4 ms·

Dark matter is just a theory hallucinated by computational models. It is and has always been defined as nothing but "where matter could be to explain the gap be

by uoaei 3y ago

Dark matter is just a theory hallucinated by computational models. It is and has always been defined as nothing but "where matter could be to explain the gap between model and data" but no good reason is ever given as to why it could be matter and not anything else. You can do the same thing with the solar system to "explain" a geocentric universe if you wanted.

JumpCrisscross 3y ago
> no good reason is ever given as to why it could be matter and not anything else Man, astrophysics and finance are not this forum’s strong suit. See the bullet cluster observations [1]. Explain it simultaneously with most galaxy’s spins, but also NGC 1277’s [2], without using dark matter. [1] https://en.m.wikipedia.org/wiki/Bullet_Cluster https://en.m.wikipedia.org/wiki/Bullet_Cluster [2] https://en.m.wikipedia.org/wiki/NGC_1277 https://en.m.wikipedia.org/wiki/NGC_1277
- uoaei 3y ago
  Far from settled: https://arxiv.org/abs/1003.0939 https://arxiv.org/abs/1003.0939 But armchair physicists love to shriek 'bullet cluster' every time because they aren't aware of the extent of their ignorance. Considering your HN bio I'd comfortably classify you as "knows just enough to be dangerous". Fair, given your generalization knowing nothing about me? More reading for your benefit, from a working astrophysics professor specializing in ultra-diffuse galaxies: https://tritonstation.com/2016/12/23/crater-2-the-bullet-cluster-of-lcdm/ https://tritonstation.com/2016/12/23/crater-2-the-bullet-clu... https://tritonstation.com/2017/03/06/lcdm-has-met-the-enemy-and-it-is-itself/ https://tritonstation.com/2017/03/06/lcdm-has-met-the-enemy-... https://tritonstation.com/2016/07/30/missing-baryons/ https://tritonstation.com/2016/07/30/missing-baryons/
  - deleted 3y ago
    [deleted]
  - JumpCrisscross 3y ago
    Lots of ground between settled science and “no good reason is ever given.” There are strong arguments for dark matter (broadly, not just Lambda CDM). They are inconclusive. The bullet cluster is less strong evidence for dark matter than good evidence against common armchair refutations. (I agree with your author that it doesn’t rule out MOND as is commonly claimed.)
    - uoaei 3y ago
      The arguments inevitably and only boil down to "look, our model converged". The point is, dark matter is not a theory, just a supposition that can always be "proven" with conveniently arbitrarily flexible models (no one can see it so it might be anywhere!). There is no positive theory that has been brought out to explain dark matter, only mere deductive hypothesis about where it would be. Deduction needs a culprit so people keep reaching for different kinds of particles. Jury's out on whether they exist but keeps the experimentalists employed, so at least it's worth that much.
      - JumpCrisscross 3y ago
        Fair enough. I think it’s qualitatively different from SUSY, where I tend towards your conclusion of jobs programme masquerading as theory. (I’m much less convinced dark matter is a novel particle.)
      - jboy55 3y ago
        There have been actually many positive theories trying to explain what particles dark matter could be, they've all been proven wrong. To me dark matter came about from this, "As we understand gravity we can postulate how galaxies rotate given an estimate on its mass, galaxies do not rotate like this" In this statement there are three elements; 1) Our understanding of gravity 2) Our estimates of the mass of galaxies 3) Our ability to determine how galaxies rotate. At one point in time this last 100 years, we had "solved" gravity with regards to our solar system, and we were finding so many new particles that #2 seemed like a great explanation. However, we are now left with no room in our understanding of particles, I think its time to look at the other elements. Put it this way, if we had never observed the galaxy, but developed the standard model in isolation. Then we looked at the stars and tried to define gravity, I'm not sure we'd be so quick to introduce a new type of matter to define gravity.
wanda 3y ago
The good reason for adding dark matter, that you say is absent, is one that is more a question of philosophy of science, in that adding more mass accounts for the observed behaviours without changing the known laws of physics. The known laws of physics have been formed on math that checks out and is consistent with all our other observations, and has made many predictions that have checked out and even formed the basis for technology that we use every day. The way science works is that we form mathematical models of physical behaviour, we test model against real world data, and if the model is consistent with reality, and predicts further behaviours that we then can test for, the theory behind it holds water and we have something to work from. If you like, you can think of it as building trust in a model, having courage in a theory isn't a mistake, it's how science has been built. Of course finding the errors and new laws is important, but you have to conclusively rule out the established theory first. This is how we got to Newtonian mechanics instead of firmaments, elements, worlds of forms and mythologies, and how we got to medicine instead of humours, phlegms, biles and alchemy. Adding mass that can't be seen preserves the body of theory of the standard model and doesn't raise any questions of why GR/QM work correctly for things like GPS etc. In other words, dark matter is an answer that doesn't require going backwards. Saying that gravity behaves differently to what we previously thought means that the standard model is only coincidentally right or only right in particular places, and from there where does the scepticism end? Where do you even start unravelling the tapestry? Think about it in a diagnostic analogy. If your patient is critically ill, and you don't know why, you will prioritise testing for conditions that fit the symptoms and can actually be treated/cured. Because if it isn't treatable, the truth of what caused it isn't that important. Occam's Razor as an argument against dark matter, but saying that gravity behaves differently — when our theories do not otherwise predict that it should behave differently — is actually less simple than saying there is more mass than can be detected via EM interaction. The other point I would make is that dark matter can explain most if not all of the otherwise problematic observations, which makes it preferable over modifying the laws of physics, because as I understand it, doing this doesn't account for all of the problematic observations. Again with an analogy to medicine, it is less likely to be three unrelated, coincidental conditions in one patient than a single condition if both diagnoses explain the same symptoms. To frame everything I've said in a medical analogy, we have essentially treated for the condition we think it is, and we're trying to figure out why the condition has presented differently to typical cases, rather than ruling out the diagnosis and saying it is something else entirely — because the treatment is working. That is, the empirical evidence we have suggests that our diagnosis is correct, but we don't know everything there is to know about the condition. Our GPS works, gravitational lensing has been observed, gravitational waves have been detected, we power our homes with nuclear reactors, we calibrate our most accurate clocks based on quantum mechanics, and so on. Particles we then predicted would exist have since been detected. The patient had a fever. We treated the patient with antibiotics, and they got better, so we have reason to believe it's a bacterial infection — we just can't see the bacteria in the blood work. So the next logical step is to think of what presents and responds like a bacterial infection but isn't bacterial, or otherwise speculate that we have discovered something that does this, rather than question whether we understand the human body or whether thermometers work. If in trying to confirm this discovery, we find that actually we don't really understand the human body or that our instruments are broken, that's when we should start looking to re-assess the laws of physics. The standard model has no useful purpose if we don't place some trust in it to find new things. If we threw out our scientific models every time we encountered something we weren't expecting, we wouldn't make any progress at all. The only reason dark matter raises so many eyebrows is (a) the popular press just loves to pick at it because it's an easy target with great headlining when your scientists are saying the majority of the universe is "missing"; and (b) because the breakthroughs of today are framed as being incremental compared to the big eureka moments of the 19th and 20th centuries which saw us leap from Newtonian mechanics to GR and QM. But between Newton and Einstein et al, there were centuries of incremental refinements/improvements on Newtonian mechanics and early modern astronomy, so why is there such impatience because we haven't found dark matter in barely a hundred years? By definition, dark matter is going to be hard to detect because the only means of detecting it is merely enough to suppose that it exists, i.e. it interacts gravitationally but not electromagnetically, so we can only detect its gravitational influence on celestial bodies. Of course, it's the odd behaviour of celestial bodies that led us to suspect that dark matter was a thing in the first place, so this isn't very helpful. I should think that, in order to prove dark matter exists, we shall have to imagine an edge case of what an extreme concentration of dark matter would do to nearby celestial matter and how that might be distinguished from conventional phenomena. Easier said than done, the universe is full of bizarre phenomena, much of which can be explained by GR and QM, and any remainders probably defy any remotely intuitive reasoning. Alternatively, we shall have to imagine what phenomena might occur in situations where dark matter is absent, and where something can be modelled mathematically as being conclusively due to a lack of dark matter i.e. if gravity were to be different to Newtonian/GR, the phenomenon would never be seen, we can then say with confidence that dark matter is real. To confirm it beyond any useful doubt, I suppose we would need to create conditions under which dark matter would form and observe the phenomena that occur, or build some kind of instrument that can detect gravitationally as accurately as we can detect electromagnetically. Again, easier said than done, EM force has a fundamental particle that we know very well, while gravity ... well the jury's still out on that. The graviton even if it were a thing would not be a particle in the same way, you can't have a quanta of gravity, when gravity is more of an emergent property of the geometry of spacetime? You can do the math as though it has a force carrier, but this isn't something that you expect to be able to manipulate as a particle in application. Anyway, I'm away on a pretty hefty tangent now. The point is that it's more constructive to suppose that there is dark matter, since alternative theories (a) also include dark matter, to a lesser extent and (b) do not account for the observed behaviours without in some ways failing to predict behaviours we know and understand with known physics.
ben_w 3y ago
> no good reason is ever given as to why it could be matter and not anything else The options are 1. matter; 2. energy; 3. new physics. We'd expect pure energy to not stay still for long enough to do anything. Lots of people are looking for new physics, and would be anyway even if it weren't for all the things that made us look for dark matter in the first place, because of the whole "relativity and quantum mechanics don't play well together, and neither is sufficient by itself" problems. Dark matter requires something new, given it can't be explained by baryons or black holes, so it too needs some new physics — though as "matter" it would be in the particles-and-fields area rather than the how-does-spacetime-even area which the not-actually-matter solution would be.
nwallin 3y ago
Dark matter is more complicated than that. It would be nice if it were as simple as you claim it is, but it isn't. From the '30s through to the '70s, evidence was piling up that what we saw and what our models predict were incompatible. Zwicky's application of the virial theorem to a galaxy cluster, and various astronomer's calculations of galaxy rotation curves implied that either there was a bunch of stuff we couldn't see, or general relativity was wrong, or both. MOND was born in this era to explain that general relativity was wrong. (note when I say "wrong" I mean in the same way F = Gmm/r^2 is wrong: it's correct in the limit, but wrong in the extremes. Newtonian gravity is wrong at very high acceleration, and MOND implies General Relativity is wrong at very low acceleration) If science had stopped in 1985, you'd be correct: we couldn't tell the difference between dark matter as particles, (CDM, cold dark matter) dark matter as heavy dark objects, (MACHOs: brown dwarfs, black holes) or dark matter as a new gravity model. (MOND: modified Newtonian dynamics) But science did not stop in 1985. First and most obvious is gravitational lensing and the bullet cluster. This is well trodden ground, so I won't get too much into it: but the bullet cluster shows us that whatever dark matter is, it has momentum. Some MOND theories do predict something like that, and are compatible with the bullet cluster, other models are not compatible with that, and are falsified by the bullet cluster. Second is baryon acoustic oscillations. (BAOs) In the few minutes after the Big Bang, the universe was, to a first approximation, a roiling sea of photons. There were electrons, protons, and the odd helium/lithium nucleus, but because charged particles interact via the electromagnetic force, they were being tossed about on the sea of photons. Baryons could not form overdensities because they were charged, and if anything thought about clumping up, the photons would scatter them. But baryons were not the only objects with mass: there was also dark matter. Dark matter could form clumps, and clumps formed by clumping dark matter would be able to clump normal matter. Eventually, the universe cooled enough that normal matter could clump properly, and at the moment the universe cooled enough to be transparent, the cosmic microwave background (CMB) was born. In order for the CMB to look the way it does, there are very tight bounds on how dark matter has to behave, and wouldn't ya know it, these bounds are compatible with the bounds on CDM in order to explain galaxy clusters and galactic rotation curves. Third is the detection of ultra diffuse galaxies. These galaxies are remnants from a galaxy merger, which spilled off some of its normal matter but none of its dark matter, creating a galaxy with negligible dark matter. In other cases, these collisions create massive blobs of dark matter, but with little to no normal matter. These galaxies falsify MOND. For MOND to be correct, these galaxies cannot exist. Forth is LIGO/VIRGO and the neutron star-neutron star collision a few years ago and the associated gamma ray burst. Many MOND theories predict that gravity travels slower than light. However, GW170817 shows that gravity travels at the speed of light. Some MOND theories are compatible with this, others are not. In general, theories of MOND comes in two flavors: those that are compatible with the bullet cluster, and those that are compatible with GW170817. None of them, AFAIK, are compatible with both. So if you want a MOND theory with no CDM, that's fine, but you have a number of hurdles to jump. You need to create a theoretical framework which is compatible with both the bullet cluster and GW170817, which nobody's been able to do. You need to show that ultra diffuse galaxies are a sensor or interpretation error; those galaxies are significantly closer or farther than currently believed. You need to come up with an entirely new mechanism that explains BAOs. It's not impossible, it is just extraordinarily difficult.

by uoaei 3y ago

JumpCrisscross 3y ago

> no good reason is ever given as to why it could be matter and not anything else Man, astrophysics and finance are not this forum’s strong suit. See the bullet cluster observations [1]. Explain it simultaneously with most galaxy’s spins, but also NGC 1277’s [2], without using dark matter. [1] https://en.m.wikipedia.org/wiki/Bullet_Cluster https://en.m.wikipedia.org/wiki/Bullet_Cluster [2] https://en.m.wikipedia.org/wiki/NGC_1277 https://en.m.wikipedia.org/wiki/NGC_1277

uoaei 3y ago
Far from settled: https://arxiv.org/abs/1003.0939 https://arxiv.org/abs/1003.0939 But armchair physicists love to shriek 'bullet cluster' every time because they aren't aware of the extent of their ignorance. Considering your HN bio I'd comfortably classify you as "knows just enough to be dangerous". Fair, given your generalization knowing nothing about me? More reading for your benefit, from a working astrophysics professor specializing in ultra-diffuse galaxies: https://tritonstation.com/2016/12/23/crater-2-the-bullet-cluster-of-lcdm/ https://tritonstation.com/2016/12/23/crater-2-the-bullet-clu... https://tritonstation.com/2017/03/06/lcdm-has-met-the-enemy-and-it-is-itself/ https://tritonstation.com/2017/03/06/lcdm-has-met-the-enemy-... https://tritonstation.com/2016/07/30/missing-baryons/ https://tritonstation.com/2016/07/30/missing-baryons/
- deleted 3y ago
  [deleted]
- JumpCrisscross 3y ago
  Lots of ground between settled science and “no good reason is ever given.” There are strong arguments for dark matter (broadly, not just Lambda CDM). They are inconclusive. The bullet cluster is less strong evidence for dark matter than good evidence against common armchair refutations. (I agree with your author that it doesn’t rule out MOND as is commonly claimed.)
  - uoaei 3y ago
    The arguments inevitably and only boil down to "look, our model converged". The point is, dark matter is not a theory, just a supposition that can always be "proven" with conveniently arbitrarily flexible models (no one can see it so it might be anywhere!). There is no positive theory that has been brought out to explain dark matter, only mere deductive hypothesis about where it would be. Deduction needs a culprit so people keep reaching for different kinds of particles. Jury's out on whether they exist but keeps the experimentalists employed, so at least it's worth that much.
    - JumpCrisscross 3y ago
      Fair enough. I think it’s qualitatively different from SUSY, where I tend towards your conclusion of jobs programme masquerading as theory. (I’m much less convinced dark matter is a novel particle.)
    - jboy55 3y ago
      There have been actually many positive theories trying to explain what particles dark matter could be, they've all been proven wrong. To me dark matter came about from this, "As we understand gravity we can postulate how galaxies rotate given an estimate on its mass, galaxies do not rotate like this" In this statement there are three elements; 1) Our understanding of gravity 2) Our estimates of the mass of galaxies 3) Our ability to determine how galaxies rotate. At one point in time this last 100 years, we had "solved" gravity with regards to our solar system, and we were finding so many new particles that #2 seemed like a great explanation. However, we are now left with no room in our understanding of particles, I think its time to look at the other elements. Put it this way, if we had never observed the galaxy, but developed the standard model in isolation. Then we looked at the stars and tried to define gravity, I'm not sure we'd be so quick to introduce a new type of matter to define gravity.

wanda 3y ago

The good reason for adding dark matter, that you say is absent, is one that is more a question of philosophy of science, in that adding more mass accounts for the observed behaviours without changing the known laws of physics. The known laws of physics have been formed on math that checks out and is consistent with all our other observations, and has made many predictions that have checked out and even formed the basis for technology that we use every day. The way science works is that we form mathematical models of physical behaviour, we test model against real world data, and if the model is consistent with reality, and predicts further behaviours that we then can test for, the theory behind it holds water and we have something to work from. If you like, you can think of it as building trust in a model, having courage in a theory isn't a mistake, it's how science has been built. Of course finding the errors and new laws is important, but you have to conclusively rule out the established theory first. This is how we got to Newtonian mechanics instead of firmaments, elements, worlds of forms and mythologies, and how we got to medicine instead of humours, phlegms, biles and alchemy. Adding mass that can't be seen preserves the body of theory of the standard model and doesn't raise any questions of why GR/QM work correctly for things like GPS etc. In other words, dark matter is an answer that doesn't require going backwards. Saying that gravity behaves differently to what we previously thought means that the standard model is only coincidentally right or only right in particular places, and from there where does the scepticism end? Where do you even start unravelling the tapestry? Think about it in a diagnostic analogy. If your patient is critically ill, and you don't know why, you will prioritise testing for conditions that fit the symptoms and can actually be treated/cured. Because if it isn't treatable, the truth of what caused it isn't that important. Occam's Razor as an argument against dark matter, but saying that gravity behaves differently — when our theories do not otherwise predict that it should behave differently — is actually less simple than saying there is more mass than can be detected via EM interaction. The other point I would make is that dark matter can explain most if not all of the otherwise problematic observations, which makes it preferable over modifying the laws of physics, because as I understand it, doing this doesn't account for all of the problematic observations. Again with an analogy to medicine, it is less likely to be three unrelated, coincidental conditions in one patient than a single condition if both diagnoses explain the same symptoms. To frame everything I've said in a medical analogy, we have essentially treated for the condition we think it is, and we're trying to figure out why the condition has presented differently to typical cases, rather than ruling out the diagnosis and saying it is something else entirely — because the treatment is working. That is, the empirical evidence we have suggests that our diagnosis is correct, but we don't know everything there is to know about the condition. Our GPS works, gravitational lensing has been observed, gravitational waves have been detected, we power our homes with nuclear reactors, we calibrate our most accurate clocks based on quantum mechanics, and so on. Particles we then predicted would exist have since been detected. The patient had a fever. We treated the patient with antibiotics, and they got better, so we have reason to believe it's a bacterial infection — we just can't see the bacteria in the blood work. So the next logical step is to think of what presents and responds like a bacterial infection but isn't bacterial, or otherwise speculate that we have discovered something that does this, rather than question whether we understand the human body or whether thermometers work. If in trying to confirm this discovery, we find that actually we don't really understand the human body or that our instruments are broken, that's when we should start looking to re-assess the laws of physics. The standard model has no useful purpose if we don't place some trust in it to find new things. If we threw out our scientific models every time we encountered something we weren't expecting, we wouldn't make any progress at all. The only reason dark matter raises so many eyebrows is (a) the popular press just loves to pick at it because it's an easy target with great headlining when your scientists are saying the majority of the universe is "missing"; and (b) because the breakthroughs of today are framed as being incremental compared to the big eureka moments of the 19th and 20th centuries which saw us leap from Newtonian mechanics to GR and QM. But between Newton and Einstein et al, there were centuries of incremental refinements/improvements on Newtonian mechanics and early modern astronomy, so why is there such impatience because we haven't found dark matter in barely a hundred years? By definition, dark matter is going to be hard to detect because the only means of detecting it is merely enough to suppose that it exists, i.e. it interacts gravitationally but not electromagnetically, so we can only detect its gravitational influence on celestial bodies. Of course, it's the odd behaviour of celestial bodies that led us to suspect that dark matter was a thing in the first place, so this isn't very helpful. I should think that, in order to prove dark matter exists, we shall have to imagine an edge case of what an extreme concentration of dark matter would do to nearby celestial matter and how that might be distinguished from conventional phenomena. Easier said than done, the universe is full of bizarre phenomena, much of which can be explained by GR and QM, and any remainders probably defy any remotely intuitive reasoning. Alternatively, we shall have to imagine what phenomena might occur in situations where dark matter is absent, and where something can be modelled mathematically as being conclusively due to a lack of dark matter i.e. if gravity were to be different to Newtonian/GR, the phenomenon would never be seen, we can then say with confidence that dark matter is real. To confirm it beyond any useful doubt, I suppose we would need to create conditions under which dark matter would form and observe the phenomena that occur, or build some kind of instrument that can detect gravitationally as accurately as we can detect electromagnetically. Again, easier said than done, EM force has a fundamental particle that we know very well, while gravity ... well the jury's still out on that. The graviton even if it were a thing would not be a particle in the same way, you can't have a quanta of gravity, when gravity is more of an emergent property of the geometry of spacetime? You can do the math as though it has a force carrier, but this isn't something that you expect to be able to manipulate as a particle in application. Anyway, I'm away on a pretty hefty tangent now. The point is that it's more constructive to suppose that there is dark matter, since alternative theories (a) also include dark matter, to a lesser extent and (b) do not account for the observed behaviours without in some ways failing to predict behaviours we know and understand with known physics.

ben_w 3y ago

> no good reason is ever given as to why it could be matter and not anything else The options are 1. matter; 2. energy; 3. new physics. We'd expect pure energy to not stay still for long enough to do anything. Lots of people are looking for new physics, and would be anyway even if it weren't for all the things that made us look for dark matter in the first place, because of the whole "relativity and quantum mechanics don't play well together, and neither is sufficient by itself" problems. Dark matter requires something new, given it can't be explained by baryons or black holes, so it too needs some new physics — though as "matter" it would be in the particles-and-fields area rather than the how-does-spacetime-even area which the not-actually-matter solution would be.

nwallin 3y ago

Dark matter is more complicated than that. It would be nice if it were as simple as you claim it is, but it isn't. From the '30s through to the '70s, evidence was piling up that what we saw and what our models predict were incompatible. Zwicky's application of the virial theorem to a galaxy cluster, and various astronomer's calculations of galaxy rotation curves implied that either there was a bunch of stuff we couldn't see, or general relativity was wrong, or both. MOND was born in this era to explain that general relativity was wrong. (note when I say "wrong" I mean in the same way F = Gmm/r^2 is wrong: it's correct in the limit, but wrong in the extremes. Newtonian gravity is wrong at very high acceleration, and MOND implies General Relativity is wrong at very low acceleration) If science had stopped in 1985, you'd be correct: we couldn't tell the difference between dark matter as particles, (CDM, cold dark matter) dark matter as heavy dark objects, (MACHOs: brown dwarfs, black holes) or dark matter as a new gravity model. (MOND: modified Newtonian dynamics) But science did not stop in 1985. First and most obvious is gravitational lensing and the bullet cluster. This is well trodden ground, so I won't get too much into it: but the bullet cluster shows us that whatever dark matter is, it has momentum. Some MOND theories do predict something like that, and are compatible with the bullet cluster, other models are not compatible with that, and are falsified by the bullet cluster. Second is baryon acoustic oscillations. (BAOs) In the few minutes after the Big Bang, the universe was, to a first approximation, a roiling sea of photons. There were electrons, protons, and the odd helium/lithium nucleus, but because charged particles interact via the electromagnetic force, they were being tossed about on the sea of photons. Baryons could not form overdensities because they were charged, and if anything thought about clumping up, the photons would scatter them. But baryons were not the only objects with mass: there was also dark matter. Dark matter could form clumps, and clumps formed by clumping dark matter would be able to clump normal matter. Eventually, the universe cooled enough that normal matter could clump properly, and at the moment the universe cooled enough to be transparent, the cosmic microwave background (CMB) was born. In order for the CMB to look the way it does, there are very tight bounds on how dark matter has to behave, and wouldn't ya know it, these bounds are compatible with the bounds on CDM in order to explain galaxy clusters and galactic rotation curves. Third is the detection of ultra diffuse galaxies. These galaxies are remnants from a galaxy merger, which spilled off some of its normal matter but none of its dark matter, creating a galaxy with negligible dark matter. In other cases, these collisions create massive blobs of dark matter, but with little to no normal matter. These galaxies falsify MOND. For MOND to be correct, these galaxies cannot exist. Forth is LIGO/VIRGO and the neutron star-neutron star collision a few years ago and the associated gamma ray burst. Many MOND theories predict that gravity travels slower than light. However, GW170817 shows that gravity travels at the speed of light. Some MOND theories are compatible with this, others are not. In general, theories of MOND comes in two flavors: those that are compatible with the bullet cluster, and those that are compatible with GW170817. None of them, AFAIK, are compatible with both. So if you want a MOND theory with no CDM, that's fine, but you have a number of hurdles to jump. You need to create a theoretical framework which is compatible with both the bullet cluster and GW170817, which nobody's been able to do. You need to show that ultra diffuse galaxies are a sensor or interpretation error; those galaxies are significantly closer or farther than currently believed. You need to come up with an entirely new mechanism that explains BAOs. It's not impossible, it is just extraordinarily difficult.