Janna Levin
Astrophysicist at Barnard College; wrote Black Hole Blues and How the Universe Got Its Spots, and directs sciences at Pioneer Works.
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What they believe
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A black hole is its event horizon, not the matter crushed to a point at the centre.
The 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.
youtube.comSaid 5 May 2025This on korrents
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Beliefs
Korrents What they believe 24 beliefs — each backed by an exact quote.
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Recent
A black hole is its event horizon, not the matter crushed to a point at the centre.
The 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 #468 Said 5 May 2025
Black 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.
But 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 #468 Said 5 May 2025
Science is agnostic about what it is used for: the same physics that explained why stars shine also built the bomb.
And 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 #468 Said 5 May 2025
Show 21 more
The world's scientists came to America because it was intellectually free, and they will stop coming if that freedom goes.
Absolutely. The world flocked here. And that won’t be the case if we no longer have intellectual freedom.
Janna Levin: Black Holes, Wormholes, Aliens, Paradoxes & Extra Dimensions | Lex Fridman Podcast #468 Said 5 May 2025
Inside 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.
In 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 #468 Said 5 May 2025
The bigger the black hole, the less you would notice crossing its horizon, because curvature is harder to feel the larger it gets.
That 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 #468 Said 5 May 2025
Supermassive black holes did not grow by merging smaller ones — there has not been enough time — they collapsed directly out of primordial matter.
We 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 #468 Said 5 May 2025
Weightlessness, not weight, is the purest experience of gravity — what you feel sitting in a chair is atoms interfering.
To 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 #468 Said 5 May 2025
The best scientists ask the simplest questions, because they never lie to themselves that they understand something they do not.
The best scientists I know often ask the simplest questions. First of all, there’s probably some confidence there, but also they’re never going to lie to themselves that they understand something that they don’t understand.
Janna Levin: Black Holes, Wormholes, Aliens, Paradoxes & Extra Dimensions | Lex Fridman Podcast #468 Said 5 May 2025
A 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.
So 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 #468 Said 5 May 2025
Information is not lost in a black hole; the paradox is a crisis handing us clues, not a sign that quantum mechanics fails.
I’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 #468 Said 5 May 2025
Nobody really believes there is a firewall at the event horizon, but the firewall papers were what stopped the field from stalling.
I 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 #468 Said 5 May 2025
The thing to give up in the information paradox is locality: keep the empty event horizon, and let things be connected non-locally by wormholes.
I’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 #468 Said 5 May 2025
There may be no theory of quantum gravity to find, because gravity is not fundamental — it emerges at large scales out of quantum phenomena.
I 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 #468 Said 5 May 2025
There 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.
If 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 #468 Said 5 May 2025
With more planets than stars in the Milky Way, it has become impossible to believe life was not sparked somewhere else, possibly within a few hundred light years of us.
It becomes impossible to imagine that life was not sparked somewhere else, in our Milky Way galaxy, and maybe even in our local neighborhood of the Milky Way galaxy, maybe within a few hundred light years of our solar system.
Janna Levin: Black Holes, Wormholes, Aliens, Paradoxes & Extra Dimensions | Lex Fridman Podcast #468 Said 5 May 2025
Looking for aliens who build things is a failure of imagination: the long-lived species we know of do not manipulate their environment at all.
So I think we’re very attached to imagining creatures like us, that manipulate technology, and I think we have to be way more imaginative if we’re going to really take seriously life in the universe.
Janna Levin: Black Holes, Wormholes, Aliens, Paradoxes & Extra Dimensions | Lex Fridman Podcast #468 Said 5 May 2025
The hardest step on the road from chemistry to us was multicellularity, and it was strictly a problem of energetics.
I would say, multicellularity which is strictly an energy problem, I think. Again, it’s just like can electrons flow the right way. And is it energetically favorable for multicellularity to exist because if it’s energetically expensive, it’s not going to succeed.
Janna Levin: Black Holes, Wormholes, Aliens, Paradoxes & Extra Dimensions | Lex Fridman Podcast #468 Said 5 May 2025
Wormholes are not yet an engineering problem, but they sit entirely within the realm of plausible physics.
That’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 #468 Said 5 May 2025
Calling dark matter and dark energy invented names for physicists' ignorance gets it exactly backwards: only extraordinary precision let us see that they are missing.
And so I would say, yes, we are just giving proxy names to things we don’t understand, but to dismiss that as some kind of, “Oh, they just don’t know…” It is actually quite the opposite.
Janna Levin: Black Holes, Wormholes, Aliens, Paradoxes & Extra Dimensions | Lex Fridman Podcast #468 Said 5 May 2025
Gravitational waves should be mapped as sound rather than pictured: they ring spacetime in the range a human ear could hear.
So 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 #468 Said 5 May 2025
A self-respecting theoretical physicist kills most of their own ideas rather than waiting for somebody else to do it.
I 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 #468 Said 5 May 2025
A discovery you can see your way through to is impossible to abandon, even out of a real fear that it will be misused.
I would find it impossible to not pursue a discovery that I could imagine my way through, if I can really see how to get there. I cannot imagine abandoning it for some other reason, fear that it would be misused, which is a real fear.
Janna Levin: Black Holes, Wormholes, Aliens, Paradoxes & Extra Dimensions | Lex Fridman Podcast #468 Said 5 May 2025
Everything we build — every proof, every Nobel Prize, every idea, even the AI — will eventually be erased, which is why the near term matters.
Eventually, I think it’s kind of hard to imagine, but yes, all of these Nobel Prizes, all of these mathematical proofs, all of these conversations, all of these ideas, all the influence we have on each other, even the AI, eventually will expire.
Janna Levin: Black Holes, Wormholes, Aliens, Paradoxes & Extra Dimensions | Lex Fridman Podcast #468 Said 5 May 2025
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Recommends rcmnd
rcmnd What they recommend 8 things — each backed by an exact quote.
Compiled by rcmnd.app, not by them: the quotes are theirs, and each links to the post it was copied from.
Recent
Loved The Ministry for the Future
I fully imagine that his Ministry for the Future—which opens with the most harrowing, unrelenting depiction of a deadly heatwave—will be the warning and plea needed for the world to actually create a Ministry for the Future.
jannalevin.substack.com 18 Aug 2026
Liked New York 2140
I can also attest that our NYC audience whooped at the high-paced descriptions of a partially submerged Manhattan in New York 2140.
jannalevin.substack.com 18 Aug 2026
Loved Mars trilogy
His seminal Mars trilogy is legendary and much loved.
jannalevin.substack.com 18 Aug 2026
Show 5 more
Loved Animal Farm
Loved The Road
there was one book that I think was kind of surprising that I think is an absolute masterpiece, which is “The Road.” And you might say, “In what sense is ‘The Road’ a science?” Well, first of all, Cormac McCarthy absolutely loves scientists and science, and you can feel this very subtle influence, and that book is… it’s a really remarkable, precise, stunning, ethereal, all of these things at once, and there’s no who, what, when or how. You might guess it’s a nuclear event that kicks off the book or… A lot of people know “The Road,” I think, from the movie, but really the book is magnificent
lexfridman.com 5 May 2025
Liked Time's Arrow
Martin Amis wrote a book that runs backwards, “Time’s Arrow.” I love some of his other books even more, but “Time’s Arrow” is pretty clever.
lexfridman.com 5 May 2025
Loved Never Let Me Go
Kazuo Ishiguro, who won the Nobel Prize, wrote “Remains of the Day,” probably most famously, his book “Never Let Me Go,” it’s unbelievable, totally devastating. Stunning.
lexfridman.com 5 May 2025
Recommends From Eternity to Here
And also our friend, Sean Carroll, has written a wonderful book called From Eternity to Here, which lays these issues out. And I think is a really nice read.
tim.blog 9 Jul 2020
Where they publish
Site jannalevin.com Her site: the books, talks and writing. Has a feed.
Link verified 20 Sept 2026.
x.com @JannaLevin Their X account.
Recent
- Yeah, wormholes are hard to maintain. Or form. 1 Nov 2026
- Kicking it with my pal NdGT, talking Einstein 1 Nov 2026
- Tune in. Had a chance to chat with the founding director of the EHT consortium, Shep Doeleman -- also my dear friend -- on the Joy of Why 29 Oct 2026
Show 15 more
- My pal Neil de Grasse Tyson invited me on the StarTalk podcast to rap about a new spinoff I’m hosting on his channel: In Theory — a miniseries on the most out there ideas in cosmology. 28 Oct 2026
- Everyone seems to be having a collective amnesia. AI came for natural language first. Math has been much harder to crack. 27 Oct 2026
- Clever, clever coconut octopus 15 Oct 2026
- Scientific Controversies: Octopus Umwelt. Join us in the ether via livestream, available as a courtesy to paid subscribers to Higher Dimensions. Link in the comments below. 11 Oct 2026
- Scientific Controversies: Octopus Umwelt 2 Oct 2026 Scientific Controversies: Octopus Environment
- My episode with topologist Maggie Miller...and the fourth dimension that eludes mathematicians... 1 Oct 2026
- How fun. The podcast I co-host with the great @stevenstrogatz -- The Joy Of Why from @QuantaMagazine -- is nominated for a signal award. Cast your vote. Voting = loving 1 Oct 2026 vote.signalaward.com
- Join us on the pier in front of Pioneer Works, alongside the historic Mary A. Whalen, for an evening of lunar and celestial observations. The Moon will be entering the first-quarter phase and well posed for viewing from our hamlet by the sea. 19 Sept 2026 pioneerworks.org
- "It had been like dying, that sliding down the mountain pass. It had been like the death of someone, irrational, that sliding down the mountain pass and into the region of dread." -- Annie Dillard 16 Sept 2026 pioneerworks.org
- Thinking of the singular Annie Dillard in the wake of her passing. From her iconic eclipse essay: "This was the universe about which we have read so much and never before felt: the universe as a clockwork of loose spheres flung at stupefying, unauthorized speeds." -- Annie Dillard 16 Sept 2026
- If we can ask AI to write us a novel in the style of Don Quixote but in space with a canine protagonist, will we lose all of our common texts and the intellectual connection a shared text provides. 14 Sept 2026
- With the recent kerfuffle over AI solutions to a Millennium Prize Problem -- did the agents scour the unpublished chats of a human mathematician with their AI to beat him to the result? -- our recent conversation with these influential mathematicians feels so relevant and timely 14 Sept 2026
- Re-reading this excellent piece on Event Horizon Telescope this morning from @overbye in preparation for a conversation I'm having with Shep Doeleman for @QuantaMagazine and The Joy of Why. Written before EHT's success, the article really captures a beautiful moment on a mountain top in the snow beneath a massive frozen radio telescope. 13 Sept 2026 nytimes.com
- Rogue exoplanets, the dark sector, badly behaved black holes...with the capacity of a 100 Hubbles, what will NASA's Roman Space Telescope discover? Tomorrow's launch on a Falcom Heavy Rocket is a GO! 29 Aug 2026
- Tonight’s lunar eclipse is the pair to the total solar eclipse of a half-month ago 27 Aug 2026
Link verified 23 Sept 2026. Recent items update automatically from the channel.
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