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What Janna Levin thinks about physics

@janna-levin · 24 positions · 0 changes of mind

Theoretical cosmologist, professor of physics and astronomy at Barnard College of Columbia University, and chief science officer of Pioneer Works.

Janna Levin did not write this page.

We collected these quotes from things they published elsewhere, and every quote links to where it was said. They have no account here and have not endorsed this site. Quotes are word for word; the short line under each one is our own restatement, not their wording. Their own site. Is this you? Claim it or ask us to remove it. Or tell us what is wrong here.

16 dated positions, 2025, in their own words. Our reading of what Janna Levin has said — not written or endorsed by them.

  1. Our readingBlack holes are not the same thing as dead stars; they are a more general and more fundamental phenomenon than the end state of a star.

    Their wordsBut then I think that there’s a confusion that dead stars, these very, very massive stars that die, are synonymous with the phenomenon of black hole. And it’s really not the case. Black holes are more general and more fundamental than just the death state of a star.

    ↗Janna Levin: Black Holes, Wormholes, Aliens, Paradoxes & Extra Dimensions | Lex Fridman Podcast #468youtube.com 1st of 24 in this recording

  3. Our readingA black hole is its event horizon, not the matter crushed to a point at the centre.

    Their wordsThe black hole is not the mass crushed to a point. The black hole is the event horizon. And the event horizon is really just a point in spacetime or a region at spacetime.

    ↗Janna Levin: Black Holes, Wormholes, Aliens, Paradoxes & Extra Dimensions | Lex Fridman Podcast #468youtube.com 2nd of 24 in this recording

  5. Our readingScience is agnostic about what it is used for: the same physics that explained why stars shine also built the bomb.

    Their wordsAnd that’s what I mean by science is agnostic. Right? It’s the same technology overcoming a critical mass, igniting thermonuclear fusion.

    ↗Janna Levin: Black Holes, Wormholes, Aliens, Paradoxes & Extra Dimensions | Lex Fridman Podcast #468youtube.com 3rd of 24 in this recording

  7. Our readingInside a black hole the singularity is not a place you could steer around; it is a moment in your future you can no more avoid than time itself.

    Their wordsIn other words, the singularity ends up in their future and they can no more avoid the singularity than they can avoid time coming their way. There’s no shenanigans you can do once you’re inside the black hole to try to skirt it.

    ↗Janna Levin: Black Holes, Wormholes, Aliens, Paradoxes & Extra Dimensions | Lex Fridman Podcast #468youtube.com 5th of 24 in this recording

  9. Our readingThe bigger the black hole, the less you would notice crossing its horizon, because curvature is harder to feel the larger it gets.

    Their wordsThat might surprise people. The bigger it is, the less noticeable it is that you’ve crossed the event horizon. One way to think about it is curvature is less noticeable the bigger it is.

    ↗Janna Levin: Black Holes, Wormholes, Aliens, Paradoxes & Extra Dimensions | Lex Fridman Podcast #468youtube.com 6th of 24 in this recording

  11. Our readingSupermassive black holes did not grow by merging smaller ones — there has not been enough time — they collapsed directly out of primordial matter.

    Their wordsWe don’t think that the universe has had enough time to make them from stars that just merge. We know that two black holes can merge and make a bigger black hole and then those can merge and make a bigger black hole. We don’t think there’s been enough time for that.

    ↗Janna Levin: Black Holes, Wormholes, Aliens, Paradoxes & Extra Dimensions | Lex Fridman Podcast #468youtube.com 7th of 24 in this recording

  13. Our readingWeightlessness, not weight, is the purest experience of gravity — what you feel sitting in a chair is atoms interfering.

    Their wordsTo be falling. That is the purest experience of gravity. The experience of gravity, unfettered, uninterrupted by atoms is weightlessness.

    ↗Janna Levin: Black Holes, Wormholes, Aliens, Paradoxes & Extra Dimensions | Lex Fridman Podcast #468youtube.com 8th of 24 in this recording

  15. Our readingA black hole is featureless in the way a fundamental particle is: charge, mass and spin are the whole of it, and no two differ in anything else.

    Their wordsSo they’re flawless in the sense that you can completely understand a black hole by looking at just its electric charge, its mass and its spin. And every black hole with that charge mass and spin is identical to every other black hole.

    ↗Janna Levin: Black Holes, Wormholes, Aliens, Paradoxes & Extra Dimensions | Lex Fridman Podcast #468youtube.com 10th of 24 in this recording

  17. Our readingInformation is not lost in a black hole; the paradox is a crisis handing us clues, not a sign that quantum mechanics fails.

    Their wordsI’m unhappy with that. I would not be happy with information loss. I love that it’s telling us that there’s this crisis because I do think it’s giving us the clues, and we have to take them seriously.

    ↗Janna Levin: Black Holes, Wormholes, Aliens, Paradoxes & Extra Dimensions | Lex Fridman Podcast #468youtube.com 11th of 24 in this recording

    quantum mechanics

  19. Our readingThere is a hard ceiling on how much information a volume can hold: try to exceed what fits on its surface and you simply make a black hole.

    Their wordsIf I tried to pack a lot of information into a volume, more information than I could pack, let’s say, on the surface of a black hole, I would simply make a black hole and I would find out, oh, I can’t have more information than I can fit on the surface.

    ↗Janna Levin: Black Holes, Wormholes, Aliens, Paradoxes & Extra Dimensions | Lex Fridman Podcast #468youtube.com 12th of 24 in this recording

  21. Our readingNobody really believes there is a firewall at the event horizon, but the firewall papers were what stopped the field from stalling.

    Their wordsI don’t think anyone really believes that at the event horizon you’ll find a firewall. But it did lead to things like the entangled wormholes embroidering a black hole, which was born out of an attempt to address the concerns that AMPS raised. So it did lead to progress.

    ↗Janna Levin: Black Holes, Wormholes, Aliens, Paradoxes & Extra Dimensions | Lex Fridman Podcast #468youtube.com 13th of 24 in this recording

  23. Our readingThe thing to give up in the information paradox is locality: keep the empty event horizon, and let things be connected non-locally by wormholes.

    Their wordsI’m going back to the vacuum. The empty space, the beautiful event horizon I’ll give up locality, meaning that I will allow things to be connected non-locally by a wormhole.

    ↗Janna Levin: Black Holes, Wormholes, Aliens, Paradoxes & Extra Dimensions | Lex Fridman Podcast #468youtube.com 14th of 24 in this recording

  25. Our readingThere may be no theory of quantum gravity to find, because gravity is not fundamental — it emerges at large scales out of quantum phenomena.

    Their wordsI think that this is suggesting that there might not be a theory of quantum gravity, that gravity will emerge at a macroscopic level, out of quantum phenomena. Now, we don’t know how to do that yet, but these are all hints.

    ↗Janna Levin: Black Holes, Wormholes, Aliens, Paradoxes & Extra Dimensions | Lex Fridman Podcast #468youtube.com 15th of 24 in this recording

  27. Our readingWormholes are not yet an engineering problem, but they sit entirely within the realm of plausible physics.

    Their wordsThat’s going to be really telling. So I’m not saying it’s simply an engineering problem, but it’s all within the realm of plausible physics, I think.

    ↗Janna Levin: Black Holes, Wormholes, Aliens, Paradoxes & Extra Dimensions | Lex Fridman Podcast #468youtube.com 19th of 24 in this recording

  29. Our readingGravitational waves should be mapped as sound rather than pictured: they ring spacetime in the range a human ear could hear.

    Their wordsSo the idea is that they’re closer to something that you would want to map as a sound, than it’s something as a picture.

    ↗Janna Levin: Black Holes, Wormholes, Aliens, Paradoxes & Extra Dimensions | Lex Fridman Podcast #468youtube.com 21st of 24 in this recording

  31. Our readingA self-respecting theoretical physicist kills most of their own ideas rather than waiting for somebody else to do it.

    Their wordsI totally agree. Sometimes I take too long to come to that conclusion, but I will proudly say, as most theoretical physicists should, that I kill most of my ideas myself.

    ↗Janna Levin: Black Holes, Wormholes, Aliens, Paradoxes & Extra Dimensions | Lex Fridman Podcast #468youtube.com 23rd of 24 in this recording