham West, Ben Fisk, ChexVC, aitor clemente ramos, Max Forkel, George Fox, and HKRDiary for supporting us this week.

NOTE: StarTalk+ Patrons can listen to this entire episode commercial-free.