What are you looking for here? It looks to me like you are objecting to the "immateriality" of the explanatory concepts of modern physics. Is it your premise that all of the working parts must be in some way comprehensible in terms of things (e.g., fluids) that are familiar to us from everyday experience? Why should this be the case? We understand perfectly well now why the kinds of things we are (in the terminology of modern physics, made of baryonic matter on a scale in between atomic and cosmological) experience the world the way we do and fail to perceive certain aspects of reality.
What do you think about neutrinos? There are billions of them going unnoticed through your body every second. Is it a mistake for modern physics to treat them as the explanation for energy conservation in beta decay, to use them as probe of the nuclear reactions in the core of the sun, or as evidence of distant violent cosmic events?
Right. I think you got it correct. The galaxy is rotating faster than the visible mass can explain (The observation). The Invention: We need a sphere of invisible stuff called a "Dark Matter Halo" to provide the gravity to hold it together. It feels like a circular argument, where there's nothing to question since the model is correct because the measurements fit the model, and the model predicts these measurements.
If you are a doctor and you see a patient with high blood pressure, you measure the pressure. You don't "invent" an invisible, undetectable demon that is squeezing the arteries. You look for the mechanism, diet, stress, genetics. Dark matter is essentially "invisible demon" physics. It fixes the math, but it lacks a mechanism. My text is proposing a mechanism, rather than circulating the formulas around reality.
We have zero (little?) evidence of dark matter outside of the gravitational anomaly itself. If it were truly "matter," it should have some other signature (heat, friction, interaction with light) like the neutrino. The fact that it interacts only with the very anomaly we are trying to fix is exactly why I am skeptical of it and where my example is a good one (I believe). I love the neutrino idea, because it does match my thoughts that the scale determines the action and the forces that matter in the scale. I say the apple cares about our lifting it, but the cells inside it won't until you reach a certain RCF. They'll care (interact at an energy level) with phosphates, but not neutrinos.
The lack of observational evidence for DM in any form is the reason why theories like MOND are still bumping around out there. But also, the argument for DM is not circular. It goes in a straight line: galaxy rotation curves, the detailed structure of the cosmic background radiation, the observations of the rate of cosmic expansion, gravitational lensing from galaxy clusters and your bullet cluster example and probably some others I'm forgetting -> there is some kind of non-baryonic matter out there interacting gravitationally. There's no circularity. There is a gap - we don't know what the DM is made of, which is where you've found space for your ideas. (I brought up neutrinos because the evidence for them is so indirect, though now quite firmly grounded.)
Long ago I worked as an assistant for a guy who was looking for MACHOs (massive compact halo objects, a joke on the already-coined WIMPs). They still might not yet be completely ruled out but quickly fell out of favor due to observational constraints like lack of nearby solar-scale lensing events (the things he was looking for). My point is just that people have thrown a lot of ideas out there and if you're not working in the field, and read only popularizations, you might have no idea what's been looked at and ruled out, and why.
All that said, if you want to engage seriously with the physics community (maybe you don't) you have to genuinely engage with the mathematical framework and the details of the evidence. There are mathematical models of fluid dynamics out there and somehow your model has to capture what they say, or explain why it doesn't apply.
Your professional community has a problem with untrained people showing up with just a little knowledge about biology and grand theories about what the "real" problem underlying illness is. Seed oils! Lectins! Misaligned qi! Vaccine denialism! Sometimes they make videos and become "influencers" and then the PCPs tear their hair out about dealing with all the misinformation. I won't say you're a physics quack because you clearly do want to engage with the evidence, but it's a lot harder than it might look. You can't just throw some mechanical picture out there and expect people to pick it up and engage with it until you do the work to explain how it meets the observations, and that work has to be in the language that physicists use, which is mathematical. If you're being honest with yourself, I think you don't even know if your ideas can meet the data without working through the math. That's been the lesson of physics since at least Kepler.
But the equations are not just made out of thin air, they are based on observation. We are not bending reality, we are describing it. What you just outlined is basically the mainstream definition of dark matter, you just called it fluid. An invisible “ocean” of matter that surrounds everything is one of the accepted possible explanations for dark matter. It’s just very inert and therefore elusive to detection.
To explain why I lean toward a fluid-dynamic alternative, think about the Encontro das Águas (the meeting of the Rio Negro and Solimões rivers - google it, if you haven't been). They run side-by-side for miles without mixing, creating powerful, anomalous currents and eddies at their boundary. If an observer only knew the physics of solid mechanics and didn’t understand fluid dynamics, they might look at those anomalous boundary forces and calculate that there must be ‘invisible underwater boulders’ holding the rivers apart and altering the current.
But there are no invisible boulders. It is just fluid mechanics, differences in speed, density, and friction creating a physical boundary layer. A fish can cross (and I did myself) between them, even though there are occasional whirlwinds.
When we measure a ‘dark matter halo’ around a spiral galaxy, what if we aren’t measuring an invisible sphere of particles? What if we are measuring the hydrodynamic boundary layer, a massive cosmic whirlpool, generated by the galaxy spinning within the cosmic fluid? The fluid wake provides the inward pressure to keep the outer stars in equilibrium, just like a current.
The only new thing we'd need are the properties of the fluid that composes the universe locally (like air, we ignore in formulas, but exists and has properties and molecules and they do change it locally).
FBoondoggle | a day ago
What are you looking for here? It looks to me like you are objecting to the "immateriality" of the explanatory concepts of modern physics. Is it your premise that all of the working parts must be in some way comprehensible in terms of things (e.g., fluids) that are familiar to us from everyday experience? Why should this be the case? We understand perfectly well now why the kinds of things we are (in the terminology of modern physics, made of baryonic matter on a scale in between atomic and cosmological) experience the world the way we do and fail to perceive certain aspects of reality.
What do you think about neutrinos? There are billions of them going unnoticed through your body every second. Is it a mistake for modern physics to treat them as the explanation for energy conservation in beta decay, to use them as probe of the nuclear reactions in the core of the sun, or as evidence of distant violent cosmic events?
[OP] polidorobio | 7 hours ago
Right. I think you got it correct. The galaxy is rotating faster than the visible mass can explain (The observation). The Invention: We need a sphere of invisible stuff called a "Dark Matter Halo" to provide the gravity to hold it together. It feels like a circular argument, where there's nothing to question since the model is correct because the measurements fit the model, and the model predicts these measurements.
If you are a doctor and you see a patient with high blood pressure, you measure the pressure. You don't "invent" an invisible, undetectable demon that is squeezing the arteries. You look for the mechanism, diet, stress, genetics. Dark matter is essentially "invisible demon" physics. It fixes the math, but it lacks a mechanism. My text is proposing a mechanism, rather than circulating the formulas around reality.
We have zero (little?) evidence of dark matter outside of the gravitational anomaly itself. If it were truly "matter," it should have some other signature (heat, friction, interaction with light) like the neutrino. The fact that it interacts only with the very anomaly we are trying to fix is exactly why I am skeptical of it and where my example is a good one (I believe). I love the neutrino idea, because it does match my thoughts that the scale determines the action and the forces that matter in the scale. I say the apple cares about our lifting it, but the cells inside it won't until you reach a certain RCF. They'll care (interact at an energy level) with phosphates, but not neutrinos.
FBoondoggle | 5 hours ago
The lack of observational evidence for DM in any form is the reason why theories like MOND are still bumping around out there. But also, the argument for DM is not circular. It goes in a straight line: galaxy rotation curves, the detailed structure of the cosmic background radiation, the observations of the rate of cosmic expansion, gravitational lensing from galaxy clusters and your bullet cluster example and probably some others I'm forgetting -> there is some kind of non-baryonic matter out there interacting gravitationally. There's no circularity. There is a gap - we don't know what the DM is made of, which is where you've found space for your ideas. (I brought up neutrinos because the evidence for them is so indirect, though now quite firmly grounded.)
Long ago I worked as an assistant for a guy who was looking for MACHOs (massive compact halo objects, a joke on the already-coined WIMPs). They still might not yet be completely ruled out but quickly fell out of favor due to observational constraints like lack of nearby solar-scale lensing events (the things he was looking for). My point is just that people have thrown a lot of ideas out there and if you're not working in the field, and read only popularizations, you might have no idea what's been looked at and ruled out, and why.
All that said, if you want to engage seriously with the physics community (maybe you don't) you have to genuinely engage with the mathematical framework and the details of the evidence. There are mathematical models of fluid dynamics out there and somehow your model has to capture what they say, or explain why it doesn't apply.
Your professional community has a problem with untrained people showing up with just a little knowledge about biology and grand theories about what the "real" problem underlying illness is. Seed oils! Lectins! Misaligned qi! Vaccine denialism! Sometimes they make videos and become "influencers" and then the PCPs tear their hair out about dealing with all the misinformation. I won't say you're a physics quack because you clearly do want to engage with the evidence, but it's a lot harder than it might look. You can't just throw some mechanical picture out there and expect people to pick it up and engage with it until you do the work to explain how it meets the observations, and that work has to be in the language that physicists use, which is mathematical. If you're being honest with yourself, I think you don't even know if your ideas can meet the data without working through the math. That's been the lesson of physics since at least Kepler.
BitcoinMD | a day ago
But the equations are not just made out of thin air, they are based on observation. We are not bending reality, we are describing it. What you just outlined is basically the mainstream definition of dark matter, you just called it fluid. An invisible “ocean” of matter that surrounds everything is one of the accepted possible explanations for dark matter. It’s just very inert and therefore elusive to detection.
[OP] polidorobio | 7 hours ago
Thanks for the comment and I don't disagree.
To explain why I lean toward a fluid-dynamic alternative, think about the Encontro das Águas (the meeting of the Rio Negro and Solimões rivers - google it, if you haven't been). They run side-by-side for miles without mixing, creating powerful, anomalous currents and eddies at their boundary. If an observer only knew the physics of solid mechanics and didn’t understand fluid dynamics, they might look at those anomalous boundary forces and calculate that there must be ‘invisible underwater boulders’ holding the rivers apart and altering the current.
But there are no invisible boulders. It is just fluid mechanics, differences in speed, density, and friction creating a physical boundary layer. A fish can cross (and I did myself) between them, even though there are occasional whirlwinds.
When we measure a ‘dark matter halo’ around a spiral galaxy, what if we aren’t measuring an invisible sphere of particles? What if we are measuring the hydrodynamic boundary layer, a massive cosmic whirlpool, generated by the galaxy spinning within the cosmic fluid? The fluid wake provides the inward pressure to keep the outer stars in equilibrium, just like a current.
The only new thing we'd need are the properties of the fluid that composes the universe locally (like air, we ignore in formulas, but exists and has properties and molecules and they do change it locally).