On the first glance, this is a modestly interesting bimetric theory of gravity, one of the many. These theories are usually considered valid science, not without issues, but at least offering some new insights. See https://en.wikipedia.org/wiki/Bimetric_gravity.
On the other hand, this particular theory comes from this person: https://en.wikipedia.org/wiki/Jean-Pierre_Petit. Even if it would have been a blinding light of scientific truth (and it isn’t), he would have a hard time convincing other scientists in its validity, because of his... other convictions.
He seems to be somewhere on the schizophrenia spectrum, or at least susceptible to conspiracy theories.
But he presents his theories in a logically consistant way, or lets say at least in a way that it can be checked whether it is logically consistant. He also has many peer-reviewed publications in cosmology. The Janus stuff is properly published [1].
I don't think one easily dismiss his theory because of his other stuff.
[1] Petit, J.-P. (April 1995). "Twin universes cosmology". Astrophysics and Space Science 227 (2): 273–307.
Certainly plenty of prominent scientists have had extremely odd views, and this does not much change the validity of their work. It appears his work has been peer reviewed, although how often and by whom would be an excellent question.
The most troubling assertion is that of plagiarism. If he has really plagiarized Sabine Hossfelder, he is both foolish (plagiarizing someone so prominent would be noticed) and dishonest (which might suggest a more pervasive intellectual dishonesty).
The difficulty of course is that valid equations might be independently derived. I am curious to read why the accusations were made. I assume if they are credible that independent derivation is considered unlikely for some reason.
Incidentally, the UMMO cult is an interesting one. They're one of the more believable of the New Age-esque UFO channeling cults that sprang up in the aftermath of various New Thought (think Christian Scientists or Unity Church) and Seventh Day Adventist movements.
It's highly likely that UMMO originated as a fraud perpetrated principally by a Spanish psychologist, although there is strong evidence for other help and some evidence for the involvement of intelligence agencies, although with what motives it is difficult to say. Intelligence agencies frequently infiltrate or utilize such groups (see Richard Doty), but as there are a number of possible motivations it is impossible to suss out why in most cases.
UMMO is one of two UFO religions I'm aware of-- the other being Urantia-- where reasonably technical and somewhat correct scientific information is given at length by a channeled source. Both religions of course claim prophetic success, such as Urantia's claims about the star system Wolf 424.
They are somewhat unique in this respect, as while many other UFO religions utilize scientific concepts or language, it is not usually anywhere close to correct (or even comprehensible, sometimes).
The relevance here is that both religions have, in part because of this, and in part because they were promulgated within professional communities, attracted a disproportionate number of technically minded converts: computer scientists, engineers, physicists, and such. (Although notably few that directly study the field of the claims. A physicist, for example, is not necessarily more informed about Would 424 than other physical science professionals, and is not equivalent to an astronomer or astrophysicist, despite some overlap.)
He's also translating his youtube videos in english.
Here's a playlist of videos about his model that have been dubbed by humans [1] if you ever want to dig deeper.
If you're more interested in what he has to say about Hossfelder (and I think he's the only source on this story) you can watch the last ten minutes of his latest video [2]. Funny comics included.
Reading his wikipedia I at first assumed that he was just another crank claiming to have some grand theory of everything, but most of his ideas/theories actually seem surprisingly reasonable really. Clearly an interesting guy with a lot of wide ranging thoughts
I did not follow the development of the Janus model, but I've been a long-time reader of his blog and YouTube channel. I love the way he speaks, like a grandfather delivering anecdotes upon anecdotes in a bottomless drift of drawers opening into drawers. This guy has lived life fully. (Jewish?) orphan from WW2, he's been a street artist, a safari guide, a treasure hunter, has performed experiments that ought not to work according to his professors but did, lead published research in MHD in his garage with around 20k€ in charity fundings in the early 2000s. When he was a student and did not had hot water from the tap, he would let it heat in pipes laid under the sun or mess with his neighbors TV by blasting it with microwaves, stopping only when the pater familias would hit the TV, making the fool think he had found the subtle and right way to do it to make it work again !
He definitively has a hacker mindset and is very talented in presenting ideas from physics to a broad audience, in an accessible, out-of-the garage demystifying attitude. He has published and translated many comics about physics, in a series named the Adventures of Archibald Higgins [1], and has always been more or less of a public figure here in France, appearing on multiple TV shows these past decades.
However he's not a crank the same way the American culture presupposes it: with a clearly polarized audience and lot of money to make, individuals pursuing "personnal research", vaguely defined new age concepts like "psychic energy". There is no public figures in France like Alex Jones or David Icke. As I was looking up the name of the latter, wikipedia presents it as a "professional complotist". Well there is nobody in this category in France. Petit got interested into the UFO phenomenon in the late 60s because he saw it as a practical application of the hypersonic fluid dynamics he was working on (MHD), was set aside and forced into a "theoretical physics" closet. He did not earn much getting involved with UFOs, quite to the contrary he lost his career/fundings as an experimentalist and his reputation as a scientist.
Yet he has found a way to overcome an instability in the 60s that was thought to be a dead-end for MHD research and will go at a symposium on the subject in Russia this summer.
So he's respectable in some way but definitively says things worthy of a crank. He claims he was abducted multiple times by the same guys that gave him the idea for his model, humanoid aliens from a planet called UMMO. Now what's amazing is that he doesn't talk about it that much. You can indulge the 36 hours worth of videos about Janus you can find on YouTube (I didn't) and hear very little about alien science. He isn't obsessed with extraterrestrial visitors he's obsessed with Schwarzschild's black hole equation from 1916 and the fact the object at the center of M87 is not one but a superdense object instead.
This is pretty astonishing considering he was taken a sperm sample during one of these abductions. Here's what he has to say on the subject [2].
"The best solution ? It's not to conclude. Nowadays some people have created a kind of meta-culture around abductions, they get together, they cantillate, they analyze ... but doing this, they do not question themselves nor what is happening on Earth. The Spanish [who received letters from aliens and got involved in the UMMO case]" thought of themselves as the chosen ones. One of them told me "we have a lot of importance to them since they have invested so much time with us". She was doing a mistake here, because at one point they decided to dump everybody. They dumped the group from Madrid and they dumped Farriols. One day he received a letter saying "We would like you to restore your network and if you agree with this we invite you to call each person in the group so that we can record their emotional response". Farriols aggreed and called everybody "Would you like to join again – Yes why not !". And then nothing. Until his death. Nothing. Absolute frustration. Here is a man who devoted his whole life into that case, who cas confident, docile, collaborative. Three or 4 years laters, as he was visiting me in Aix-en-Provence he said "Son hijos de putas"."
A pretty down-to-earth attitude by my standards. But still a crank ;-). A sort of mix between Carl Sagan and Terrence McKenna.
Perhaps I don’t. Science is objective, it is not a consensus of opinions. I sincerely apologize for the criticism here, it wasn’t a good thing to do. I wish I could delete these comments, but I can’t. I can say sorry. though.
Yeah, nah. I'm not going to read something titled "Proof Donald Trump is Actually the Best President" if the link goes to "DonaldTrump.com"
First-party punditry of scientific claims is a red flag the size of Alaska. If it has the slightest whiff of merit there ought to be a neutral third-party expert willing to bang out an article about it.
Unfortunately I cannot find the video/article where he states he's marketing this theory via a website because it's met with indifference, like any other theory: it takes times – years, sometimes decades – for a theory to be heard, let alone be opposed.
I find this page very annoying. Instead of presenting the core of the theory (maybe some maths?), it has happy pictures and fell good text. But even after reading the Wikipedia article, I'm no wiser.
It takes years for an idea to gain momentum in the scientific community. It does not take years to get an article on a half-creditable site like Ars Technica or Space.com. Marketing an idea directly to the public, i.e., people who can't do math, is suspicious as hell.
The author has published papers on his model in various peer-reviewed journals. Check out the bottom of the home page. As I said, he theorized, went through the peer-review ping pong session, published and then set up this website, which is why I compare him to Deutsch, who went through the same steps.
Dr. Petit has said that his theories are based on his personal interactions with aliens and that the U.S. Army has tested antimatter bombs on Jupiter, so there's that.
The opposite is just true as well. For instance Halley supported the Hollow Earth Theory [1]. And Einstein wrote a foreword to a book detailing how the Earth crust would slide in one dramatic cataclysm [2].
To some extent, you have to be a crank to have the confidence and persistence in opposing the vast majority of established thought long enough to discover something new. "The distance between genius and insanity is measured only by success."
Of course, that doesn't mean that the rest of us are obligated to listen to any of it until that success has been realized.
Interesting comment, seeing as most of the other comments to this post takes the opposite position; they're implying being wrong about one thing makes one wrong about everything.
Yes, being right about one thing doesn't make you right about everything, but being wrong about one thing makes you wrong about everything. It is known. (Especially when aliens are involved.)
It's a fundamental breaking of symmetry in our universe, also known as: luck is blind, but curse has 10/10 eyesight.
Just skimming, I find two obvious issues with the proposed model:
First, saying that spacetime, considered as a 4-d hypersurface, has "two sides with two metrics" won't work. The metric of one side fully determines the metric of the other side since both sides belong to the same surface. That's why spacetime in standard Einstein GR only has one metric (which, btw, does not mean that spacetime in standard GR has only one "side", as the article claims). Two different metrics would have to describe two different, disjoint surfaces, which would have no connection to each other, which would mean the second one, being unobservable, would be scraped right off the model by Occam's razor.
Second, saying that negative mass would induce "opposite curvatures" as compared to positive mass, in the same spacetime, won't work. One spacetime can only have one curvature at any given ponit. Considering the simpler example of a 2-d surface should make this intuitively obvious--the same surface can't have two different curvatures at the same point.
Also just skimming, and furthermore not a physicist, but I'm not sure your critique works:
> Two different metrics would have to describe two different, disjoint surfaces, which would have no connection to each other, which would mean the second one, being unobservable, would be scraped right off the model by Occam's razor.
The theory states that the two surfaces are not disjoint:
> What is important to note however, is that the two field equations are coupled, i.e. a mass always creates a positive curvature in spacetime according to its own metric (where the mass appears visible), and it also always induces a negative curvature in the conjugate metric (where the mass appears invisible).
I do find it confusing why this would be called two metrics, however, since it seems to be describing a unified spacetime "surface".
As for your second critique:
> One spacetime can only have one curvature at any given ponit. Considering the simpler example of a 2-d surface should make this intuitively obvious--the same surface can't have two different curvatures at the same point.
But if the surface has two sides, can it not? Consider the classic "gravity well" demonstration of a heavy ball placed on an elastic membrane. It forms a concave surface. Now turn your head upside down and look at the membrane from underneath. You'll see a convex surface. Same membrane, different curvatures.
Anyhow, I'm certainly not equipped to analyse this theory, but I do like that it attempts to make falsifiable predictions. I guess it's an attempt to explain dark energy? It would appear to leave problems of dark matter unaddressed, however.
> But if the surface has two sides, can it not? Consider the classic "gravity well" demonstration of a heavy ball placed on an elastic membrane. It forms a concave surface. Now turn your head upside down and look at the membrane from underneath. You'll see a convex surface. Same membrane, different curvatures.
You're thinking of this as someone who can look at the surface from the outside, in which case it makes sense to consider convex and concave curvatures to be different. But if you're restricted to moving within the surface, there's no way to tell the difference.
Within the surface, you can only measure the distances traveled along certain paths. For these distances, it doesn't matter whether you're walking across a hill or a valley of the opposite shape. The metrics of these surfaces are exactly the same.
That doesn't mean that negative curvature is impossible, just that it isn't as simple as inverting convex and concave. A negatively curved two-dimensional surface curves simultaneously in opposite directions, like a saddle point. But there's no way to have two surfaces with inverted curvatures at corresponding points, since curvature is determined by the arrangement of points, which means that inverting curvature obliterates the whole concept of "corresponding points" by arranging them differently.
> The theory states that the two surfaces are not disjoint
Yes, but that just underscores my point that one surface can only have one metric.
> But if the surface has two sides, can it not?
No. You can describe the one curvature in two different ways, depending on which side you choose as your viewpoint. But it's still just one surface and one curvature, not two.
Why is this going to the public before being accepted by scientists? This format is appropriate for things that have been known to be true for twenty years, not random models. Taking your ideas straight to the public before obtaining wide expert agreement is actually one of the signs of physics-themed crackpottery.
We may be talking past one another here with the word "format". I read and responded to what seemed yet another round of irrelevant (or at least low-signal), "This site looks terrible on mobile" style noise, which HN discussions are sometimes entirely too full of. Now, however, I think you (and possibly the grandparent comment) may have been talking about addressing the content to a general audience, instead of peer review.
If that's the case, I apologize for my own noise.
EDIT: Even so, that The Fine Article is (potentially) directed at an inappropriate audience doesn't tell me much about its "crackpottery", except in a mildly Bayesian kind of way.
I like to pay attention to the discussions on physics articles that cross the HN front page because I more often than not learn something by reading the conversations between the people who understand the material better than I do. That remains the kind of discussion I want to see.
Watch out - he's publishing a model, not facts. In physics you are allowed to publish "random models," so to speak, on nothing other than the hope that at some point in the future someome will identify them as true or false.
There's a huge difference between a paper about a model being published, and the model being accepted as a true fact.
Agreed. Now what's more interesting is that his model is close enough to the one developed in a paper from 2008 by Sabine Hossenfelder [1]. Close enough to be accused of plagiarism when he reached out to her. We discussed this article 5 months ago: "'Dark fluid' with negative mass could dominate the universe" [2]. Experiments are currently being setup to see how antimatter behaves in a free-fall situation [3]. The lead scientist says it will fall up, while Petit asserts it will fall down.
So it's not like this model is totally isolated from what is being done in physics, although he has developed it on his own. He's into bimetric models of gravity like many other people in his field, and as far as I can tell, this is Occam's bush growing we are seeing here. Let's not hasten to use the razzor.
I'd say that a discussion and criticism by experts must be required, not really wide acceptance. In theoretical physics, there can be many competing models that could be hard to verify or proof wrong. "Science advances one funeral at a time", progress is made quite slowly to make everyone accept a new theory.
Edit: So, I'd like to see a peer-reviewed article by the author, and some responses by people in the field. That could be enough for a new theory.
If you look at the bottom of every page, including the homepage, the author references his own relevant peer-reviewed articles.
I'm not saying his theory is right, or that the presentation doesn't smell a bit of crackpottery (it does), but at least he's referencing some real science he's done and that has apparently been accepted.
This is the main point he's upset about. Because of his interest in the UFO phenomenon in the 70s and 80s he has been ostracized from the wider french community (mostly the state-run National Center of Scientific Research aka the CNRS). It's not a subject he wants to talk about anymore.
His main grief is not that his genius theory is not understood , but that he cannot discuss it with his colleagues for the reason above.
People have set up a petition [1] so that he present his ideas during a seminary (he's indeed quite popular with videos on youtube frequently reaching more than 100k views).
To give you a more concrete example, he stumbled upon a paper by physicist Sabine Hossenfelder [2] which presents a very similar approach to the Janus model but with a broader, more abstract framework Petit is not able to understand. He reached out to her and was accused of plagiarism ! He tried to play it cool, saying she would be remembered as the 21st century's Einstein (her paper predates his by a decade), telling her she should invest energy into this (she published that paper in 2008 and did not follow this track further) offering her to collaborate as friends on the subject. Result: she declined because of his background.
Now, what background are we talking about ? IIRC he published a paper in the 90s where he thanked M. Bazoof. What you have to know is that Petit has been personally involved in the UMMO affaire [3]. Along with several people, mostly from Spain, he received letters and phone calls by people that claimed to be from another planet. These letters were full of scientific content and he's written multiple books about it (the latest, from last year, is jokingly subtilted "How far can we think to far ?"). Back to M Bazoof: "What ? He is citing an alien ? Is he kidding us ?" => that's Petit that imitates his colleagues' reaction back in the days, and then he burst in laughter. Serious again: "But that's the truth, alien or trickster, I received UMMO messages without which I would not have thought of the Janus model. A stuff life this, this is is insane, you have no idea. It brings you into a life-long adventure. It's like my life is the script to a Spielberg movie. And I suppose I'm Doc from back to the future ! laughs".
"If it's not fun, it's not really serious" is one of the maxims he lives by.
Ad hominem attacks instead of real arguments about the proposed theory is mean and not professional.. If that's what happened. My guess is that many areas of theoretical physics are getting too competitive, while funding is always limited. So, intellectual merit could be not the only (or not the main) consideration, outwheighed by things like reputation. Most mainstream researchers also have their own pet theories, and defending "some UFO guy's theory" that might compete with their own pet theory is hardly a priority for them either, especially at such a reputation cost. In the field that has so many theories that are hard to prove right or wrong, human capital and connections could decide the future of your theory, apparently.
Sabine Hossenfelder is an open-minded researcher, as far as I can tell. Sad that the author could not follow up with her, but there must be reasons for that.
Very interesting, thank you for the comment. I like math and computer science academia more than physics for these reasons -- people are less cut-throat, and generally more fun than in physics.
He managed to publish this theory in some peer-reviewed venues, so there’s that. However, it is a minor hypothesis on the verge of fringe science (but not quite there), not some blinding glimpse of genius.
A little OT, but there was a XKCD-comic about a 'space-layer' made of a 'polygone-structure' - and I for for the abstract first thought, 'Randall better had written about a (for the 2D-shema) five-sided-(pentagon)-layer', cos if you think -just for a moment - about measuring and data-gathering-structures for mapping space maybe... - after you measured the size, temp, coordinates, and maybe 'relations' (for an example: possibility for water -in a survival-scenario... it was about astronomy) - I realized, the pentagon-figure 'shrinks' in a triangle, but 'You better have one more data-point open -for maybe future purposes'
Now I feel a bit fuzzie cos just 5 Minutes ago there was a posting here on HN someone saying something like: 'Somebody made an UI and for years it became the main theme... ' (-;
On the first glance, this is a modestly interesting bimetric theory of gravity, one of the many. These theories are usually considered valid science, not without issues, but at least offering some new insights. See https://en.wikipedia.org/wiki/Bimetric_gravity.
On the other hand, this particular theory comes from this person: https://en.wikipedia.org/wiki/Jean-Pierre_Petit. Even if it would have been a blinding light of scientific truth (and it isn’t), he would have a hard time convincing other scientists in its validity, because of his... other convictions.