Mysterious Galaxy Without Dark Matter Puzzles Astronomers (cnet.com) 106
Astronomers say they've located six galaxies that appear to have either very little or absolutely no dark matter. The team will present its findings in Monthly Notices of the Royal Astronomical Society. CNET reports: Mentioning that they'd previously been told "measure again, you'll see there will be dark matter around your galaxy," the researchers zeroed in on one seemingly dark-matter-free region dubbed AGC 114905 to strengthen their evidence. Lurking 250 million light-years away from Earth, it's about the size of the Milky Way, with a thousand times fewer stars. So it's rather dim. The researchers used a standard technique to detect the presence of dark matter in AGC 114905 that involves graphing the position and rotation speed of the galaxy's gas. After 40 hours of scrutiny with the high-powered Very Large Array Radio Telescope in New Mexico, they found the movements of the gas were perfectly explainable by normal matter alone.
"The problem remains that the theory predicts that there must be dark matter in AGC 114905," Pavel Mancera Piñabut of the Kapteyn Astronomical Institute at the University of Groningenour and an author of the study, said in a statement, referring to classic dark matter hypotheses. "Observations say there isn't -- in fact, the difference between theory and observation is only getting bigger." One caveat, the team says, is that perhaps the angle at which they viewed AGC 114905 affected their observational results. "But that angle has to deviate very much from our estimate before there is room for dark matter again," Tom Oosterloo of Astron at the Netherlands Institute for Radio Astronomy and co-author of the study, said in a statement.
And if they're correct? The team offers up a few reasons for why AGC 114905 may not have any dark matter. For instance, what if super large galaxies nearby somehow stripped it of the force? As a rebuttal, though, Mancera Pinabut says there don't seem to be any such galaxies in the vicinity. Further, he says, "in the most reputed galaxy formation framework, the so-called cold dark matter model, we would have to introduce extreme parameter values that are far beyond the usual range. Also with modified Newtonian dynamics, an alternative theory to cold dark matter, we cannot reproduce the motions of the gas within the galaxy."
"The problem remains that the theory predicts that there must be dark matter in AGC 114905," Pavel Mancera Piñabut of the Kapteyn Astronomical Institute at the University of Groningenour and an author of the study, said in a statement, referring to classic dark matter hypotheses. "Observations say there isn't -- in fact, the difference between theory and observation is only getting bigger." One caveat, the team says, is that perhaps the angle at which they viewed AGC 114905 affected their observational results. "But that angle has to deviate very much from our estimate before there is room for dark matter again," Tom Oosterloo of Astron at the Netherlands Institute for Radio Astronomy and co-author of the study, said in a statement.
And if they're correct? The team offers up a few reasons for why AGC 114905 may not have any dark matter. For instance, what if super large galaxies nearby somehow stripped it of the force? As a rebuttal, though, Mancera Pinabut says there don't seem to be any such galaxies in the vicinity. Further, he says, "in the most reputed galaxy formation framework, the so-called cold dark matter model, we would have to introduce extreme parameter values that are far beyond the usual range. Also with modified Newtonian dynamics, an alternative theory to cold dark matter, we cannot reproduce the motions of the gas within the galaxy."
News Flash (Score:5, Funny)
Astronomers make observation that doesn't require Fudge Factor, get very confused.
"Duuude, who ate all the brownies???"
Re: (Score:2, Interesting)
Can anyone reproduce the behaviour using off-the-wall ideas like elecro-magnetic forces as described by the Electric Universe people? I know they claim to have created self-organising galaxies by simulation purely with electrical forces. If they can, they might have another 'win' to add to their collection.
Re: News Flash (Score:3)
Electric Universe is such an interesting explanation of a lot of connected aspects but it stills feels more like philosophy. I don't know if they have simplified the patterns they connect in any meaningful set of laws/rules. Am I mistaken? It also doesn't handle the BB if I recall right.
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Overall they make more qualitative observations than quantitative observations. That's not to say that a self-consistent model can't be formed using existing formulas (eg: Lorentz' aether model), there just hasn't been much mathematical talent dedicated in that direction.
Overall, the trend has been towards an increasing role of dielectric+magnetic forces on interplanetary+galactic scales. https://link.springer.com/arti... [springer.com]
Re:News Flash (Score:5, Insightful)
Actually this strengthens the claim that dark matter is real. If it was just a different gravity model, it couldn't be absent in some galaxies. While unlikely with dark matter, it is at least possible.
Re: (Score:3, Insightful)
It definitely doesn't strengthen anything if they're puzzled by it.
When they figure it out, then maybe.
Re: News Flash (Score:5, Interesting)
It definitely doesn't strengthen anything if they're puzzled by it.
This isn't how science works. Reality is, regardless of whether someone understands it or not.
The observation that dark matter effects are present in some galaxies and missing in others is one pice of evidence that favors a local cause (e.g. dark matter) over a general physical principle (e.g. adjustments to the law of gravitation). This is already true, right now, regardless of who's puzzled by it, how strongly they're puzzled, and whether they'll ever truly figure it out or not.
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The observation that dark matter effects are present in some galaxies and missing in others is one piece of evidence that favors a local cause (e.g. dark matter) over a general physical principle
This.
So the scientists shouldn't wring their hands in grief and say "measure it again". It's another data point. Perhaps they should be searching the observable universe for more combinations of dark vs real matter. And plot a curve. The search will be aided by the imminent launch of the JWST (Just Wait Space Telescope).
Re: News Flash (Score:5, Insightful)
So the scientists shouldn't wring their hands in grief and say "measure it again".
Indeed, but the scientists should wring their hands in doubt, knowing that many fundamental "discoveries" turned out to be measurement errors, and say "let's measure this again before we take the results seriously."
Re: News Flash (Score:2)
Indeed.
I didn't RTFA so I don't know how many times they did measure or whether they did publish in a peer-review journal. But whenever we got publishable results, even before we wrote the paper, on first contact of our data with any peer scientists, one of the first questions was "did you reproduce this?"
Another much softer question was "did somebody else in a different lab reproduce this?", but here the answer is mostly "no", since no other group or lab was able to successfully do this experiment so far;
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The first time these scientists came back with their measurement, saying "measure it again" was legit. They've now pushed the probability of error out far enough that "measure it again" loses to "revise the theory." Science requires a constant rebalance between those two principles.
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The observation that dark matter effects are present in some galaxies and missing in others is one pice of evidence that favors a local cause (e.g. dark matter) over a general physical principle...
This would make sense if we were talking about something on a much smaller scale. But what is a "local cause" in reference to an entire galaxy situated among other galaxies? If their observation had indicated that the galaxy had only a portion of the expected dark matter, then it would be easier to see it in these terms. But the observation was that it was entirely (or nearly entirely) lacking dark matter. If I come into the kitchen and am told that my daughter spilled sugar all over the floor, and I see it
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That makes no sense. If it's a gravity model that doesn't incorporate dark matter, then how could it not be absent?
For example, how do we know that spacetime is flat across the entire universe when not distorted by mass? If it varies across the universe, then some galaxies would behave differently from others.
Re:News Flash (Score:5, Interesting)
Now the main question is, if the observations of gravitational effects on galactic scales like the rotation curves of galaxies, the clustering of galaxies, the gravitational lensing strength of galaxies or the primordial clumping of matter as seen in the Cosmic Microwave Background, which differ from the predictions of General Relativity from the observable matter are local effects, mediated by matter we have no other signal of (hence nicknamed "Dark Matter"), or if General Relativity is wrong and need some amendments for galactic scales.
An observation on a galactic scale, which conforms much better to General Relativity than similar observations would contradict a fundamental flaw in General Relativity, but rather point to a fundamental flaw in our observations, e.g. there are effects out there we can't observe directly. It is easier to explain why a galaxy might have (nearly) no Dark Matter, as we have already seen in the Bullet Cluster, than it is to explain why our fine tuning of General Relativity (MoND, TeVeS et. al.) to calculate away the effects of Dark Matter fails for some galaxies.
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But how does this go against General Relativity? Let's suppose that spacetime is not flat everywhere (factoring in mass), and that this has been the case since the Big Bang. In most of the universe you'd see what you expect (as with Hubble pictures), but when you look at areas where artifacts of the Big Bang are present, then you wouldn't get the results you'd expect - as with this galaxy.
Doesn't that wind up being the same as having invisible "stuff" that is spread fairly evenly except for in certain areas
Re:News Flash (Score:5, Interesting)
We have two alternatives:
If some galaxies show no clear difference between model and observation, and others show quite large differences, then the idea that our observation is incomplete, gets more merit. If Dark Matter is actually a thing, then it is quite possible, that one galaxy contains more of that thing than another one.
Dark Matter still looks like a kludge, because now cosmologists can add as much Dark Matter as they need for each galaxy, and every galaxy might get a different amount of Special Sauce. On the other hand, the alternatives work even less.
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Ultimately, the problem is we haven't sent probes out to other galaxies to send signals back, so we can calibrate our long-distance observations.
At small distances, we have to calibrate our sensors before we can make a claim. At long distances, we say, "Well, we won't live long enough to get the answer of a calibration test, so we don't have to do one!" With no resultant down-grading of our certainty in the results.
We know really well about the small scale, but it only takes a tiny unknown physical law at t
Re: (Score:3, Funny)
I push dark matter out of my black hole practically every day. The gravity model pulls it down into what results in a swirling vortex, like a spiral galaxy. I've known this is real since I was three.
3 years old (Score:2)
You were age 3? What took you so long to come to that level of understanding of the underlying physics?
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It's because that galaxy is not being energy-mined by the Grizzelians because it's deemed sacred. Prove me wrong!
Re: News Flash (Score:3)
Here's a deeper Mystery (Score:5, Funny)
Pavel Mancera PiÃf±abut
Professor Piña also wonders why /. still doesn't have proper unicode support, but ultimately found it easier to tackle the mystery of why an entire galaxy is missing dark matter.
Re: Here's a deeper Mystery (Score:2)
One thousandth! (Score:5, Insightful)
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No, you're not the only one.
Re:One thousandth! (Score:5, Informative)
Am I the only one that gets annoyed when people state things as a multiple less than something?
Am I the only one WHO gets annoyed when people use the relative pronoun THAT to refer to individual people?
Yes I know it's grammatically acceptable, but it's really grating...
Re: One thousandth! (Score:2)
Re: One thousandth! (Score:2)
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Am I the only one that gets annoyed when people state things as a multiple less than something? Not one thousand times less. That's nonsensical. It's one thousandth. You could even say 0.1%.
It's the inverse operation of "one thousand times more", I don't see why it should be a problem.
You don't translate idioms word-by-word between English and Spanish, why would you do it between English and Mathematics?
Re: (Score:3)
Because it's "one thousand times as much" not "one thousand times more". </pendantry>
Re: One thousandth! (Score:2)
It's not nonsensical. It's clearly defined. If A is 1000 times more than B, B is 1000 times less than A. You should probably adjust your understanding instead of getting annoyed with your something over your own mental framing.
Re: One thousandth! (Score:2)
Blame it on the shipping crisis (Score:5, Funny)
First, there was a shortage of cream cheese in NYC.
Now, there's a lack of dark matter in the galaxy.
Re: Blame it on the shipping crisis (Score:3)
It's a conservation law combined with a measurement principles. Cream cheese is white, dark matter is er dark. Therefore the observation of a lack of dark matter made the cream cheese disappear. It's just the new cycle is backwards because we obviously care more about cream cheese.
Now I am no phitist but I know how these works, so you can keep the noble prize for me.
Astronomy is cool (Score:1)
Re:Astronomy is cool (Score:5, Insightful)
It doesn't disprove it, but it does throw a spanner in the works. If the theory makes a prediction and the prediction is falsified in even one case, the theory is incorrect as stated. In some cases, you can salvage the theory. In other cases, you can't. Here, there is a clear prediction that there would be Dark Matter. There isn't any. Nor is there any clear way for the Dark Matter to have been removed. That is a serious problem for the theory. However, it's possible that Dark Matter can be fixed, you just need to change how Dark Matter appears in the universe so that it's not automatic that a galaxy will obtain some.
It's worse for MOND, though. I like MOND. To me, the best case would be if you needed both Dark Matter and MOND, just less of each, because then a lot of other anomalous situations become easy and it becomes much easier to explain why Dark Matter is so hard to observe. However, here, MOND cannot account for the behaviour, even in weakened form. Everything looks to be behaving as expected when using classical gravity. I don't see how that could be anything other than disastrous for MOND.
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It doesn't disprove it, but it does throw a spanner in the works. If the theory makes a prediction and the prediction is falsified in even one case, the theory is incorrect as stated. In some cases, you can salvage the theory. In other cases, you can't. Here, there is a clear prediction that there would be Dark Matter. There isn't any. Nor is there any clear way for the Dark Matter to have been removed. That is a serious problem for the theory. However, it's possible that Dark Matter can be fixed, you just need to change how Dark Matter appears in the universe so that it's not automatic that a galaxy will obtain some.
It's worse for MOND, though. I like MOND. To me, the best case would be if you needed both Dark Matter and MOND, just less of each, because then a lot of other anomalous situations become easy and it becomes much easier to explain why Dark Matter is so hard to observe. However, here, MOND cannot account for the behaviour, even in weakened form. Everything looks to be behaving as expected when using classical gravity. I don't see how that could be anything other than disastrous for MOND.
Now I regret the mod points I squandered earlier. This comment is an absolute gem and needs +1 Insightful, because +5 fucking brilliantly clear explanation isn't an option.
Re: Astronomy is cool (Score:2)
I really want to hear the potential solutions to why dark matter may not exist in some galaxies. One of the explanations is neutrinos if I recall right, so maybe there is a manner in which neutrinos production is reduced locally. However, if I recall right the explanation of dark matter as neutrinos is one of the weaker theories.
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I have also heard one theory that dark matter consists of small primordial black holes. If we assume that the density in primordial times would have to have been pretty high to have created black holes along the size of a few atoms, than an area with a low density galaxy, and no large galaxies around would be very likely to have less of them.
Not a Physicist, just an interested observer, so I could be way off base on it.
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I have heard this too but I think the footing it has right now is similar to the idea of neutrinos being involved. In both regards much more data needs to be collected and we likely will need ever better experimental apparatus to come to any certainty about which is a better explanation.
Clearly both are very interesting.
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In the case of the Bullet Cluster, it's ram pressure stripping. Two clusters collided, and the dark matter just went flying straight through, without any collisions or dissipation of momentum, while the baryonic matter clumped in the middle and got hot, because of collisions. It's exactly what you'd expect for a mixture of frictionless and friction-observing objects.
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Right so one explanation seems to be "stripping" the dark matter. This was mentioned in the article via a much more massive nearby galaxy but they said no such galaxy was observed. In the case you describe, it's a collision which again doesn't seem to be the case here. So while "stripping" could be possible via some other mechanism we might also conclude there is some reason locally dark matter would be "generated" at a significantly lower rate. In this regard, it seems like it could have something to do wi
MOND? (Score:1)
If the observation is confirmed, how will MOND explain it?
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Since gravity seems to be behaving purely classically, MOND is going to have extreme difficulty. I find that a shame, I would far prefer to end up with both Dark Matter and MOND as it simplifies a lot of problems and explains a lot of the anomalies. However, if there's a case where no modification to gravity is required, that looks pretty fatal for MOND. MOND would have to apply equally everywhere.
Maybe dark matter doesn't exist (Score:3)
Perhaps the anomalous rotation of our galaxy and others is down to perhaps as yet unidentified defects in space (other than black holes) that matter collected around and it just so happens this galaxy came together under gravity alone.
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There are about 11 independent types of observational evidence that support it: https://en.wikipedia.org/wiki/... [wikipedia.org]. If it were only one or two then there would be lots of room for alternatives. Since so many lines of evidence all point to massive stuff that doesn't interact with light, it's now nearly certain there's some form of clear, massive stuff really out there.
Dark matter. It's not just for galaxy rotation curves anymore (TM).
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My theory is that it's warp propulsion pollution of some sort, like in that one ST:TNG episode. Either these galaxies have never been explored by FTL travel or something/someone there is harvesting it somehow.
What if physics made a mistake? (Score:1, Funny)
It is starting to look like physics is broken in some big way. I lost faith when mass, length and time had to be adjusted to explain away the results of the Michelson–Morley experiment. Because the alternative would have been to admit the Earth was indeed at the center of the entire universe.
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Theoretical physicist will solve the universe one day. They will have no proof for anything though.
Re: What if physics made a mistake? (Score:5, Insightful)
Physics is never "broken", just as Newtonian mechanics was never broken, and Kepler's laws before it weren't broken, either.
What we have is always models, never Truth(tm). Once you get experiments that don't fot the currenttly most advanced model, you get a glimpse of what lays behind it. Once you're smart enough, inspired enough, or both, you come up with a new model that explains the new stuff. If you're really, really lucky, then you come up with a model that covers the old stuff, too, while explaining the old stuff.
There's really nothing else to it. Truth(tm) is for the philosophers, mathematicians, the Gods, Slashdotters... but not for Physics.
Re: What if physics made a mistake? (Score:2)
I think I need another coffee. So many typos I can't handwave away by claiming "typing on a phone" alone... -_-
Explaining existing results a requirement (Score:3)
If you're really, really lucky, then you come up with a model that covers the old stuff, too, while explaining the old stuff.
That's actually a requirement, not an optional extra. If your model is inconsistent with the old stuff then it is wrong and clearly does not explain anything, old or new.
Re: Explaining existing results a requirement (Score:2)
If your model is inconsistent with the old stuff then it is wrong
The first question about a model is not whether it's "right" or "wrong", but whether you're moving "inside" or "outside" of its scope. Therefore a model is never "wrong" (or always is, whichever way you prefer). It's just limited in scope. Your model can, but needs not necessarily, fully cover the scope of an earlier model. If it does, good for you: your model is more general. If it doesn't, don't sweat it. It's just a model within a more or less narrow scope.
Again, a "model" is not "truth". It was never su
Re: (Score:2)
The first question about a model is not whether it's "right" or "wrong", but whether you're moving "inside" or "outside" of its scope.
When you are doing fundamental physics everything is in-scope - you are trying to come up with a model that explains the universe. That's how we know the Standard Model is ultimately wrong because there are phenomena like gravity that it cannot explain.
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When you are doing fundamental physics everything is in-scope - you are trying to come up with a model that explains the universe.
Well, you can be as ambitious as you like and set the scope of your model as wide as you like. But this doesn't mean that it's Physics that has a problem or is somehow "broken", as OP put it. Whether you really do need to put "everything" in scope, that's a matter of debate.
In the current debate, it's about gravity and dark matter, so a new model better cover gravity, in particular the astronomical observations surrounding it, at least as well as the existing one(s).
(BTW, "fundamental physics" to me means s
Re: Explaining existing results a requirement (Score:2)
I think you should substitute theory some places you say model but otherwise your comments are on point.
This is necessary because models can be horse shit. Not like saying the earth is flat or a geocentric model. Instead more like a model that would explain how 5G causes Covid-19. I think we can agree such a model could be constructed but it would be total bullshit for reasons left to the reader.
Re: (Score:2)
I think you should substitute theory some places you say model but otherwise your comments are on point.
I've heard the distinction many times before, but to this day I have no idea where one ends and the other begins :-)
To me, a "model" used to be whatever fits some data, while a "theory" is something you'd derive out of a set of principles -- i.e. a proposal for a (new) set of "laws of nature". So a model would be the "DIY dirty survival field version" of knowledge, while a theory would be the "cleaned-up, properly designed, engineered, commercial version". So to speak.
But then again, the Standard Model, the
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Fair enough. Your points are more than valid.
This being said, the lack of being able to test new predictions in String Theory is why it's dead but it's sounds consistent to the predictions of other Theories/Models. However, since it's more complex, there is "no need" for it yet.
In my mind, all theories are built on models though as you said, they generally have explanations that can written out as laws relative using relatively straightforward English. We can do this with General Relativity at least. The St
Re: (Score:2)
Sorry, too early in the morning. A bit of word salad there ;(
Re: Explaining existing results a requirement (Score:2)
I don't think it's about the degree of "rightness" ot not. There are plenty of unproven theories - it's basically the bread and butter of theoretical physicists, and they're more often wrong than right by a large margin.
I have the feeling it's more something like: a model extrapolates or (e.g. from earlier data) a theory predicts (e.g. based on assumptions). They can both fail or hold. But a model is more an "empirical" description, while a theory is more of a guessig attempt at the the underlying truth and
Re: (Score:2)
Yeah. I feel your explanation might be more on point.
Specifically when you say a theory predicts base on assumptions. From physics I remember hypothesis to theory, in the sense that when we perform an experiment, we should try to make an initial predict and if these hold then that hypothesis can get the "foundation" of being a theory. This is where I am come from in a sense of "rightness". The "wrongness" seems to often relate to how common/fair the assumptions are. There was another post here today about r
Re: (Score:2)
Look at the thermodynamic model of black body radiation. There were two other models, the Raleygh-Jeans-law and Wien's model, for low and high energy emissions. None expands on the other. None is more "general" than the other. Yet they are models. They are not wrong, they just have limited scope.
Rayleigh-Jeans law is most definitely wrong - by an incredibly impressive factor at higher energies. Just because a model is a useful approximation under certain circumstances does not mean that it is not fundamentally wrong as a description of reality. Planck's law fixed the problem by giving us a fundamental insight into EM radiation that led to a mathematical prediction that works. We know that Newtonian mechanics is fundamentally wrong in the way it deals with space-time but it is still a useful approx
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Doesn't Newtonian mechanics get things wrong by an incredibly impressive factor at higher energies also?
Re: (Score:2)
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Yes - but Rayleigh-Jeans gets the spectrum spectacularly (basically infinitely!) wrong for all sources of black-body radiation
Yes, and the small-angle approximation gets sinus wrong for essentially all circles. Except at... small angles :-)
Joking aside, Rayleigh-Jeans is "wrong" if your expectation is that it should (kind-of) work for the complete spectrum. But that was never going to work, it was a model based on a flawed understanding of radiation. Its limitations were well-known at that time.
Rayleigh-Jeans is "not wrong" in the scope that if can at least describe parts of the spectrum at low energies.
I know we're arguing semant
Wrong, but "good enough" (Score:2)
A model can explain data in a specific range with a specific precision, in which case it is "not wrong" for exactly that scope
Yes, it is still wrong. Physics is not mathematics: a physics model is not just a set of equations but a conceptual understanding of how the universe works that we use to derive mathematical relationships. The maths from a wrong model may agree with your data under certain circumstances given a sufficient lack of precision in your measurements but the concept behind how they were derived is simply wrong.
The only way how a model can be outright wrong is if it doesn't match any data
I agree...and since Newtonian mechanics will fail in every situation if you measure with enough precisi
Re: (Score:2)
In Newtonian mechanics, the speed of gravity is infinite, which is infinitely faster than the speed of light. There's also the whole issue of objects with mass travelling at the speed of light (or indeed faster) and the energy required to get there, etc. but the speed of gravity issue is really a problem at all energies. It really seems like the vast majority of the matter in the universe is in systems that don't conform in any way with Newtonian mechanics.
So I don't really see that much of a distinction be
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> A Physics model is more than just fitting data to a curve.
But a physics doctorate is exactly that, right? ;-)
Re: (Score:2)
But a physics doctorate is exactly that, right? ;-)
Only if the linear fit is based on more than 2 points *gnihihi*
Re: (Score:2)
Rayleigh-Jeans law is most definitely wrong - by an incredibly impressive factor at higher energies.
...which was pretty much my point. Raileigh-Jeans does not do a good job of describing high-energy radiation, and Wien doesn't get the low energies right. That's because the respective models are out of scope.
Just because a model is a useful approximation under certain circumstances does not mean that it is not fundamentally wrong as a description of reality. Planck's law fixed the problem [...]
Every model is "fundamentally wrong" as a description of reality as soon as a better model comes along and extends its scope. Even electromagnetism is a "fundamentally wrong description of reality" when you go to energies high enough to interact with the weak force.
What do you do when the Unified Formu
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Not always. Quantum mechanics and gravity are incompatible somehow, but for now we use each in its specialized domain and we make progress in both areas. We might find a new domain where neither QM nor G apply and come up with a specialized theory that applies only there, and that might let us develop fabulous technologies that only work there until someone figures out how to unify all the models. But in the meantime, the new model fails to account for the old, yet still has scientific value.
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Neither of these is mainstream physics. Probably never will be, either.
Re:What if physics made a mistake? (Score:5, Interesting)
That's silly. What's happening is that some prospective theories are accumulating evidence against them. That's how physics works: theories are presented, evidence is collected, they get tested. Even the standard model of particle physics, as a theory, is not considered fully done. In fact, it cannot be because there is much it doesn't explain. We use it because no one has come up with anything better. However, we never stop trying. Sooner or later it will be replaced by something better.
Actually, string theory has had a number of successes. It merely fails to explain everything so in your estimation it has failed. Scientists don't consider an entire theory failed if parts of it succeed (see Newton's theory of gravity). I don't know from where you got your views of science, but they were not from scientists.
Re: (Score:2)
Actually, string theory has had a number of successes. It merely fails to explain everything so in your estimation it has failed.
The problem with String Theory is that it fails to explain anything and so cannot fail. It's not really a theory so much as an idea, a beautiful idea and one definitely worth pursuing, but barring some incredible breakthrough one that is still very far from being a theory with testable predictions.
Re:What if physics made a mistake? (Score:5, Interesting)
Thing is that nobody has done a full General Relativity simulation of galactic rotation yet. By that I mean solving the field equations at each step.
What they do is use Newtonian Mechanics to simulate galactic rotation with a relativity "fudge" Because this simulation didn't match observations they invented dark matter to fix the problem. I will admit that a full General Relativity simulation of a galaxy requires tying up an exascale HPC facility for several months so is currently not practical but that is no excuse for what astronomers have done.
Add in the can't detect dark matter; well that's shades of the "ether" right there. The alarm bells should be deafening. On top of that despite making up the majority of the mass of the Universe, magically there is none anywhere near our solar system. At this point the smell of rotten fish should be gut wrenching.
The whole dark matter/dark energy thing is beyond bad science IMHO.
Re: What if physics made a mistake? (Score:3)
You mean like this?
https://link.springer.com/arti... [springer.com]
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If it were only galactic rotation, you'd be correct, but we have evidence of dark matter from many other data sources, sources that we can model in greater detail. When it started, it was only a patch for galactic rotation, but we are a decade past that being the primary rationale for DM. A complete model of rotation might help us figure out DM, but we don't need it anymore to postulate DM.
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The whole dark matter/dark energy thing is beyond bad science IMHO.
So, I agree with everything you wrote, but then the quote above.
Dark Matter is just a "variable". It is an 'X' in an equation that is trying to be solved. People who think 'X' is real thing are guilty of Bad Science. People who understand that Dark Matter is really just a variable in an equation and that it might not be an 'X' but rather a deeper equation itself that must be solved to return 'X' are doing Science.
Re:What if physics made a mistake? (Score:4, Insightful)
Relativistic explanation for gravity creates the need for dark matter which doesn't exist
That is wrong, has nothing to do with relativity.
We see Galaxies far away, that rotate faster than they should: hence some unknown force (which basically can only be gravity, which implies the galaxy is heavier than it looks from counting the stars) pulls it together and keeps it rotating quicker.
What if you learn some physics first? (Score:4, Insightful)
I lost faith when mass, length and time had to be adjusted to explain away the results of the Michelson–Morley experiment. Because the alternative would have been to admit the Earth was indeed at the center of the entire universe.
Before you lose faith in physics perhaps it would be good to first learn some first. The alternative explanation was that the Earth was somehow dragging the aether around with it. The problem with this is that there would then have to be some boundary between the dragged aether and the non-dragged aether which would create some optical effects and nobody could find any.
Also mass does not have to be adjusted at all. Mass is a Lorentz invariant which is the same for all people in all inertial frames and Einstein himself warned about the fallacy of "relativistic mass". The gamma factor in relativistic momentum comes from the changes to space-time which impacts the definition of velocity, not mass.
As for string theory and supersymmetry proposing theories that solve problems or inconsistencies in the models of reality we have is how we make progress. We then go and look for evidence of them and, if we cannot find any, then we drop the idea and look for another explanation. This is how science works. Expecting theorists to only come up with the right answer every time is just silly - if they could do that there would be no need for experiments to see which ideas are right!
Indeed, for me the miracle of physics is that theorists can come up with the right answers at all. Of all the infinite possibilities to explain why fundamental particles have mass Higgs came up with the model that was, as far as we can tell so far, absolutely correct. Why should the solutions which appear the simplest and most elegant to our minds be the ones that the universe operates by?
dark matter all the way down (Score:3, Funny)
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No mod points but virtual +1 for the parent
Spelling or copy/paste? (Score:3)
However, an interesting and puzzling observation.
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Seems obvious to me (Score:5, Funny)
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Snard snarked:
The intelligent race that inhabits that galaxy has simply mined it all. It makes great starship fuel, after all.
Wish I had mod points. You'd get a +1 Funny for that ...
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It's legal to dump overboard as long as you're more than 24 AU from the nearest inhabited planet or habitat, and cut into one inch cubes or smaller. Yes, they still use inches for this law.
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Strong proof of time travel viability is the fact that the English inch is the basis of galactic law. The only other option is some really screwy convergent entomology!
A galaxy where dark lives don't matter? (Score:2, Flamebait)
Supply chain? (Score:2)
The supply chain problems are getting absurd.
Finally a Kardeshev Type III Civ! (Score:2)
Perhaps this is what a Kardeshev Type III civilization looks like. A Type II civilization can only harness the energy of its own star, but a Kardeshev Type III civilization can do so for a galaxy. Which is why one of the methods hypothesized as noted below is, "They may also be able to tap into the energy released from the supermassive black holes believed to exist at the center of most galaxies." Sounds like a galactic level energetic process involving Dark Matter exists! ;)
https://en.wikipedia.org/wiki/.. [wikipedia.org]
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Maybe they use dark matter to power the super gates. They are on their way here next. All Hail the Ori.
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Maybe they were like, "Screw it. We don't understand the physics, so I want all this Dark Matter moved out of here so that just once before I die all the equations work." :-)
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You think a galactic civilization is successfully collapsing its dark matter halo into black holes which it can then feed off of? I think this is far from proven or even from being the most likely explanation, but it would be an extremely interesting discovery if true. Dark matter can be consumed by black holes but very little of it apparently gets caught because of its inability to shed angular momentum due to being frictionless.
Experiments! (Score:3)
Dyson Spheres? (Score:1)
Bullet cluster (Score:2)
This is probably too obvious a solution, but it seems like galactic collisions like the famous Bullet Cluster could account for something like this. The Bullet Cluster is often held up as one of the strongest pieces of evidence for dark matter: two galaxies that collided, where the normal gas and dust mostly stopped in the collision while the majority of the mass, mostly dark matter, passed through each other. Fast-forward a few billion years and the dark matter will be in a different part of the sky entir
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two galaxies that collided, where the normal gas and dust mostly stopped in the collision while the majority of the mass, mostly dark matter, passed through each other.
So dark matter is a kind of matter that, while it 'creates gravity', i.e. curves space-time, it doesn't move in the same manner that other matter does due to that curve.
Perhaps Howard Tayler can shed some light on this (Score:2)
My theory: in that galaxy, the dark matter sophonts lost their war against the baryonic sophonts and evacuated. There's a big cloud of dark matter between that galaxy and a neighbor but you can't see it because it's dark.