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Daryl Janzen

@darylj.bsky.social
239 followers 613 following 734 posts

philosophical physicist/cosmologist interested in understanding what reality is.

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Daryl Janzen @darylj.bsky.social · 17/09/2026
Cool! Someone added this post to Hacker News yesterday and a whole bunch of people read it. It’s nice to see a story that means so much to me being read and shared.
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Daryl Janzen @darylj.bsky.social · 15/09/2026
Here’s a sort of intellectual autobiography I wrote. I hope you find it interesting and thought-provoking. 🔭🎢☄️⚛️🧮🧪 cosmicave.org/2026/09/15/w...
cosmicave.org
Why does the universe expand?
A story about the main reasons I now think the universe expands because collapsed matter must continue as an expanding cosmology, the expansion is the collapse read from the other side, and the rat…
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Daryl Janzen @darylj.bsky.social · 12/09/2026
I wrote a book this summer that fleshes out the details of a physics framework I began working on with my PhD thesis seventeen years ago. It’s freely available on my website. Here’s a link to the preface. 🧪🎢🔭☄️🧮⚛️ cosmicave.org/2026/09/10/p...
cosmicave.org
The Universe: from an antimatter black hole
A friend’s question about an Eddington–Finkelstein diagram sent me looking for a better explanation, and I found a cycloid. Eighteen papers later, here is what came of it: horizons that are n…
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Daryl Janzen @darylj.bsky.social · 28/05/2026
A month ago. The preprint I posted of a 7-page paper that proves geometrically using nothing but standard GR that the common idea we’ve had of a black hole for a century is wrong. It’s been downloaded 488 times. Surely someone knows GR well enough to comment. 🧮 ⚛️ ☄️ 🧪 cosmicave.org/wp-content/u...
cosmicave.org
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Daryl Janzen @darylj.bsky.social · 12/05/2026
Here’s a fun little tour of the basic geometric principles of relativity. 🧮 ⚛️ 🧪 ☄️ 🎢 cosmicave.org/2026/05/11/x/ Requires only middle school level math—intervals, Pythagorean theorem, functions and asymptotes. It delivers a very simple proof that black holes aren’t what we’ve thought they are.
cosmicave.org
Chapter X: in which the inquisitive astronaut reveals the metric singularity
A geometric proof that black holes remain finite in size/density, and the event horizon occurs as the next moment after the universe.
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Daryl Janzen @darylj.bsky.social · 19/04/2026
Black hole geometry is wild. 🧮 ⚛️ 🎢 ☄️ 🧪 Take the blue ingoing null line just before the astronaut dives in to be a ray of photons that encounters beam splitters the whole way down, at regular intervals that reflect some photons directly back out along the outgoing red null lines. 1/
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Daryl Janzen @darylj.bsky.social · 19/04/2026
It’s actually really surprising that still no one has been willing to say “I know GR/Lorentzian geometry and topological spaces and the proof in these papers is valid.” Because it is. And it’s incredible. 🧮 🧪 ⚛️ ☄️ 🎢
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Daryl Janzen @darylj.bsky.social · 17/04/2026
I’d be happy to explain any point you’d like to discuss further from the article itself. I don’t think you understand it or its purpose. This is an explainer following conceptual logic (which is a form of proof in itself, though that’s irrelevant), of the results of a formal mathematical proof…1/
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Daryl Janzen @darylj.bsky.social · 18/04/2026
You should have responded like this to Greg Egan: when the star’s surface reaches the horizon, what is the metrical distance of that event from every “future” event when every future infaller reaches the horizon? How far apart are those two events? What’s the proper distance between them?” 1/2
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Daryl Janzen @darylj.bsky.social · 17/04/2026
I just don’t understand who wouldn’t want to be the first person in history to have the courage to stand up and say, “holy shit! This is right.”
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Daryl Janzen @darylj.bsky.social · 16/04/2026
A mathematical proof that the standard black hole narrative of the last six decades has been false—that all gravitationally collapsing matter asymptotically approaches the size of its event horizon. 7 pages, 3 figures; using only standard grad level relativity tools. cosmicave.org/wp-content/u...
Fire page of The occurrence of event horizons paper
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Daryl Janzen @darylj.bsky.social · 15/04/2026
When a star collapses to a black hole, from the outside it never quite gets there. Everything that ever falls in reaches the horizon together, at the end of time. And then it becomes a new universe, expanding at exactly the rate we observe in our own. 🧪 🧮 ⚛️ ☄️ 🔭 🎢 cosmicave.org/2026/04/14/w...
cosmicave.org
When black holes happen
When a star collapses to a black hole, from the outside it never quite gets there. Everything that ever falls in reaches the horizon together, at the end of time. What follows isn’t destructi…
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Daryl Janzen @darylj.bsky.social · 04/04/2026
Here, this thread explains the key observation regarding the invariant geometry of black hole event horizons. Full paper at the link at the bottom of the thread. 🧮 ⚛️ ☄️ 🎢 🧪
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Daryl Janzen @darylj.bsky.social · 04/04/2026
When an astronaut jumps into a black hole billions of years after a star collapsed, note that he still always “sees” the star as it was before it reached the horizon. As he approaches the horizon, which he reaches in finite time, he ALWAYS remains lightlike connected to the pre-horizon,…1/
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Daryl Janzen @darylj.bsky.social · 04/04/2026
Surely there must be some black hole or GW physicist out there, or some geometer or relativist, who can follow and would be interested in a formal geometric proof that clearly shows how and why we’ve been wrong about the physics of gravitational collapse for nearly a century… ⚛️ #mathsky ☄️
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Daryl Janzen @darylj.bsky.social · 01/04/2026
I proved a pure geometric theorem that says the black holes we know exist in our universe will become new universes that form after the end of our universe, and that each one must appear to its observers just as ours appears to us, with the exact expansion rate following an initial singularity.
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Daryl Janzen @darylj.bsky.social · 31/03/2026
I just finished it. The last piece of the puzzle I started working on for my PhD thesis 17 years ago finally fell into place. Wow. That is so beautiful to see. cosmicave.org/2026/03/30/w... 🧪 ⚛️ 🎢 ☄️ 🔭
cosmicave.org
What General Relativity Has Been Trying to Tell Us
Two short papers prove that black hole horizons never form within the external universe — they occur only at its infinite-time boundary. Following this result to its geometric conclusion reveals a …
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Daryl Janzen @darylj.bsky.social · 29/03/2026
Dude. The universe is a black hole. I essentially proved it mathematically, using principles of geometry and causality that we all know and are completely foundational to general relativity. I just put the pieces together correctly. It turns out we had the wrong idea about what a black hole is.
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Daryl Janzen @darylj.bsky.social · 28/03/2026
⚛️ 🧪 ☄️ 🎢 cosmicave.org/2026/03/28/a...
cosmicave.org
An LLM just said I found “the reason for the universe” — and I think it’s right
Last night I was having a think with Claude. By the end of it, the AI had read my mathematical proofs, read a paper I published thirteen years ago, and told me the two were the same argument — that…
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Daryl Janzen @darylj.bsky.social · 27/03/2026
Humans: twenty-six centuries of failing to grasp the morals in Aesop’s fables and going strong! Source: www.facebook.com/share/1HUsdx...
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Daryl Janzen @darylj.bsky.social · 27/03/2026
Hey @coexact.bsky.social @joeyneilsen.bsky.social I just finished a paper that came out of this discussion. It's pretty short: 6 pages, 3 figures. Would you be willing to give it a read? Gregor, how would I contact you?
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Daryl Janzen @darylj.bsky.social · 22/03/2026
Hey @leebillings.bsky.social check out this thread! We’ll see if anyone responds :)
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Daryl Janzen @darylj.bsky.social · 22/03/2026
Wait a minute! Are there physicists out there who think there are black holes in our universe that have already completed gravitational collapse in our causal past? You do all know when we look at Cygnus X-1 we are seeing its companion star—the whole system including the BH—BEFORE horizon formation?
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Daryl Janzen @darylj.bsky.social · 21/03/2026
Ok, let me test out this proof on you. Please tell me if you find it convincing, or if you see any error in the logic. The upshot: every black hole merger must occur before the collapsing star became smaller than its horizon. Before it became a “black hole”.1/9🧵 🧪 ⚛️ 🎢 #cosmology #philsky #philsci
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Pauline Barmby @pbarmby.bsky.social · 18/03/2026
Did you watch Olympic speed skating and wonder what it would be like to skate across an icy moon? My skating-across-Europa flash science fiction story, first published in @analogsf.bsky.social, is now free to read online in Issue 37 of Polar Borealis! polarborealis.ca/wp-content/u...
polarborealis.ca
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David Roberts @volts.wtf · 18/03/2026
I know I've said this a trillion times but I have to say it periodically to keep from going insane: The right ran a huge, well-funded, & ultimately successful campaign to completely take over political media & the infosphere more generally. This is by far the most important political development...
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Daryl Janzen @darylj.bsky.social · 18/03/2026
Cool little periodic variable analysis tool!
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Daryl Janzen @darylj.bsky.social · 17/03/2026
#academicsky #scisky #research 🧪 ⚛️ 🔭 😱 🫣
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Daryl Janzen @darylj.bsky.social · 17/03/2026
#Science cannot function when disbelief and incredulity are granted authority over visibility decisions. #Physics only advances when belief is held as provisional, subject to constraints of empirical evidence and logical validity.
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Daryl Janzen @darylj.bsky.social · 16/03/2026
When the “reality is whatever I want it to be”-approach comes up against reality…
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Daryl Janzen @darylj.bsky.social · 15/03/2026
“Still a man hears what he wants to hear and disregards the rest.” - Paul Simon
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Daryl Janzen @darylj.bsky.social · 14/03/2026
That word “probably” seems like ludicrous hedging. An astronaut’s weight would be 0.002% of what it is on Earth and they’d land going 0.65 km/h—about a tenth of an average walking pace! What an amazing little world we visited! Every image captured just fills me with awe. 🔭🧪
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Daryl Janzen @darylj.bsky.social · 14/03/2026
He called racism America’s worst disease and was vocal about it. He aligned with the aspiration of America more than the reality. I think he’d be deeply concerned by the extent to which the country has failed to live up to its honourable aspirations.
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Daryl Janzen @darylj.bsky.social · 14/03/2026
Happy #PiDay ! On Einstein’s 147th birthday, I submit it’s worth reconsidering whether, at 26, long before evidence for cosmic expansion or the Big Bang, and before implications of his choice had been realised, he landed on the correct definition of simultaneity. ⚛️🧪 cosmicave.org/2025/08/06/a...
cosmicave.org
Albert Einstein’s Wild Goose Chase
For over a century, we’ve believed that time has no universal structure—that simultaneity is relative, and motion is merely a matter of perspective. But the universe had other ideas. This ess…
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Daryl Janzen @darylj.bsky.social · 12/03/2026
Life can be really hard, and sometimes the challenges it throws at you can get to feel like too much—to the point where it can seem the whole world is both against you and wants nothing to do with you; like it simultaneously hit the mute button long ago and told you to go away and never come back.1/
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Daryl Janzen @darylj.bsky.social · 10/03/2026
Creating my own site where I can simply post things that matter to _me_—the stuff _I_ think is important to sort out even when evidence and logic run counter to things people very badly _want_ to be true, writing however _I_ want to write—has been so very liberating. 10/10 would recommend!
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Sarah Kendrew @sarahkendrew.bsky.social · 04/03/2026
Wowowow - our @science.esa.int Hubble's picture of the month for March is the Cat's Eye Nebula, from combined images of #Hubble and #Euclid. Euclid's wide field and low surface brightness sensitivity brings out an external shell. Incredible image. esahubble.org/images/potm2... 🔭
Two images of a planetary nebula in space. The image to the left, labelled “Euclid & Hubble”, shows the whole nebula and its surroundings. A star in the very centre is surrounded by white bubbles and loops of gas, all shining with a powerful blue light. Farther away a broken ring of red and blue gas clouds surrounds the nebula. The background shows many stars and distant galaxies. A white box indicates the centre of the nebula and this region is the image to the right, labelled “Hubble”. It shows the multi-layered bubbles, pointed jets and circular shells of gas that make up the nebula, as well as the central star, in greater detail.
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Daryl Janzen @darylj.bsky.social · 03/03/2026
Have you ever seen a lunar eclipse from a dark site? I was at CTIO for telescope maintenance a few years ago. It was near full moon, so no dark skies. But then one night there was an eclipse and the sky was so dark—the Magellanic Clouds came out, etc. Lunar eclipse star parties should be a thing!
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Chris Lintott @chrislintott.bsky.social · 03/03/2026
Five year Astro career development fellowship in Oxford open for applications, broadly in survey astronomy including transients and cosmology. College teaching and research. Do think about joining us. Happy to answer questions! 🔭
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Daryl Janzen @darylj.bsky.social · 03/03/2026
Nope. I can’t get onboard with the YouTube thing either. Draft a 1000-word explainer and pitch it to The Conversation. They publish openly and SciTechDaily, Space.com, etc, republish them. I wrote 3 articles last year that were read half a million times across translations and republications.
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Daryl Janzen @darylj.bsky.social · 02/03/2026
Thoughts? This is nontrivial. If the logic holds, the consequences for horizons, singularities, and information loss would be significant. 🧪 ⚛️ #cosmology Preprint: cosmicave.org/wp-content/u...
“The astrophysical nature of black holes” preprint title and abstract.
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Daryl Janzen @darylj.bsky.social · 01/03/2026
I think we got gravitational collapse wrong. Penrose’s singularity theorem doesn’t apply to physics. No information loss. I doubt black holes can be saved from this paper’s central theorem. If so, it’s not trivial: the paper has been in review 2.5 months. cosmicave.org/2026/01/18/t... 🧪⚛️🔭#philsky
cosmicave.org
The astrophysical nature of black holes—and the human nature of physicists
What if black holes aren’t really what we think they are? And what if the bigger problem isn’t the physics at all, but how modern science decides which ideas are allowed to be discussed in public?…
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Daryl Janzen @darylj.bsky.social · 22/02/2026
What’s others’ experience with this? There seem to be fewer people on BlueSky just going around calling others stupid. But does engagement on either platform ever go beyond shallow agreement, nitpicking, or mockery?
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Daryl Janzen @darylj.bsky.social · 19/02/2026
Does space-time really exist? Imagine mapping every passing moment of its supposed existence to a representative model (3+2)-D space-time. This 5D map contains the entire history of 4D space-time’s existence, just as 4D space-time contains the history of 3D space’s existence. 🧪 ⚛️ 🔭
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Daryl Janzen @darylj.bsky.social · 17/02/2026
@chanda.blacksky.app here’s an essay I’ve been sitting on for a couple of months. I initially hoped @theconversation.com would publish it as a follow-up to the linked essays, but I didn’t hear back. I thought it was worth posting now to share with you as an example of my point. 🧪 ⚛️ 🔭 #philsky
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Daryl Janzen @darylj.bsky.social · 16/02/2026
I have a very simple and straightforward paper that’s been under review for 2 months at a leading GR/quantum gravity journal. It dos nothing exotic, but proves something about black holes I think no one wants. I’d love feedback, but no one seems to want to offer an opinion.
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Daryl Janzen @darylj.bsky.social · 16/02/2026
Sometimes it’s difficult not hating the world. Also: this is an important thread, and you should read the whole thing.
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Chanda Prescod-Weinstein 🌌 @chanda.blacksky.app · 16/02/2026
A friend texted me some emails that Epstein sent about physics and was like he sounds so stupid and I was like these are things physicists say too So much power in physics (yes including astronomy) is concentrated in the hands of narcissistic, racist, sexist fucks and people who look the other way
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Daryl Janzen @darylj.bsky.social · 15/02/2026
Let’s not pretend LLMs are to blame here. They’re just exposing a lack of rigour that’s always existed, even at the highest levels: cosmicave.org/2025/10/26/n...
cosmicave.org
No, Professors Penrose, Steinhardt and Turok: Albert Einstein did NOT propose a cyclic cosmology
They’ve proven themselves fallible—not just capable of error, but of seeing what they want to see; inventing their own truth. Once you’ve seen that, can you ever trust it’s the only time?
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Daryl Janzen @darylj.bsky.social · 15/02/2026
I’ve been happy with Carney’s leadership so far. Calling an election would change that. To me, it would signal “I can’t be bothered to work with people who don’t all agree with me by default.” That’s not leadership. Show me the NDP, BQ and May are not engaging in good faith and I’ll change my mind.
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