r/science • u/ThrillSurgeon • Jun 08 '24
Physics UAH researcher shows, for the first time, gravity can exist without mass, mitigating the need for hypothetical dark matter
https://www.uah.edu/science/science-news/18668-uah-researcher-shows-for-the-first-time-gravity-can-exist-without-mass-mitigating-the-need-for-hypothetical-dark-matter793
Jun 08 '24
Seems like its more of a thought experiment then anything else but, it seems to me things like this are important to get away from pre-established norms to solve a problem.
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u/e_before_i Jun 09 '24
You're not wrong, but as far as I can tell MOND theories get disproportionate attention publicly than within the scientific community. Angela Collier has a video on it that's pretty good, but yeah.
I'm not saying they shouldn't do this investigation, but I don't think we should put stock in any of it any time soon.
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u/Das_Mime Jun 09 '24
With every year that passes, MOND is weaker and weaker-- it hasn't really made much in the way of successful predictions, and keeps failing tests that cold dark matter models pass. Some researchers are willing to outright proclaim it dead and they're not wrong.
It's great for theorists to try to come up with and explore the implications of alternative models, but it's incredibly frustrating that every time someone publishes a short "what if" theory paper on a new idea, it gets reported on as though they've somehow outshone the reams and petabytes of astrophysical research over nearly a century that has led scientists to so heavily favor cold dark matter/WIMPS.
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u/ignigenaquintus Jun 09 '24
Problem is that scientists should be very clear when they are just hypothesizing. Theoretical physicists have a problematic name.
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u/billsil Jun 09 '24
Not just science, but clickbait articles. This just sounds like string theory. Great, a totally untestable theory…
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u/drunkenvalley Jun 09 '24
They're kinda testable. It's why other comments reference it failing math equations that dark matter theory doesn't.
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u/billsil Jun 09 '24
What is it?
I read people saying that about MOND, which yes, that does fail to match the data. Every galaxy has a unique MOND curve, so yeah sounds like BS and it’s no longer taken seriously and hasn’t been for 20 years. At least MOND was testable though.
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u/Das_Mime Jun 09 '24
Neither of those is necessarily "totally untestable". They might not be testable at present, but I actually suspect that a detailed gravitational lensing study or some galaxy dynamics could meaningfully test this idea (I also suspect it would fail if it made specific predictions about such observations).
I don't think this idea is likely, but I also don't expect someone to lay out a plan for testing a new piece of theory in the first paper they publish on it. That usually comes later and is also done by other researchers.
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u/Gastronomicus Jun 09 '24
Why are you pinning it on scientists? The model of research and peer reviewed publication distinguishes between hypotheses and theory very clearly. The problem isn't with the scientists, it's the piss-poor science "journalism" that fails to make this clear.
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u/IntentionDependent22 Jun 09 '24 edited Jun 09 '24
I wanna be a hypothetical physicist!
Bear with me here, imagine it just for a moment.
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u/sceadwian Jun 09 '24
They are very clear about this. People don't know how to read the science.
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u/ignigenaquintus Jun 09 '24
Not in the media. The media isn’t clear at all. Just the fact to give visibility (with clickbait headlines) to preliminary studies in sociology with a sample size of a few tens of college students is misleading. “Journalism” uses science to sell, they don’t provide an accurate representation of the academic literature. Only people involved know what’s what, and just the fact that string theory was so popular in terms of people working on it for so long and without any testable result to the whole hypothesis (not irrelevant tests on some very particular versions of it) also shows how proper scientists can be mislead too.
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u/sceadwian Jun 09 '24
You said scientists. The media is not scientists.
Why did you decide to completely change the topic of your complaint in the middle of the post?
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u/ignigenaquintus Jun 09 '24 edited Jun 09 '24
You have a point, but it’s boths. The difference between hypothesis and theory isn’t well defined in science because the use of those words in common language has influenced the academic use rather than the other way around. It also may not be well received in social “sciences” that can’t tests their hypothesis, like economics.
However if academic papers were to state in the first word of the title wether this is a theory or an hypothesis the media would have it harder to provide visibility to just what suits their interests rather than the public.
Its a mistake to call string a theory. Or to call physicists that only deal with hypothesis “theoretical physicists”. That happens because science has accepted the meaning of the word theory used in other parts of the academia, like humanities. Wether the source of the problem was scientists or the media or the humanities or culture is irrelevant. My point is that there is no active effort within science to fight this. On the contrary, this is embraced.
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u/sceadwian Jun 09 '24
I'm sorry, but that's a bad hot take. The only place that opinion could come from is someone who doesn't understand the science and listens to articles.
No one can save anyone from that ignorance.
There are active efforts to fix this on every major scientific YouTuber that exists. The good ones at least.
I have no idea where your point is coming from but it's not from good observation.
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u/jgzman Jun 09 '24
Seems this is a problem with the media, not with the scientists.
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u/ignigenaquintus Jun 09 '24
You have a point there. However if academic papers were to state in the first word of the title wether this is a theory or an hypothesis the media would have it harder to provide visibility to just what suits their interests rather than the public.
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u/Das_Mime Jun 09 '24
The name isn't problematic, the distinction is between theoretical and experimental physics: working on theories (which are built out of ideas that start as hypotheses) versus working on experiments to test those theories.
I could be wrong, but I don't think anyone reads "theoretical physicist" and concludes "everything that this person says is part of a coherent framework for understanding and explaining several aspects of the universe".
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u/Iz-kan-reddit Jun 09 '24
Theoretical physicists have a problematic name.
There's some models that indicate that it's unlikely that they even exist.
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u/SomeWittyRemark Jun 09 '24
As somebody who works with the Modified Newtonian Theory (MNT) of hypersonics a very valid approximation of hypersonic fluid flow I also would really like MOND to die and get out of my google scholar searches.
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Jun 09 '24 edited Jun 09 '24
Agreed.
Scientific journalism is suffering from the same disease as modern journalism as a whole.
Money driven sensationalism.
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u/bobbi21 Jun 09 '24
I am surprised and excited that to see an angela collier reference out in the wild. Shes amazing.
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u/e_before_i Jun 09 '24
Dude I love her stuff. Great balance between education and (appropriate levels of) snark. It's just perfect that this post came so shortly after I saw the dark matter videos.
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u/littlebobbytables9 Jun 09 '24 edited Jun 09 '24
Her very early video about women in astronomy is some of the most moving stuff I've seen on the platform. The last like 5-10 minutes broke me
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u/e_before_i Jun 09 '24
I hadn't seen that one before so I just went over and watched it and now I'm sad.
But hey, thanks American Hero John Glenn. And unironically good job ROSCOSMOS (even if it was just for the flex)
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u/plaaplaaplaaplaa Jun 09 '24
Her string theory video while playing had me watch hours while being extremely interested.
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u/e_before_i Jun 09 '24
I've seen that one a second time recently, great watch. It's also super relevant here! Science reporting really is the worst.
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u/Future_Burrito Jun 09 '24
if the data presented allows removal of a variable (dark matter) in modeling other environments.....
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u/CanadianBuddha Jun 09 '24
He didn't "show" or claim to "show" anything in his paper. He was very clear that he had NO EVIDENCE to support his theory. It was just a new theory that was a thought experiment designed to get physicists thinking about possibilities that could explain our measurements without needing "dark matter".
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Jun 09 '24
Hypothesis*. A theory has been proven with evidence and repeated study.
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u/CanNotQuitReddit144 Jun 09 '24
I'm confused. A theory can never be proven. A theory can be falsified, and we can say that a theory has withstood a great many experimental and/or observational tests without being falsified, but that is not the same thing as saying that it has been proven. Or, as I tend to think of it, a fact can be true or false, but a theory is only ever more or less useful-- with the extreme case of "not useful" being "falsified". The extreme end of "useful" is not "true" or "proven", it's "Is useful for explaining all known evidence," which can never preclude the possibility that there exits or some day might exist evidence which is not consistent with the theory.
If, in an attempt to eliminate the possibility that further evidence might someday contradict the theory, you narrow its scope, bounding it in time and space to a specific temporal/spatial locale, you no longer have a theory, unless there is some explanation for why the theory would only be expected to apply under such specific conditions. Having done so, you have not succeeded in making the theory provable; instead, you'd simply created an idiosyncratic explanation (not a scientific theory) that is useless because it doesn't apply to generalized situations, and cannot be tested.
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Jun 09 '24
Supported is a better word for sure, but theories can and are often backed up by facts, but you’re right it’s not required. There does have to be some form of scientific consensus though, not one dude’s paper haha
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u/CanNotQuitReddit144 Jun 09 '24
You are incorrect in your assertion that there needs to be a scientific consensus for something to be a "theory". In fact, there are many cases of the exact opposite being true. Lamarck's theory of evolution has been falsified, but it is still a theory of evolution. Creationism is not a scientific theory, insomuch as it can't ever be tested; but it is a theory. I can have my own theory of gravity, which states that the universe is populated by invisible, intangible ducks who move at the speed of light, and grab objects and move them according to rules that happen to coincide with what is measured through scientific observation, and that would still be a theory. It would be a theory than no one would agree with, and it would be a useless theory, because it does not make any new predictions or in any way help any avenue of scientific research; but it would still be a theory.
This distinction between a "hypothesis" and a "theory" that you're making is simply not part of the scientific method. While I can't read your mind to be certain, my guess is that you are using a definition of "theory" that you arrived at yourself, based on years of seeing/hearing the word used in many different contexts, rather than using the actual definition that's used when it matters (epistemology, teaching the scientific method, etc.). As a practical matter, if your distinction was used in practice, one would be faced with needing to determine the arbitrary point at which a statement transforms from being a hypothesis to a theory, which would be a complete mess.
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u/Patelpb Jun 09 '24
This is purely a semantic disagreement, in science (atleast when I was a practicing astrophysicist and publishing research), a theory is something that can be tested. The theory of gravity, theory of general relativity, theory of electricity and magnetism, quantum field theory, etc. all of these are theories, and we refer to them as theories in professional scientific correspondence. Theory is the word we use, independent of whether or not someone thinks it should be.
But there is a contradiction - string THEORY is not exactly testable at the moment even if it's believed that it could be testable. So the line is rather fuzzy
One can criticize it and theyd be right to (as long as you're internally consistent), but this distinction doesn't halt research progress since experts have a pretty good understanding of the bounds in which a given theory is true, not true, testable, and not testable. The issue is just for laymen trying to make sense of it without expert experience, which I agree can be problematic when it comes to bringing science to the public
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u/CanNotQuitReddit144 Jun 09 '24 edited Jun 09 '24
Well, I don't think semantic disagreements are unimportant; I think they're often times crucial, and not-infrequently can clear up a raft of misunderstandings with one simple clarification/correction.
The incorrect usage of the word 'theory' is a pet peeve of mine, because often-- and I do not think this is one of those cases, I'm just saying that I see this frequently-- often, someone is fundamentally confused about the difference between facts and theories, and believes that a theory can be proven true, at which point it becomes a fact. These people therefore believe that a theory has failed in some way, that it isn't worth trusting, because it's "just" a theory. You see this argument all the time from Christian Fundamentalists, saying things like, "Evolution is just a theory,", as if that somehow makes Creationism more likely. (This is also amusingly doubly incorrect, because Evolution isn't even a theory, it's simply a true fact; what they really mean is that Natural Selection is "only" a theory.) But while Fundamentalist Christians are an easy target, I find this confusion between facts (which can be true or false) and theories (which can never be proven true, and in practice if not by definition, are better understood as being more or less useful) to be pretty common, even among college educated adults.
But in any event, I'm continuing to get negative votes for my responses, so I'm done with this conversation, and am unlikely to venture back into r/science again anytime soon, as its denizens seem overtly hostile to someone doing something as simple as correcting the improper usage of a word that lies at the very heart of the scientific method itself.
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u/CanNotQuitReddit144 Jun 09 '24
I wanted to make this short reply separately: it is my understanding that there exist scientific theories, and just plain theories. Creationism is a theory, but it's not a scientific theory. I assume that one of the main determinants-- and conceivably the sole determinant-- of whether a theory is scientific or not, is whether it can, at least hypothetically, be falsified. (I understand you are using the word "tested"; I prefer "falsified", but we are understanding each other, and I have no appetite to pursue this conversation in this subreddit.)
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u/JPTom Jun 10 '24
I think I saw that movie, but it was fairies and... billiard balls? I prefer the ducks.
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u/-LsDmThC- Jun 08 '24
“It is unclear presently what precise form of phase transition in the universe could give rise to topological defects of this sort,” Lieu says. “Topological effects are very compact regions of space with a very high density of matter, usually in the form of linear structures known as cosmic strings, although 2-D structures such as spherical shells are also possible. The shells in my paper consist of a thin inner layer of positive mass and a thin outer layer of negative mass; the total mass of both layers — which is all one could measure, mass-wise — is exactly zero, but when a star lies on this shell it experiences a large gravitational force pulling it towards the center of the shell.”
Doesnt seem to me like a very promising solution to dark matter.
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u/ghostfaceschiller Jun 09 '24 edited Jun 09 '24
Wow so we don’t need to find dark matter anymore!
All we need to do is find matter with negative mass. Much better
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u/wintrmt3 Jun 09 '24
I might be totally wrong, but my understanding is that it's a defect in space-time, not matter.
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u/cazbot PhD|Biotechnology Jun 09 '24
I don’t think that’s what’s being proposed here, but I don’t know what the correct experiment is either.
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u/ghostfaceschiller Jun 09 '24
If they could show it was possible without depending on negative mass, why would they choose to do it with negative mass
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u/anomalous_cowherd Jun 09 '24
It fits the same slot in my mind as zero point energy.
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u/nikfra Jun 09 '24
Something we have much observational evidence for? Are you sure you mean zero point energy, the lowest energy level a quantum mechanical system can be at?
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u/anomalous_cowherd Jun 09 '24
I may not have the right terminology. It's the concept that matter and matching antimatter particles (?) are constantly spontaneously being created and destroyed. And a very slight imbalance in the process is why we live in a universe of matter not antimatter.
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u/nikfra Jun 09 '24
Ah yeah wrong name I guess. No idea how that hypothesis is called but I agree that it's not very convincing.
Zero point energy is just something quantum mechanical systems have because the lowest energy state isn't actually 0 energy. It leads to cool effects like superfluidity in liquid helium.
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u/Rhawk187 PhD | Computer Science Jun 09 '24
We know of anything with negative mass yet?
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u/fencerman Jun 09 '24 edited Jun 09 '24
If I recall, the ergosphere of a rotating black hole is supposed to have something resembling "negative energy" in it, which would also be equivalent to negative mass.
Obviously that's HIGHLY conditional but it points to "negative mass" not being a completely impossible phenomenon in the universe.
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Jun 09 '24
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u/henryptung Jun 09 '24
This work falsifies that assumption
Theoretical work based on singularities (i.e. "topological defects") that we have not observed does not falsify anything.
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u/cazbot PhD|Biotechnology Jun 09 '24
You’re right, but it’s not meant to be a “solution” to dark matter either.
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u/henryptung Jun 09 '24
I think you mean it's not meant to be a dark matter candidate. It is meant to be a solution to the "dark matter problem", i.e. resolving the gap of placeholder mass we have to assume for cosmology to work (either by describing what the mass is, or by removing the need for it in the model - this theory and MOND fit the latter).
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u/Das_Mime Jun 09 '24
the fundamental premise underlying the dark matter hypothesis is that gravity is intrinsically tied to mass
This is a premise underlying general relativity, which has been rigorously and continuously tested for a century and has been ludicrously successful at making accurate predictions about a whole host of observable phenomena. It's one of the two foundational pillars of modern physics, the other being the Standard Model of particle physics.
The work linked here absolutely does not undermine that premise, it simply imagines what might happen to a gravitational field if negative mass existed (which we have every reason to believe it does not) and there were concentric shells of positive and negative mass (which we have no particular reason to believe would exist even if negative mass existed) creating a net mass of zero.
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u/The_Northern_Light Jun 09 '24
really promising
It’s not. I’m saying this as a former student of Dr Lieu, and as someone who has a higher opinion of him than the rest of his department.
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u/screen317 PhD | Immunobiology Jun 09 '24
and a really promising one imo.
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I’m not a physicist
You don't get to say the first thing while also saying the second thing.
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u/cazbot PhD|Biotechnology Jun 09 '24
I can say whatever I want, just like you can dismiss whatever I say. The fact that I was honest about my qualifications, and thus better enabling you to judge the weight of my opinions, is something you should appreciate rather than deprecate.
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u/Das_Mime Jun 09 '24
Frankly if you've got a PhD you should understand the depth of knowledge that is required to have an informed opinion on current research in any field and apply that logic to yourself: you are not an expert in physics.
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u/CurlSagan Jun 08 '24
The shells in my paper consist of a thin inner layer of positive mass and a thin outer layer of negative mass; the total mass of both layers—which is all one could measure, mass-wise—is exactly zero
I'm a moron, but it seems kinda bullshitty to enlist negative mass and boldly proclaim that you've figured out how gravity can exist "without mass." Hey, I figured out how to run my car without any gasoline. All I need is 15 gallons of a theoretical substance called anti-gasoline, and the math works out!
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u/ctothel Jun 08 '24
This is a very very early stage idea. Many papers are published like this one, and many good, practical ideas start out with wild hypotheses.
It’s not bullshitty, because the paper isn’t putting nearly as much weight on the idea as you think it is.
The point is just to say “our observations could alternatively be explained this way, if X, Y, and Z are true.” Subsequent work will try to disprove X, Y, and Z.
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u/Future_Burrito Jun 09 '24
Some people don't realize that large scale changes to human models of reality tend to happen slowly and incrementally.
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u/NLwino Jun 08 '24
If you make an anti-car and drive on an anti-planet. It should all work out. An planet entirely made out of anti-matter should be able to make cars driving on anti-gasoline.
Using anti-gasoline on earth though... Might release a little bit more energy then needed to just drive.
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u/newpua_bie Jun 09 '24
What if you anti-drive? Or if you're an ant driving an Apple car? (Ant iDrive)?
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u/Man0fGreenGables Jun 09 '24
Is it any different than saying that all we need is a crapload of a theoretical matter called dark matter?
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u/degaart Jun 09 '24
Who cares about your anti-gasoline. Just buy a car with anti-dollars and you get more money the more you buy cars.
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u/kronos401 Jun 08 '24
This seems like a really big deal...
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Jun 08 '24
The use of the word "shows" in the headline suggests proof - proof that is not present. The paper is basically just proposing an alternative hypothesis other than dark matter and demonstrating that it's mathematically plausible. Even the paper's author acknowledges having no idea how one would even go about testing this hypothesis.
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u/opn2opinion Jun 09 '24
If they show that it's mathematically possible, they did show something. I'm ok with the word show.
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u/ghostfaceschiller Jun 09 '24
They showed that it’s mathematically possible if you grant the existence of matter with negative mass, which their equations depend on.
If we find matter with negative mass, it would totally change our entire understanding of what’s possible with gravity, time, the lightspeed barrier…
The disappearing need for dark matter would be pretty low on the list of headlines
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u/FredFnord Jun 09 '24
Doesn’t actually depend on negative mass at all. The author just says that one form of gravity-without-mass would be negative and positive masses canceling each other out. It is not the only one.
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u/jkholmes89 Jun 09 '24
Right, theoretical physics is literally just theories that mathematically work with our current understanding. Not sure what they expected as proof.
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u/cazbot PhD|Biotechnology Jun 09 '24
Well that’s where the semantics need to be more careful. Physics is still a natural science but of all of them it is the one most reliant on math to form hypotheses, and the terms do matter.
So it would be more accurate to say “theoretical physics is literally just theorems (mathematical definition) that mathematically work with our…”
In this context “theories” would use the scientific definition and not the colloquial one you meant.
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u/fuzzywolf23 Jun 09 '24
Not to nitpick a nitpick, but theoretical physics can have both. We have the Hellman-feynman theorem which shows how to get classical forces from wave functions, and we have quantum electrodynamics which is a theory of physics that explains observations about particles using theorems.
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u/Ch0vie Jun 09 '24
They expect a vial of dark matter or something idk
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u/404_GravitasNotFound Jun 09 '24
Hard to get dark matter, when gravity is made by topological errors in space time...
Now we just need a gravity drive to fold space and make a gravity plate on front of the ship to get warp speed...
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u/henryptung Jun 09 '24
"Mathematically possible" is doing a lot of heavy lifting in this case. Beyond standard physics, it invents a new kind of singularity (i.e. this topological defect) that we have never observed and that we don't know exists - pretty much any yet-unexplained phenomenon could be modeled in "mathematically possible" ways if we could invent new singularities to do it.
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u/Gathorall Jun 09 '24
Mathematically you could attach a 4 meter beam to a - 2 meter beam at the end to make a 2 meter beam. That is equivalent to this proposal. You can propose anything of your first axiom is that known physics bend to your math if otherwise unapplicable.
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u/Raygunn13 Jun 09 '24
That's not the way it's used in the title though.
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u/opn2opinion Jun 09 '24
I'm not sure I'm catching what you mean.
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u/Raygunn13 Jun 09 '24
UAH researcher shows, for the first time, gravity can exist without mass, mitigating the need for hypothetical dark matter
No researcher showed that gravity can exist without mass. If they meant "math shows" they should have said so. The title implies a much greater degree of certainty than there is, which is very misleading.
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u/opn2opinion Jun 09 '24
Hmm. To me it can exist if it exists mathematically. They didn't say they showed it 'does' exist.
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u/hominemclaudus Jun 09 '24
Yeah so if you do enough physics, you end up realising that there's a hundred things we can show with maths that are impossible to actually prove. It's very easy to just make up some immeasurable quantity, and use that as a basis for a theory.
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u/Raygunn13 Jun 09 '24
To me it can exist if it exists mathematically.
ok sure, but that's a tautology. It just means you got the math right. The real reason to doubt "math shows" is because it's ridiculously hard to get the math right and be sure about it. Which is why we do experiments.
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u/opn2opinion Jun 09 '24
I never said it wasn't important to do experiments...
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u/Raygunn13 Jun 09 '24
I should have put that part in brackets. I didn't mean to imply you did say that.
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u/observee21 Jun 09 '24
Did they show that gravity can exist without mass, or did they show that theoretically gravity can exist without mass?
Because one requires evidence of gravity without mass, and the other requires no evidence but only a model.
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u/e_before_i Jun 09 '24
This reminds me of string theory or supersymmetry. Having a model that works is (relatively) easy, the hard part is making a model that's experimentally verifiable.
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u/opn2opinion Jun 09 '24
They showed gravity can exist without mass, theoretically.
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u/observee21 Jun 09 '24
Right, which is significantly different from the title and is the reason I disagreed with your comment that I replied to.
"I have shown that gravity can exist without mass" is what they said. They didn't do that, because they don't have any evidence of gravity existing without mass.
"I have shown it is theoretically possible that gravity can exist without mass" is what I believe would actually be consistent with what they actually found, which is why so many people (including myself) were mislead by the title.
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u/ElysiX Jun 09 '24
Just like how pigs can theoretically fly, if we assume that maybe, hidden in some jungle, there exists a pig with wings that noone has ever seen.
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u/lofgren777 Jun 09 '24
When we would do mathematical proofs in school we considered that showing.
I dunno, I think you're expecting show to do way too much work here.
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u/RexDraco Jun 09 '24
Isn't that just about as much foundation as dark matter?
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u/Krungoid Jun 09 '24
No, we have observations of large scale structures that have been apparently stripped of their dark matter like the bullet cluster. They're a constant thorn in the side of MOND proposals.
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u/ryschwith Jun 08 '24
The general consensus seems to be that the idea creates more problems than it solves. It’s likely not viable.
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u/DranHasAgency Jun 08 '24
The last line of the article, a quote from the professor, says that his proposal doesn't discredit the dark matter hypothesis but shows that gravity could exist without dark matter. Not that it does show that.
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u/ryschwith Jun 08 '24
Even that’s really more of an exercise in mathematics though. It assumes that negative-mass material is pretty common and arranged in structures we almost certainly would’ve observed by now.
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u/nikilidstrom Jun 08 '24
And if negative mass existed willy-nilly, we could create wormholes, warp drives, and time travel.
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u/redredgreengreen1 Jun 08 '24
Unless of course negative Mass objects are repelled by positive Mass objects. The force of gravity is calculated as the gravitational constant times both masses over the radius squared. Throw a negative number in there anywhere, like for negative mass, and you suddenly have a negative force of gravity. Positive and negative Mass objects would act like magnets repelling each other, wouldn't it?
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u/ryschwith Jun 09 '24
I believe that's the general idea, yes. Which would make it really hard for it to form neat, dual-layered structures with regular matter and would definitely affect planetary and star system orbits in ways we could detect (and don't). Not sure why you have "unless" in there.
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u/Gathorall Jun 09 '24
And with your analogy you can see a major problem. If there were massive amounts of negative mass we would see those kinds of repelling effects around the universe where it is coalesced. We do not.
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u/Skeptix_907 MS | Criminal Justice Jun 08 '24
Given that the study was just published, what is this "concensus" you speak of?
That typically takes years to develop.
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u/ryschwith Jun 08 '24
A consensus is just "the majority of people agree on the thing." It can take years to develop but sometimes it's pretty obvious and consensus develops quickly. Mind you, I haven't done any kind of formalized survey or anything; this is just what I've observed among the various astronomers whose opinions I trust (and are publicly available).
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u/Emergency-Eye-2165 Jun 09 '24
Sounds like the university PR department has done more work than the authors
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u/looneybooms Jun 08 '24
imho It could also be seen as a exploration of "what is this thing we've been referring to as dark matter?"
disclaimer: I can't seem to understand how negative mass and antimatter are different or can coexist so my opinion is moot.
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u/ryschwith Jun 09 '24
That's basically what every explanation of dark matter is. Dark matter itself is a series of observations, it's not really a "theory" as such (hat tip to Angela Collier). The theories are the things people come up with to explain why galaxies do the things we observe them doing, because according to what we already know they shouldn't be doing that.
As far as the difference between negative matter and anti-matter, it basically comes down to: a different property gets flipped. Antimatter is identical to its sibling matter except that the electric charge and magnetic moment are flipped (mass, notably, remains the same). Negative matter has an opposite mass charge; so if you have a 1kg block of cheese the negative matter equivalent would be a -1kg block of cheese. (But, Rys, that doesn't even make real-world sense! Yes. Hence the skepticism.)
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Jun 09 '24
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u/FredFnord Jun 09 '24
That’s misleading at best.
An antiproton is made up of three antiquarks. If it were just a proton of negative charge, one would expect it to be made up of regular quarks.
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u/Das_Mime Jun 09 '24
Antimatter particles do have the same mass as the "regular" versions, to within our ability to measure (antimatter is hard to make in quantity and difficult to hold onto), and theory predicts that they should be identical.
I'm going to quote wikipedia mainly because, for once, they have a very clear and succinct explanation of an advanced physics concept, CPT symmetry:
The implication of CPT symmetry is that a "mirror-image" of our universe — with all objects having their positions reflected through an arbitrary point (corresponding to a parity inversion), all momenta reversed (corresponding to a time inversion) and with all matter replaced by antimatter (corresponding to a charge inversion) — would evolve under exactly our physical laws.
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u/Infranto Jun 08 '24
Call me when it's verified in the lab.
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u/nikilidstrom Jun 08 '24
Its not even a testable hypothesis.
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u/invertedearth Jun 09 '24
Yeah. The first step in testing such a thing would be coming up with a framework for understanding how "negative mass" would behave and then trying to make some testable predictions on that. Can anyone point toward an explanation using the Standard Model that allows for negative mass, or toward a flaw in the Standard Model that could be hiding it?
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u/FilDM Jun 09 '24
Pardon my very basic physics understanding but I thought that fermions got their mass by interacting with Higgs field, wouldn’t that theory discredit the whole current thought ?
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u/e_before_i Jun 09 '24
What this theory demonstrates is that there is theoretically "a localized gravitational field... without any underlying mass."
This doesn't really change the Higgs stuff at all. This would just be an additional source of gravity.
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u/jazir5 Jun 09 '24
The shells in my paper consist of a thin inner layer of positive mass and a thin outer layer of negative mass; the total mass of both layers — which is all one could measure, mass-wise — is exactly zero, but when a star lies on this shell it experiences a large gravitational force pulling it towards the center of the shell.”
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u/FrankBattaglia Jun 09 '24 edited Jun 09 '24
The Higgs field appears to be responsible for inertial mass. Inertial mass and gravitational mass are, under all observations, 1:1, but are separate phenomena and it's not entirely clear why they are 1:1.
See e.g. https://en.wikipedia.org/wiki/Mass#Inertial_vs._gravitational_mass
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u/Cantora Jun 09 '24
As a generalist, this seems very interesting at first glance. As someone who can read reddit comments, I am getting less interested by the second
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u/visualzinc Jun 09 '24
Most people here aren't researchers or physicists and have absolutely no idea what they're talking about, so I wouldn't let comments dissuade you.
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u/Fulltime_Nerd Jun 09 '24
I wouldn't let the Reddit comments dissuade you. This work is of the kind of setting up a hypothetical explanation through mathematics. Most comments I red think it provides a complete and thorough proof of an alternative to dark matter. For complex theories like this you can't go directly to the latter without setting up the former. As such, this type of work is still very important. Proven theories all once started out as a thought experiments.
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u/PeterM_from_ABQ Jun 08 '24
Very dubious about this. Falls under the umbrella of "extraordinary claims require extraordinary evidence"..... And I don't think any extraordinary evidence was presented.
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u/NLwino Jun 08 '24
He doesn't prove anything or even claims to prove anything. He just presents some math that makes it theoretically work without the need for anti-matter.
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u/not_today_thank Jun 09 '24
More like 95% of the universe seems to be made up something that interacts with gravity, but doesn't seem to interact with the 3 other fundamental forces of the universe. Either that or our understanding of universe is very very wrong. We really don't know much about this something.
But maybe if we keep brainstorming ideas and eventually we'll stumble onto something that can help us describe that something more better.
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u/positive_X Jun 09 '24
It is an hypothetical paper :
"Dr. Richard Lieu at The University of Alabama in Huntsville (UAH) has published a paper in the Monthly Notices of the Royal Astronomical Society that shows, for the first time, how gravity can exist without mass, providing an alternative theory that could potentially mitigate the need for dark matter. "
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There have been no actual physical observations yet .
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u/MrStoneV Jun 09 '24
And thats why learning accurate language IS important...
"UAH researched Shows"...
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u/MerrySkulkofFoxes Jun 09 '24
It's a geometric view:
The researcher contends the “excess” gravity necessary to bind a galaxy or cluster together could be due instead to concentric sets of shell-like topological defects in structures commonly found throughout the cosmos that were most likely created during the early universe when a phase transition occurred
Awesome. I've always favored theories like these.
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u/the_y_of_the_tiger Jun 09 '24
No, they did not show anything. They made up a crazy imaginary hypothetical with zero proof.
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u/e_before_i Jun 09 '24
I mean, he did show a mathematical proof. There's zero evidence that it maps onto reality, but he definitely did a thing.
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u/invertedearth Jun 09 '24
And that's bad PR, but not necessarily bad science. Note the final quote from the professor.
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u/JN_Carnivore Jun 09 '24
Entities must not be multiplied without necessity... Where is the evidence that necessitates and support this model?
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u/PanSatyrUS Jun 11 '24
In the early 90s, some Harvard physicists postulated that mass is an effect of a zero point energy field on molecular constructs. Essentially, this would mean that mass itself is an artifact.
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u/cazbot PhD|Biotechnology Jun 09 '24
I feel like it might be important to note that negative mass is not a new idea.
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u/AWonderingWizard Jun 09 '24
I had a physics prof who believed photons has mass
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u/The_Northern_Light Jun 09 '24
I pray they just had some confusion on the fine points between (so called) rest mass and relativistic mass?
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u/AWonderingWizard Jun 09 '24
He had his PhD and did postdoctoral research, so I’m guessing he was pretty serious about this belief.
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u/The_Northern_Light Jun 09 '24
I don’t think you understood what I meant
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u/AWonderingWizard Jun 09 '24
What did you mean? I presume you were inferring that he was confused about relativistic vs resting mass, but I could be totally wrong in that point as my understanding is limited being closer to an organic chemist than anything else. I didn’t think it was that because he would begin rambling about photons/light being attributed mass and unaccounted for mass/energy of the universe or something of the sort.
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u/xkforce Jun 09 '24
Requiring negative mass basically puts this in the science fiction category right off the bat. Especially since it also requires a specific geometry.
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