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.
Comments
This is not a presentation format that inspires confidence that this is not crackpottery
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.
He also has made real contributions to magnetohydrodynamics, apparently. Talk about a mixed bag.
Being right about one thing doesn't make you right about everything, eh?
(critique of the individual cited, not you)
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].
[1] https://www.wired.com/2014/07/fantastically-wrong-hollow-ear...
[2] https://wireofinformation.wordpress.com/tag/einstein-forewor...
Edit: the opposite being, "Being wrong about one thing doesn't make you wrong about everything"
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.
"being right about one thing makes you right about everything"
and
"being wrong about one thing makes you wrong about everything."
are logically equivalent :)
Speaking only for myself, I am vastly more interested in seeing commentary on the content, than on its formatting.
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:
The theory states that the two surfaces are not disjoint:
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:
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.
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.
> Why is this going to the public before being accepted by scientists?
The usual reason for someone doing that is that they know their model won't be accepted by scientists. That's what I'm betting on here.
He has been publishing elements to this theory for the last 40 years.
See the bottom of this page: http://www.januscosmologicalmodel.com/.
Some of his latest papers have been published in Astrophysics and Space Science, Modern Physics Letters A & Progress in Physics [1]
[1] https://scholar.google.fr/scholar?hl=fr&as_sdt=0%2C5&q=JP+Pe...
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.
[1] https://arxiv.org/pdf/0807.2838.pdf [2] https://news.ycombinator.com/item?id=18609375 [3] https://cerncourier.com/does-antimatter-fall-up/
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.
Yeah, that's good, thank you.
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.
[1] https://www.mesopinions.com/petition/sante/droit-debat-nouve...
[2] https://arxiv.org/pdf/0807.2838.pdf
[3] https://en.wikipedia.org/wiki/Planetary_objects_proposed_in_...
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.