Daryl Janzen

cosmicave.orgWhat General Relativity Has Been Trying to Tell UsTwo 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 …

31 Mar

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.orgIs Time Really a Stubbornly Persistent Illusion?Einstein showed that two observers moving past each other disagree about which distant events happen at the same time, and many have concluded that there is no real “now”. But the light left over f…

Spoiler: No, it’s not. 🧪 ⚛️ ☄️ 🔭 🎢 cosmicave.org/2026/10/21/r...

cosmicave.orgWhy 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…

17 Sept

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.

Daryl Janzen@darylj.bsky.social

Here’s a sort of intellectual autobiography I wrote. I hope you find it interesting and thought-provoking. 🔭🎢☄️⚛️🧮🧪 cosmicave.org/2026/09/15/w...

15 Sept

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.orgThe Universe: from an antimatter black holeA 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…

12 Sept

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...

28 May

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...

Daryl Janzen@darylj.bsky.social

cosmicave.orgWhen black holes happenWhen 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…

28 May

Since then I’ve written two highly accessible explainers. Here’s the first one: cosmicave.org/2026/04/14/w...

cosmicave.orgChapter X: in which the inquisitive astronaut reveals the metric singularityA geometric proof that black holes remain finite in size/density, and the event horizon occurs as the next moment after the universe.

28 May

And here is the second. This should be accessible to someone with a middle school grasp of mathematics. It’s very clear. cosmicave.org/2026/05/11/x/

12 May

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.

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/

An updated figure for this thought experiment. 🧮 ⚛️ ☄️ 🎢 🧪 The thick blue line is the flash of light shone towards the black hole from Earth. The thick red lines are photons reflected back at beam splitters. The collapsing star's surface, flash of light and astronaut all arrive coincidentally at r_h.

docs.google.comWhat, exactly, is a black hole?Headline: What, exactly, is a black hole? Black holes are the most enigmatic, intriguing, captivating, confusing and confounding objects in all of physics. In fact, despite decades of focused researc...

20 Apr

@gregegansf.bsky.social @johncarlosbaez.bsky.social this is the scenario I was talking about yesterday. I ended up writing this today. Cool, isn’t it? Thats an incredibly important feature of the geometry to have just missed all this time! And so simple and profound. docs.google.com/document/d/1...

It's a fact, forced by the causal structure of the geometry. The very causal structure that defines what the event horizon is. It's a geometric identity. And it is formally proven in the paper I linked above.

…a million years before the astronaut decided to dive in. And yet the astronaut, the light ray, and the collapsing star all reach the horizon with zero metrical separation between them. They’re all coincident events. Read the formal proof here: cosmicave.org/wp-content/u... 5/5

@gregegansf.bsky.social @johncarlosbaez.bsky.social this right here might be the most incredible variant of the null temporal degeneracy theorem. Catching up with a ray of photons emitted a million years earlier while travelling < c throughout 🤯

That gap becomes identically zero by the time the astronaut reaches the horizon. At the horizon, the photons reflected back out when the ingoing null ray hit the horizon travels a radial distance dr=0 to reach the astronaut. In other words: the astronaut reaches the same light ray they earlier…3/

…shone IN to the black hole, travelling at the speed of light. The astronaut just catches up to that light ray, all while travelling there slower than the speed of light. And the surface of the star too. The star might’ve collapsed a billion years ago. The light ray might’ve been shone in…4/

As the astronaut approaches the horizon radius, the radius at which the beam splitter reflected those observed photons back gets closer and closer in r. The gap between the infalling astronaut and the place where the observed photons were reflected back shrinks the whole way down. 2/

18 Apr

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. 🧮 🧪 ⚛️ ☄️ 🎢

Daryl Janzen@darylj.bsky.social

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/

Here’s a link to the first paper for convenience. Second one below. cosmicave.org/wp-content/u...

cosmicave.org/wp-content/u...

18 Apr

Daryl Janzen@darylj.bsky.social

18 Apr

It goes without saying obviously that no one has said the opposite, that there’s an issue with the proof. But that would be weird since there isn’t, and the whole thing uses very standard tools, so anyone with a GR background could follow it. It is a beautiful proof. But the tools used are standard.

Daryl Janzen reposted

Replying to @zygolatryfoe.bsky.social

Daryl Janzen reposted

Replying to @zygolatryfoe.bsky.social

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

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.”

Daryl Janzen@darylj.bsky.social

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...

Like I’ve even written out a different sort of logical proof. A conceptual one I tried to make as accessible as possible if you want to understand how the full proof works. cosmicave.org/2026/04/14/w...

So even to say publicly “holy shit! I get this. It makes complete sense to me.” And then share it around and tell people they should really read this because it affects a lot of physics. I feel like that’s something people would want to be the first ones to do that.

The implication: there can be no point masses, no singularities in our universe. No trapped surfaces, no Hawking radiation, no information paradox. And the simple proof is verifiable by anyone with a grad-level GR background. 🧮 ⚛️ ☄️

16 Apr

@bschutz.bsky.social @hossenfelder.bsky.social @kajunut.bsky.social @nafshordi.bsky.social Or anyone else really could easily verify the null-degeneracy theorem proof and its consequences. It’s all standard physics, even if the conclusions are unexpected.

15 Apr

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...