HUGE blow for alternate theory of gravity MOND

MOND stands for MOdified Newtonian Dynamics. MOND proponents say Dark Matter may not exist and observations can be explained by modifying Newton's gravity at low accelerations. This has been a hot topic lately after an author named Chae published a paper saying his analysis of GAIA data supports MOND. For example, here's an article from August 2023 about that:

Smoking-gun evidence for modified gravity at low acceleration from Gaia observations of wide binary stars

A new study reports conclusive evidence for the breakdown of standard gravity in the low acceleration limit from a verifiable analysis of the orbital motions of long-period, widely separated, binary stars, usually referred to as wide binaries in astronomy and astrophysics.

The study carried out by Kyu-Hyun Chae, professor of physics and astronomy at Sejong University in Seoul, used up to 26,500 wide binaries within 650 light years (LY) observed by European Space Agency's Gaia space telescope.

We even had our own ATS RussianTroll write about this paper as if it was some kind of fact and not in error:

Einstein's theory failed. The world is entering a new reality.

Unfortunately, RussianTroll failed to consider there were already other papers on the subject which didn't agree with Chae's findings.
A new study was done by a scientist who has been a long-time supporter of MOND, and wrote a review of the evidence for MOND, Dr. Indranil Banik.

F rom galaxy bars to the Hubble tension: a comprehensive review of evidence concerning MOND, by Dr. Indranil Banik

Banik and Collaborators reviewed the Chae paper of about 26,500 wide binaries, and found the statistical methods were not good and that the quality checks for the data used were not good. After applying quality checks to the data, the data set reduces from about 26,000 to about 21,000 and the support for MOND claimed by Chae disappears. Furthermore Banik and collaborators selected an even higher quality group of data without some of the large uncertainties in Chae's data, and that analysis excludes MOND to 16 sigma (a sigma of at least 5 is often considered a convincing result in scientific circles). Here's a link to the Banik paper, which explains the problems they found with Chae's paper, and their own analysis, which supports Newton's gravity model:

Strong constraints on the gravitational law from Gaia DR3 wide binaries

an overwhelmingly strong preference for Newtonian gravity remains in a considerable range of variations to our analysis

Here's a video by astrophysicist Dr. Becky Smethurst explaining that she read Banik's 45-page paper, and finds the arguments that it has better statistical methods and better quality checks on the data convincing.

HUGE blow for alternate theory of gravity MOND

A new research study was published this month claiming to have completely ruled out an alternate theory of gravity called MOND, that doesn’t need dark matter to explain our observations of the Universe. They used the same data that four other research studies have used in the last couple of years, but used a more rigorous method, and their results now contradict the findings of those other papers. So what is going on here?

Feel free to watch the video for details, which Dr. Becky is good at explaining to laypeople in an understandable way (usually). Here are her comments about the Banik paper from time 15:09

...personally I believe the results presented by Banik collaborators over the results presented by Chae.
The method is more rigorous, the data is more reliable because of all the quality cuts, and every single question I had was answered in the 45 pages of this research paper.

It's very thorough, and it has to be. The first author of this paper is Indranil Banik, one of the biggest supporters of MOND for a long time, who literally just last year wrote the book on all the evidence for Mond. If he's now first author of a paper that rules out MOND to that level of significance it does have to have all of the detail.

So I can't understate how huge this is, if one of the biggest supporters of MOND for a long time, Dr. Banik, just authored a paper ruling out MOND to a very high confidence of 16 sigma. However the last sentence in the abstract of his paper implies he may not have given up completely on MOND in some other form, though he has apparently ruled it out in its current form.

Since MOND was the most popular alternative to dark matter, (and I know some people don't like dark matter), then to explain observations, we are left with either dark matter, or else finding some other alternative theory besides MOND. There are some, but none that I know of had the widespread support that MOND did (note the use of past tense; if Dr. Becky is convinced, I don't think she's the only one).

So, we are still left with a truly great mystery, in fact some might say one of the greatest mysteries in the universe, and who doesn't like a great mystery? What is causing stars orbiting galaxies to orbit as if there is more mass there than can be seen? If the alternate theory of gravity MOND doesn't explain it, as this recent paper by Banik et al suggests, what does? Dark matter, or something else? Searches for dark matter have so far been unsuccessful, so we are really having difficulty figuring out how to explain observations.

a reply to: Arbitrageur

Nice one, coming out swinging for the orthodoxy. Fair enough, except that there isn’t anything intrinsically more convincing about the paper you favour compared to the other. They’re both massaging the same data and ‘rigour’ is merely a matter of personal opinion until it can be demonstrated that the results are indeed accurate. Which won’t be for some few thousand years yet, I should say (the days of game-changing fundamental discoveries, like the spectroscope, are most likely over).

It really isn’t in anyone’s interest to get so excited about this. If you’re in the field that’s different, of course, but while it may be fun to reprise the quarrels of the astrophysics community on Above Top Secret, all you’re going to achieve is to encourage people to speculate about something they are totally unqualified to hold an opinion about.

For what it’s worth, I think you’re probably right about MOND, but − as J.B.S. Haldane famously pointed out − the Universe is queerer than we can imagine. It has consistently failed to live up to the predictions of science for the past six hundred years and I don’t suppose it’s going to start behaving now. I’d turn down the certainty dial a good half-dozen notches if I were you.

a reply to: Arbitrageur

Our own DNA can talk to itself on the other side of the planet.

The real nerds are going over string theory now.

But thanks for your post...

Actually, I know all I need to know about gravity. It holds me so I can walk on the earth. It can cause you to get hurt if you trip and fall or fall off the roof or ladder.

Is it really necessary to find out how it precisely works to live our life on this earth? Maybe it does to those who make money doing the research, I would rather know how to make really good puff pastry myself.

You have people arguing about the science of gravity out there....and they call us nuts for posting on a conspiracy site.

a reply to: rickymouse

Actually, I know all I need to know about gravity. It holds me so I can walk on the earth. It can cause you to get hurt if you trip and fall or fall off the roof or ladder.

However, there are people who design pumps, pendulums and parachutes, people who make and use highly accurate clocks and GPS systems, people who calculate the flight paths of spacecraft and guided missiles, and people in many other occupations and walks of life who need to know a hell of a lot more about gravity than you do.

Is it really necessary to find out how it precisely works to live our life on this earth?

Depends on what life you want to live, I suppose. I like to know how everything that affects my life works − from rock splitters to economic systems to gravity − at least in principle. Understanding the world and human nature, and how it all fits together, is the reason I don’t need conspiracy theories to make sense of my life.

Maybe it does to those who make money doing the research

Do you think anyone makes more than a decent living researching gravity? Or makes huge profits designing and manufacturing the instruments used in that research? I think you are greatly mistaken. Besides, there are any number of far easier ways to make money.

You have people arguing about the science of gravity out there....and they call us nuts for posting on a conspiracy site.

Are you saying it’s nuts to argue over theories of gravity? I agree that doing it on a site populated by poorly educated eccentrics and grudge-bearers is rather a silly thing to do, but there’s nothing insane about doing it.

originally posted by: Astyanax
I’d turn down the certainty dial a good half-dozen notches if I were you.

Certainty about what? Banik's paper doesn't even address Einstein's model, which is supposed to be the best gravity model we have so far. There is certainly lots of data confirming that model seems to be accurate so far. But even Einstein's model isn't a holy grail when it cones to the center of a black hole where it loses its ability to make useful predictions, so I don't even have any certainty about Einstein's model as being ultimate, just that it has passed lots and lots of tests.

Banik's paper compares MOND to Newton's model, and excludes MOND in favor of Newton's model. We already know Newton's model runs into problems with things like the precession of the perihelion of Mercury, so it would be silly to claim we have certainty Newton's model is correct when we know it's not in situations like that. But how certain are we that MOND is incorrect from Banik's paper? His claim is 16 sigma. I'm willing to go where the data lead me, but that doesn't appear to be in the direction of MOND at this point.

originally posted by: rickymouse
Actually, I know all I need to know about gravity. It holds me so I can walk on the earth. It can cause you to get hurt if you trip and fall or fall off the roof or ladder.

Is it really necessary to find out how it precisely works to live our life on this earth? Maybe it does to those who make money doing the research, I would rather know how to make really good puff pastry myself.

You have people arguing about the science of gravity out there....and they call us nuts for posting on a conspiracy site.

Some people like a good mystery, and I suppose some people don't care. It's not just gravity, the big mystery is that we don't know what 95% of the universe is made of. Aren't you curious about the other 95% we don't understand? If not, that's fine, but I think a lot of people are interested in that. What if some of the other 95% helps you figure out how to make a better pastry, or heat your home for less? I'm not saying it will, but we don't know what it is until we know what it is. For now we just use place holder names like "dark matter" and "dark energy". The idea of MOND was that we don't need "dark matter" to explain observations, but after this major blow to MOND, maybe we do.

a reply to: Astyanax

all you’re going to achieve is to encourage people to speculate about something they are totally unqualified to hold an opinion about.

Sounds like those qualified are still speculating as well over this one. Lot of interest in gravity, crack this one and could open up a new age in space travel. Lets say someone comes out tomorrow with the algorithm of how it all works, would it be a national security matter and subject to such action?

a reply to: Arbitrageur

We already know Newton's model runs into problems with things like the precession of the perihelion of Mercury

One thing that is dark with Mercury is exactly what is happening under the surface. Could there be something wrong with the estimates of it mass or are the internal fluid dynamics doing something unexpected being a hotter planet?

a reply to: Arbitrageur

Certainty about what?

About which of two distinguished scientists is more likely to be right in their interpretation of JWST data.

a reply to: Astyanax

About which of two distinguished scientists is more likely to be right in their interpretation of JWST data.

I am not qualified in astrophysics, I am in information. With the growing volume of information to process and the exponential curve this is on as more sensors and larger databases grow, it hurts my head thinking about it.

It is good to see these debates, different approaches and a spirit for wanting to know more going on. This is what took us out of the stone age. For now I see both these attempts as early explorers into the unknown, trying to find some solid ground and structure in how we navigate such complexity. In time a clearer picture will emerge.

Its a tough gig being an early explorer. From some reports, 95% of the first fleet to Australia died in the first year. London though this was a great success and sent more ships. Many other nations had previously tried, those that lived got accepted by the Aboriginal community.

originally posted by: Astyanax
a reply to: Arbitrageur

Certainty about what?

About which of two distinguished scientists is more likely to be right in their interpretation of JWST data.

In modern science, collaboration may still have errors, but I think it's less error-prone than solo work.

We are not really comparing two distinguished scientists. We have Chae who performed his work without any collaboration, versus an entire team of collaborators with Banik as the lead author:

Banik's collaboration team:
Indranil Banik (University of St Andrews)
Charalambos Pittordis (Queen Mary University of London)
Will Sutherland (Queen Mary University of London)
Benoit Famaey (Strasbourg Observatory)
Rodrigo Ibata (Strasbourg Observatory)
Steffen Mieske (European Southern Observatory)
Hongsheng Zhao (University of St Andrews)

So we might discuss the collaboration team of seven scientists, led by Banik, versus Chae's solo work, and the team of seven claim to have identified what they think are some issues with Chae's work (lack of Bayesian statistics and insufficient data quality filters). They even re-examined Chae's data with better filters in place to remove about 5000 of Chae's 26,500 data sets with the largest uncertainties! Figure 26 from the paper by Banik and his 6 collaborators is a very informative graph showing Chae's MOND effect goes away when those ~5000 data sets with large uncertainties are removed from the analysis:

arxiv.org...

The graph on the top has all of Chae's data using 26,615 data sets, showing a MOND type effect (line slopes up to the right), and the graph on the bottom filters out some data with high uncertainties, and that the remaining 21,049 data sets from Chae's work do not show a MOND effect, see how flat it is? If you don't find this convincing of an issue with Chae's work, why not? This is good science, so it's not a case where I would put the two papers on a balance and wonder which direction the weight of evidence might tip the scales, this tips the scales a lot in favor of the Banik paper, for me at least, and also apparently for the astrophysicist on youtube whose video is linked in the OP.

a reply to: Arbitrageur

Cut is how you want.. Dark matter / gravity, You dont know what it is.. Dont talk from a point of conviction when the underlying principles of your philosophy are still unproven.

a reply to: Arbitrageur

Just adding my unqualified opinion with the rest and that is that I will continue to keep jumping on every new shiny theory that comes along.

www.advancedsciencenews.com...

a reply to: Arbitrageur

My last furnace lasted thirty one years, maintenance on it was about three hundred bucks tops. My new furnace cost more than the original I put in and I had to actually hire a contractor to put it in and set it up. I could have put it in myself if there was not so much technology to hook up.

I am not complaining about the cost of replacing the furnace, but I was informed that there will be more maintenance and repairs and the new high efficiency furnace will only last fifteen years because the cost of repairing it will cost more than replacing it from that time on. I did not get the most efficient, I guess they are more unreliable because of more sensors and technology and the price was a grand and a half fore. Now, how do you save when the furnace only lasts half as long and the cost savings of the extra fuel does not justify the replacement cost. The same goes for the way they make appliances these days, I just bought a new washing machine, the last one lasted a little over seven years and it's repair cost is more than I paid for this new one. The savings I got from being more efficient does not even come close to the replacement cost. Before my last washer, the one we had lasted over twenty years with no maintenance. I guess you can still buy a good washing machine, like a speed queen at thirteen hundred bucks, but I do not plan on living another twenty five years anymore to justify the expense.

My riding lawn mower works pretty good, it does need a blade and belt, it was born in nineteen seventy seven. I did have to do some work on the wiring connections, but now it turns over great, but I have to figure out why it will not start, I should have removed the battery cable before doing that, I think I may have to replace the points or condenser...might have shorted them or something when some wires sparked. It is the original set of points and condensor, but before it ran out of gas, it was working great. Now, if I had bought a new one ten years ago, it would have been shot already, I know lots of people who had that happen. I have fixed things a lot over the years, I should have disconnected the battery before working on it. That's life. Or is it just laziness.

originally posted by: purplemer
a reply to: Arbitrageur

Cut is how you want.. Dark matter / gravity, You dont know what it is.. Dont talk from a point of conviction when the underlying principles of your philosophy are still unproven.

People knew electricity existed before all the underlying principles were understood. Ben Franklin was said to be doing lightning experiments without the slightest clue about electrons or the underlying principles of how electrons worked, which wasn't understood until over a century later. I see dark matter as sort of like that; we don't understand the underlying principles of it as you say, but as with Ben Franklin's lightning, we do seem to think we see "proof" of dark matter in the bullet cluster, or at least NASA claims so, and this is a widely held view:

Bullet cluster



Another fact which proves dark matter exists: You're standing on dark matter. The Earth is made of baryonic dark matter. The problem is, not all of the dark matter out there can be made of stuff like the Earth is made of.

It's almost impossible to prove something true, but it's not impossible to prove something false. So dark matter (or just about anything else) can't be proven true, but maybe the alternatives can either be proven false or highly unlikely. The elephant in the room with MOND that MOND supporters just seem to ingore, is that galaxy rotations aren't the only evidence for dark matter. Light is also being bent by gravity more than we can explain, and MOND doesn't explain that like dark matter does. That doesn't even come up in a comparison of the work of Chae versus Banik et al.

Another problem with MOND is that it can't explain observations of galaxies that appear to have no dark matter. With dark matter, there could be more in some galaxies than in others, but if you modify gravity, the modified gravity equations should apply to ALL galaxies, so MOND can't really explain why some galaxies seem to have less dark matter.

Does the Failure to Find Dark Matter Prove the Existence of Dark Matter?

We’ve been failing to detect dark matter for decades. Finally, the latest failure to detect dark matter may have actually proved its existence. One of these is true: either most of the matter in the universe is invisible and formed of something not explained by modern particle physics OR our understanding of gravity is completely broken. The debate over which is true has raged for decades, but may finally have been resolved in an unlikely way: the proof that dark matter exists, and really is an exotic, unknown substance, may have come from the discovery of two galaxies that appear to have no dark matter at all.

So if you argue that dark matter doesn't exist, how are you going to explain that result of galaxies being found which don't seem to have it? How are you going to explain gravitational lensing? How are you going to explain the bullet cluster? How are you going to explain the large scale structure of the universe? All these things are just ignored in the MOND papers I've read. They don't even try to explain them. This cosmological picture is much larger than a claim we are comparing one paper by Chae against abother paper by a 7 scientist collaboration.

Now if someone can come up with a model that is consistent with cosmological observations, that doesn't involve dark matter, I'm all for it. So from that perspective, I do not have any conviction about dark matter. However I don't see how it's going to be possible to explain all the cosmological observations without something like dark matter, that's where the evidence seems to be pointing. So I don't call that conviction either, I'm just following the evidence and going where it leads me, as the scientists seem to be doing. One thing to keep in mind is that we can barely detect neutrinos which mostly pass through the entire Earth as if it wasn't even there, billions pass through your body right now. If there are particles which are even harder to detect, there are no guarantees we can detect them at all. It's amazing we can detect neutrinos at all, and some portion of dark matter is probably actually neutrinos or something like them.

originally posted by: quintessentone
a reply to: Arbitrageur

Just adding my unqualified opinion with the rest and that is that I will continue to keep jumping on every new shiny theory that comes along.

www.advancedsciencenews.com...

The focal point of the papers being discussed in this thread is do we need dark matter to explain observations or could some modified gravity theory explain them. You linked a modified gravity theory, but the article says the scientists haven't really considered how dark matter fits into their model, so it doesn't help at all with the topic discussion. I can see the advantages of hypothesizing what happened at the big bang, because none of us was there when it happened to say it's wrong. But it's also hard to show it's right.

a reply to: rickymouse
I've crunched some numbers on the modern appliances versus old appliances and at least for the numbers I crunched, I tend to agree with your conclusions that the older appliances are more economical from a total cost perspective. The energy savings claimed are probably real, but I'm seeing lots of reports from repair technicians etc that older appliances which tended to last 20-30 years, modern versions probably only last 10 years or less. Even if it needs repair after 7 years, the repair may not make much sense if it costs a lot and some other component will break down in the next year or two, making you wish you had just replaced it instead of repairing it. I think modern appliances aren't built to last as long, and not made as easy to repair, among other things. I'm not sure what any of this has to do with this thread, but that subject would make an interesting separate thread.

a reply to: Arbitrageur

The focal point of the papers being discussed in this thread is do we need dark matter to explain observations or could some modified gravity theory explain them. You linked a modified gravity theory, but the article says the scientists haven't really considered how dark matter fits into their model, so it doesn't help at all with the topic discussion. I can see the advantages of hypothesizing what happened at the big bang, because none of us was there when it happened to say it's wrong. But it's also hard to show it's right.

Your words: "Since MOND was the most popular alternative to dark matter, (and I know some people don't like dark matter), then to explain observations, we are left with either dark matter, or else finding some other alternative theory besides MOND. There are some, but none that I know of had the widespread support that MOND did (note the use of past tense; if Dr. Becky is convinced, I don't think she's the only one)."

I won't offer any other theories if you want to keep the discussion only between the two conflicting MOND theories but I was misled to a certain extent on the subject matter including what you said above about finding other alternative theories besides MOND and in my mind that would be theories about everything and anything else.

a reply to: quintessentone
But that theory is completely silent so far on dark matter; does it need dark matter, or doesn't it? The authors don't even seem to know. If you read my quote you cited, I mentioned dark matter, or alternatives to dark matter and we can't even say where that theory falls because the authors of the theory apparently have no idea! So I'm not sure how that adds to the discussion about dark matter or alternatives, and doesn't it seem odd to you that they haven't even considered the dark matter question and how it does or doesn't fit into their model? They are going to look into it apparently, but that doesn't tell us anything now.

This theory has been out for a while, Laniakea. Trying to map what is exactly going on with our galaxies, looks like a good start.

Shot version


Long version

originally posted by: rickymouse
Is it really necessary to find out how it precisely works to live our life on this earth?

100% it does. Understanding the intrinsic nature of 'gravity', how it works, how to control it, even generate artificially in controlled locations, etc, means a revolution in human technology. That in turn means we can leave the Earth and travel the cosmos, possibly without the hinderance of FTL limitations and effects.


And finding new habitable planets - it's vital for our species to survive.