Janus cosmology: what is negative mass?

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.)

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.

[1] https://www.savoir-sans-frontieres.com/JPP/telechargeables/f...

[2] https://www.youtube.com/watch?v=iMVvSHXurmU&t=47m25s (automatic subtitles are available)

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.