8 ms·

More bad news for controversial 20-year-old claim of dark matter detection

100 points by furcyd 8y ago

julius_set 8y ago
This does beg the question that what if we as a collective also encounter these sort of defects. For example on a macro scale based on our vantage point from our planet we only have a visible and limited line of sight to specific areas of the galaxy and the visible universe. The same could be same for the atomicverse. What if we are incorrectly making assumptions about things because we don’t see the full picture of how things actually are conceived, embarrassingly so. On the magnitude of way far off.
- saagarjha 8y ago
  > What if we are incorrectly making assumptions about things because we don’t see the full picture of how things actually are conceived, embarrassingly so. This could be true, but I wouldn't call it "embarrassing" to come to flawed conclusions based on inabilities to gather evidence. That's how science works: we do the best with what we have, and continuously try to gather more evidence and refine our theories in response.
  - ab5tract 8y ago
    I think that the scientific community at large is so frightened of the shame of being wrong that they cling to obviously flawed concepts like dark matter (how come I never got to just add in a chunk of invisible theoretical force whenever my equations were unbalanced in school, eh?). The fear of embarrassment is a large part of the inertia against scientific revolutions. Furthermore, men hold an inordinate amount of their masculine confidence in their correctness, further exacerbating their ability to admit to being wrong.
    - m_mueller 8y ago
      If your equations don’t balance because of a lack of a coherent and falsifiable theory for why they don’t, I guess you’ve stumbled across one of the big open questions in science. Which is fine, it just means there’s still white spots on the map. Granted, they’re enormous. Still better than jusf giving up and attributing it to a deity.
      - julius_set 8y ago
        Our own optimism drives us to stay evolutionary fit. Which is great for us. I just wish I could see the full picture one day. It’s mind boggling to think everyone who has lived on this planet died with an incomplete picture and understanding about the true nature of the universe.
        lotis 8y ago
        Okay now get back to work.
      - ab5tract 8y ago
        Who said anything about a deity? My only point is that hubris and embarrassment play a huge role in holding back the evolution of human understanding.
        m_mueller 8y ago
        Nah I didn't intend to accuse you of that, just that science is the successor model to religion as a way to understanding the world. I guess I don't agree about science 'clinging' to dark energy / dark matter - they're basically placeholders until a more coherent theory comes around, and so far that hasn't happened. I don't think a majority of physicists would bat an eye to wave goodbye to those concepts if it became clear how to do it. Now, that's not saying there isn't a whole lot of dogma in science that should be gotten rid of, I even think that the Kopenhagen interpretation has gotten to a dogmatic point - I just don't think that it applies to cosmology. Plenty of influencial astrophycists have open discussions on this, see e.g. R. Penrose.
    - julius_set 8y ago
      It’s not a gender thing. Although, it’s a mental issue —> narcissism, pride, ego. These traits exist in each and everyone to some scale of a degree. But I agree, as someone who used to be super passionate about research. I would say seeing highly regarded individuals fabricate data and assume wrong assumptions, in order to appear respected and important, did dissuade me and me think of the research industry in a different light, one of a business. There are many smart scientists, and they are working hard. The ones that have the resources and means to influence academic papers, experiments and grants are able to influence particular theories and experiments over others. ️ that can lead some theories, your example dark matter is a perfect example to be more accepted than questioned.
    - saagarjha 8y ago
      Nobody seems to have a good idea for what we are dealing with other than we have a mysterious extra "force" show up in our observations, so there's no real "shame" in being wrong here because nobody's gotten it right.
      - ab5tract 8y ago
        Sorry, but when the fundamental equations of your cosmological worldview require elaborate “empty patches” and tons of “oh inventing this would really balance the equations” but you refuse to question the underlying assumptions (gravity as the only organizing force, despite being the weakest one we know), then you are not conducting honest science. And that dishonesty runs rampant through every scientific revolution.
  - julius_set 8y ago
    There are many instances in history of “embarrassingly,”: • The theory that the earth is not the center of the universe - people persecuted sometimes killed for different assumptions. • Spontaneous generation, the idea that life just arises out of nothing, at the time period this was accepted and other ideas disregarded which led to many lives lost due to disease. • Mental illness assumptions in the past led people to view people with mental illness as possessed by demons, etc. leading to cruel and unusual confinement for these individuals • Lots of other examples I would also propose that when observing our primate ape cousins even the smartest monkey to us appears to be “embarrassingly” putting together a coherent picture of actual reality. Then that proposes an interesting thought experiment. If we encountered an alien species with as much intellectual distance from us as we are to the monkeys, then how would our most innovative theories fare against theirs? I would imagine we would be seen as “embarrassingly,” able to put even a fraction of the puzzle together. We have our senses, and therefore we design our materials and probes to match our senses. Sometimes we can imagine high dimensionality in say the form of a tensor? Sure. Maybe we don’t have a complete picture so we build and optimize tools only related to our own sense processing. What if there are more than our senses, and we are incapable of seeing a deeper image of reality? What if have the senses of a snail as a comparison to an even more advanced species.
    - saagarjha 8y ago
      None of those examples you mentioned had a lack of evidence, which is why we changed our perspective on how those things worked. The opposition to them was not scientific.
    - incelmods 8y ago
      this is about science. scientists, by today's definition of the term, were enemies of the church (and still are). other scientists did not burn anyone for saying the earth rotates around the sun, they did not put nails in demented people's heads because "demons," nor did they implement any of the other examples you are thinking of. the rest of your comment is based on the wrong assumption of your start, hence there is no embarrassment for earlier works. Newton was not embarrassed by quantum mechanics.
    - 8y ago
- deleted 8y ago
  [deleted]
- Pharmakon 8y ago
  From Lou Cixin’s ‘The Three-Body Problem’ the “Shooter and Farmer” metaphor seems relevant here. “In the shooter hypothesis, a good marksman shoots at a target, creating a hole every ten centimeters. Now suppose the surface of the target is inhabited by intelligent, two-dimensional creatures. Their scientists, after observing the universe, discover a great law: “There exists a hole in the universe every ten centimeters.” They have mistaken the result of the marksman’s momentary whim for an unalterable law of the universe. The farmer hypothesis, on the other hand, has the flavor of a horror story: Every morning on a turkey farm, the farmer comes to feed the turkeys. A scientist turkey, having observed this pattern to hold without change for almost a year, makes the following discovery: “Every morning at eleven, food arrives.” On the morning of Thanksgiving, the scientist announces this law to the other turkeys. But that morning at eleven, food doesn’t arrive; instead, the farmer comes and kills the entire flock.” A counterpoint to such an observation is that ideally, scientists understand that they’re working with imperfect and incomplete information. It’s still hard to see the universe from a perspective you don’t inhabit though.
perseusprime11 8y ago
IMO, nothing is certain until we arrive at the boundary of universe creation/expansion. This is where all of the real stuff is taking place. Until then, it will be mostly theories and opinions.
- ziont 8y ago
  but how can you put a start and finish to something that is eternal and infinite? god knows how many iteration of terrestrial universes we have gone through already. alls I'm saying is we ask these questions like asking Google and expect clear cut answers when reality itself is uncertain, until it is observed.
- brianberns 8y ago
  There’s no boundary. If you live on the surface of an expanding balloon, where’s the boundary of expansion/creation? There isn’t one. It’s expanding uniformly at every point.
- squirrelicus 8y ago
  Conflating theory and opinion is a bad category error. You're going to have to learn to accept that nothing outside the realm of mathematical proof is certain. Not even Cell Theory is certain.
Domark 8y ago
Finally we can put to rest this dark matter conspiracy. It’s funny how many supported the idea. Science by mob rule huh? Now we have a great example of how scientists are ignorant. Like blaming climate change for unusual weather. Give it a rest, climate change is a ruse.
Damark 8y ago
Finally we can put to rest this dark matter conspiracy. It’s funny how many supported the idea. Science by mob rule huh? Now we have a great example of how scientists are ignorant. Like blaming climate change for unusual weather. Give it a rest, climate change is a ruse.
Diemark 8y ago
Finally we can put to rest this dark matter conspiracy. It’s funny how many supported the idea. Science by mob rule huh? Now we have a great example of how scientists are ignorant. Like blaming climate change for unusual weather. Give it a rest, climate change is a ruse.
- jobigoud 8y ago
  You have not read the article or you have not understood it. For your interest, the article is about how a specific explanation to dark matter is put into question, not whether dark matter exists or not. If you want to discard dark matter you have to propose a better model of physics that also matches all our observations.
  - krapp 8y ago
    The poster you're referring to is a troll account which already has several dead comments with almost the same content. Don't engage with them, especially in a thread like this, where they tend to come out of the woodwork. Flag and move on.
ziont 8y ago
what is dark matter? is it the opposite of matter? how can it be called matter when it doesn't exist? or are these objects from higher dimensions as Michio Kaku postulates? that galaxies are essentially in a bubble of dark matter preventing it from hurling in every direction. as well as the presence of dark matter in orbits, could it not be the space-time curvature from the mass itself but from the encapsulating dark matter around it? I no very little of this subject so I can only ponder and fantasize.
- krapp 8y ago
  Via Wikipedia[0] Dark matter is a hypothetical form of matter that is thought to account for approximately 85% of the matter in the universe, and about a quarter of its total energy density. (...) Its presence is implied in a variety of astrophysical observations, including gravitational effects that cannot be explained unless more matter is present than can be seen. Also, since it will inevitably come up as it always does in threads about dark matter or dark energy , here is an article[1] and related[2] HN thread arguing the theoretical justifications behind the existence of dark matter, what is known or can be inferred about its properties and why chances are no one missed whatever simple solution you can think of, like "maybe it's just normal matter but they can't see it because it's far away" or "maybe it's just black holes" and why it's also not entirely hubris or ignorance on the part of the scientific community. [0]https://en.wikipedia.org/wiki/Dark_matter https://en.wikipedia.org/wiki/Dark_matter [1]https://medium.com/starts-with-a-bang/this-is-the-real-reason-we-havent-directly-detected-dark-matter-3d04021b314e https://medium.com/starts-with-a-bang/this-is-the-real-reaso... [2]https://news.ycombinator.com/item?id=18207276 https://news.ycombinator.com/item?id=18207276
  - rjf72 8y ago
    The article you link there does not mention the SISSA discovery of 2016 [1]. In particular in mini-spiral galaxies there seems to be an unexpected, and inexplicable, interaction between dark and visible matter. This falsifies the primary prediction put forth in that medium article. And in general this issue is one that poses a critical problem for dark matter largely because it cannot just be massaged into the model. And that last point is really the problem with model based physics. They are really really hard to falsify which can provide certainty through inertia. For instance take the heliocentric vs geocentric earth. The geocentric view (that the Earth was the center upon which everything rotated) was based upon a model. It started out fairly simple and intuitive. But then we kept coming upon ever more issues. For instance if everything else rotates around Earth then that must mean other planets travel in sort of 'swirly' type patterns that we see nowhere else in physics. Well, okay - why not. Hmm it also turns out that some planets, such as Mercury, need to just magically stop in their orbit and start going backwards at some point. Again, it's a model that we can't really falsify so okay - why not. And it absorbs really bizarre observation after another. The only way to refute it was ultimately to be able to see 'through the eyes of god' that geocentricism was wrong. This was not hubris or ignorance on part of the scientific community. It was inertia. Hundreds of years scientific study was built upon the assumption of a geocentric Earth. Astrology was a scholarly pursuit, at least as reputable as psychology is today, developed over centuries. And it was 100% dependent upon the geocentric model. We've rewritten history to blame geocentricism on the church alone, but there was far more in play there. Going against the geocentric model meant having the arrogance to call numerous well reputed fields completely wrong, to completely discredit and repudiate the work of the most brilliant minds of the times, and to basically say you somehow know better than hundreds of years of work and pretty much everybody else. No, it's certainly not hubris that drives inertia. It's the lack thereof. Einstein's theory of relativity sounds absolutely insane. It took the sort of man who would go on to condescendingly mock quantum entanglement as "spooky action at a distance" to have the sort of ego and self confidence, bordering on hubris, to be able to not only consider such possibilities but to spend years of countless effort refining and developing it. Much of this done when he, unable to find a professorial position, was working in a patent office - no less! Indeed if we have any bias in play, I'd expect it's rather a contagion of humility driven by the exponential growth in complexity. If anything, the arrogance would come in the form of an aggressive disregard for alternatives. See the practically militant response to things such as MOND [2] hypotheses. It still suffers many problems, as does dark matter, but remains a viable alternative hypothesis which remains rather unexplored. Of course there is a practical issue there. Since nobody expects things such as MOND to be correct, which it probably is not, then spending years proving that is effectively wasted. By contrast as most people expect dark matter to be correct, proving it right or wrong would be an achievement worthy of a trip to Stockholm. It means pursuing MOND (or other alternatives) is a very difficult choice, in terms of career progression and prospects. Scientific inertia is a problem with no clear solution. [1] - https://phys.org/news/2016-12-unexpected-interaction-dark-ordinary-mini-spiral.html https://phys.org/news/2016-12-unexpected-interaction-dark-or... [2] - https://en.wikipedia.org/wiki/Modified_Newtonian_dynamics https://en.wikipedia.org/wiki/Modified_Newtonian_dynamics
deleted 8y ago
[deleted]
ccvannorman 8y ago
Why is every single comment here being downvoted? I think many of them raise valid points and discussions; I, too, have always been suspicious of "dark matter" and have always looked at other possible explanations, such as "it appears there is matter/gravity there from our vantage point, but with a broader perspective/more complete picture we might see that { space time curves differently at the local, galaxy, intergalaxy scale (for example)}".
- magicalhippo 8y ago
  You make it sound like physicists haven't tried looking for alternative explanations. Faced with our many, varied observations there are two choices: either general relativity is wrong at larger scales, or there's some stuff out there that doesn't interact with light or much of anything else. Maybe it's a combination of both, but to begin with it's usually a good idea assume the simpler alternative that it's just one of them. Some physicists are looking at changing general relativity. MOND[1] is just a modification of Newton's law, so while it does reproduce the galaxy rotation curve observations it doesn't really explain anything in the same way GR does, and it's also non-relativistic which is pretty much a showstopper. There are efforts to make a relativistic MOND-like theory, such as TeVeS[2], but so far nothing has stood up. Some have considered that maybe quantum gravitational effects[3] reproduce the dark matter observations, but that approach also seem to have problems. Your example implies a modification of GR. It appears to be very difficult to modify GR at large scales while conforming to all the observations which validate plain GR. So a good alternative guess is that there's something matter-like out there we can't see. Doing so, physicists have considered MACHOs[4], and they're currently searching for WIMPs[5], sterile neutrinos[6] and axions[7] to name a few candidate particles. If some new theory comes along which supersedes GR, explains all the things plain GR can while also explaining the dark matter observations, then it would be welcomed and embraced by the physics community. Until then, physicists are looking in the direction they feel is the most promising one. [1]: https://en.wikipedia.org/wiki/Modified_Newtonian_dynamics https://en.wikipedia.org/wiki/Modified_Newtonian_dynamics [2]: https://en.wikipedia.org/wiki/Tensor%E2%80%93vector%E2%80%93scalar_gravity https://en.wikipedia.org/wiki/Tensor%E2%80%93vector%E2%80%93... [3]: https://en.wikipedia.org/wiki/Entropic_gravity https://en.wikipedia.org/wiki/Entropic_gravity [4]: https://en.wikipedia.org/wiki/Massive_compact_halo_object https://en.wikipedia.org/wiki/Massive_compact_halo_object [5]: https://en.wikipedia.org/wiki/Weakly_interacting_massive_particles https://en.wikipedia.org/wiki/Weakly_interacting_massive_par... [6]: https://en.wikipedia.org/wiki/Sterile_neutrino https://en.wikipedia.org/wiki/Sterile_neutrino [7]: https://en.wikipedia.org/wiki/Axion https://en.wikipedia.org/wiki/Axion

100 points by furcyd 8y ago

This does beg the question that what if we as a collective also encounter these sort of defects. For example on a macro scale based on our vantage point from our planet we only have a visible and limited line of sight to specific areas of the galaxy and the visible universe. The same could be same for the atomicverse. What if we are incorrectly making assumptions about things because we don’t see the full picture of how things actually are conceived, embarrassingly so. On the magnitude of way far off.

saagarjha 8y ago
> What if we are incorrectly making assumptions about things because we don’t see the full picture of how things actually are conceived, embarrassingly so. This could be true, but I wouldn't call it "embarrassing" to come to flawed conclusions based on inabilities to gather evidence. That's how science works: we do the best with what we have, and continuously try to gather more evidence and refine our theories in response.
- ab5tract 8y ago
  I think that the scientific community at large is so frightened of the shame of being wrong that they cling to obviously flawed concepts like dark matter (how come I never got to just add in a chunk of invisible theoretical force whenever my equations were unbalanced in school, eh?). The fear of embarrassment is a large part of the inertia against scientific revolutions. Furthermore, men hold an inordinate amount of their masculine confidence in their correctness, further exacerbating their ability to admit to being wrong.
  - m_mueller 8y ago
    If your equations don’t balance because of a lack of a coherent and falsifiable theory for why they don’t, I guess you’ve stumbled across one of the big open questions in science. Which is fine, it just means there’s still white spots on the map. Granted, they’re enormous. Still better than jusf giving up and attributing it to a deity.
    - julius_set 8y ago
      Our own optimism drives us to stay evolutionary fit. Which is great for us. I just wish I could see the full picture one day. It’s mind boggling to think everyone who has lived on this planet died with an incomplete picture and understanding about the true nature of the universe.
      - lotis 8y ago
        Okay now get back to work.
    - ab5tract 8y ago
      Who said anything about a deity? My only point is that hubris and embarrassment play a huge role in holding back the evolution of human understanding.
      - m_mueller 8y ago
        Nah I didn't intend to accuse you of that, just that science is the successor model to religion as a way to understanding the world. I guess I don't agree about science 'clinging' to dark energy / dark matter - they're basically placeholders until a more coherent theory comes around, and so far that hasn't happened. I don't think a majority of physicists would bat an eye to wave goodbye to those concepts if it became clear how to do it. Now, that's not saying there isn't a whole lot of dogma in science that should be gotten rid of, I even think that the Kopenhagen interpretation has gotten to a dogmatic point - I just don't think that it applies to cosmology. Plenty of influencial astrophycists have open discussions on this, see e.g. R. Penrose.
  - julius_set 8y ago
    It’s not a gender thing. Although, it’s a mental issue —> narcissism, pride, ego. These traits exist in each and everyone to some scale of a degree. But I agree, as someone who used to be super passionate about research. I would say seeing highly regarded individuals fabricate data and assume wrong assumptions, in order to appear respected and important, did dissuade me and me think of the research industry in a different light, one of a business. There are many smart scientists, and they are working hard. The ones that have the resources and means to influence academic papers, experiments and grants are able to influence particular theories and experiments over others. ️ that can lead some theories, your example dark matter is a perfect example to be more accepted than questioned.
  - saagarjha 8y ago
    Nobody seems to have a good idea for what we are dealing with other than we have a mysterious extra "force" show up in our observations, so there's no real "shame" in being wrong here because nobody's gotten it right.
    - ab5tract 8y ago
      Sorry, but when the fundamental equations of your cosmological worldview require elaborate “empty patches” and tons of “oh inventing this would really balance the equations” but you refuse to question the underlying assumptions (gravity as the only organizing force, despite being the weakest one we know), then you are not conducting honest science. And that dishonesty runs rampant through every scientific revolution.
- julius_set 8y ago
  There are many instances in history of “embarrassingly,”: • The theory that the earth is not the center of the universe - people persecuted sometimes killed for different assumptions. • Spontaneous generation, the idea that life just arises out of nothing, at the time period this was accepted and other ideas disregarded which led to many lives lost due to disease. • Mental illness assumptions in the past led people to view people with mental illness as possessed by demons, etc. leading to cruel and unusual confinement for these individuals • Lots of other examples I would also propose that when observing our primate ape cousins even the smartest monkey to us appears to be “embarrassingly” putting together a coherent picture of actual reality. Then that proposes an interesting thought experiment. If we encountered an alien species with as much intellectual distance from us as we are to the monkeys, then how would our most innovative theories fare against theirs? I would imagine we would be seen as “embarrassingly,” able to put even a fraction of the puzzle together. We have our senses, and therefore we design our materials and probes to match our senses. Sometimes we can imagine high dimensionality in say the form of a tensor? Sure. Maybe we don’t have a complete picture so we build and optimize tools only related to our own sense processing. What if there are more than our senses, and we are incapable of seeing a deeper image of reality? What if have the senses of a snail as a comparison to an even more advanced species.
  - saagarjha 8y ago
    None of those examples you mentioned had a lack of evidence, which is why we changed our perspective on how those things worked. The opposition to them was not scientific.
  - incelmods 8y ago
    this is about science. scientists, by today's definition of the term, were enemies of the church (and still are). other scientists did not burn anyone for saying the earth rotates around the sun, they did not put nails in demented people's heads because "demons," nor did they implement any of the other examples you are thinking of. the rest of your comment is based on the wrong assumption of your start, hence there is no embarrassment for earlier works. Newton was not embarrassed by quantum mechanics.
  - 8y ago
deleted 8y ago
[deleted]
Pharmakon 8y ago
From Lou Cixin’s ‘The Three-Body Problem’ the “Shooter and Farmer” metaphor seems relevant here. “In the shooter hypothesis, a good marksman shoots at a target, creating a hole every ten centimeters. Now suppose the surface of the target is inhabited by intelligent, two-dimensional creatures. Their scientists, after observing the universe, discover a great law: “There exists a hole in the universe every ten centimeters.” They have mistaken the result of the marksman’s momentary whim for an unalterable law of the universe. The farmer hypothesis, on the other hand, has the flavor of a horror story: Every morning on a turkey farm, the farmer comes to feed the turkeys. A scientist turkey, having observed this pattern to hold without change for almost a year, makes the following discovery: “Every morning at eleven, food arrives.” On the morning of Thanksgiving, the scientist announces this law to the other turkeys. But that morning at eleven, food doesn’t arrive; instead, the farmer comes and kills the entire flock.” A counterpoint to such an observation is that ideally, scientists understand that they’re working with imperfect and incomplete information. It’s still hard to see the universe from a perspective you don’t inhabit though.

perseusprime11 8y ago

IMO, nothing is certain until we arrive at the boundary of universe creation/expansion. This is where all of the real stuff is taking place. Until then, it will be mostly theories and opinions.

ziont 8y ago
but how can you put a start and finish to something that is eternal and infinite? god knows how many iteration of terrestrial universes we have gone through already. alls I'm saying is we ask these questions like asking Google and expect clear cut answers when reality itself is uncertain, until it is observed.
brianberns 8y ago
There’s no boundary. If you live on the surface of an expanding balloon, where’s the boundary of expansion/creation? There isn’t one. It’s expanding uniformly at every point.
squirrelicus 8y ago
Conflating theory and opinion is a bad category error. You're going to have to learn to accept that nothing outside the realm of mathematical proof is certain. Not even Cell Theory is certain.

Domark 8y ago

Finally we can put to rest this dark matter conspiracy. It’s funny how many supported the idea. Science by mob rule huh? Now we have a great example of how scientists are ignorant. Like blaming climate change for unusual weather. Give it a rest, climate change is a ruse.

Damark 8y ago

Diemark 8y ago

jobigoud 8y ago
You have not read the article or you have not understood it. For your interest, the article is about how a specific explanation to dark matter is put into question, not whether dark matter exists or not. If you want to discard dark matter you have to propose a better model of physics that also matches all our observations.
- krapp 8y ago
  The poster you're referring to is a troll account which already has several dead comments with almost the same content. Don't engage with them, especially in a thread like this, where they tend to come out of the woodwork. Flag and move on.

ziont 8y ago

what is dark matter? is it the opposite of matter? how can it be called matter when it doesn't exist? or are these objects from higher dimensions as Michio Kaku postulates? that galaxies are essentially in a bubble of dark matter preventing it from hurling in every direction. as well as the presence of dark matter in orbits, could it not be the space-time curvature from the mass itself but from the encapsulating dark matter around it? I no very little of this subject so I can only ponder and fantasize.

krapp 8y ago
Via Wikipedia[0] Dark matter is a hypothetical form of matter that is thought to account for approximately 85% of the matter in the universe, and about a quarter of its total energy density. (...) Its presence is implied in a variety of astrophysical observations, including gravitational effects that cannot be explained unless more matter is present than can be seen. Also, since it will inevitably come up as it always does in threads about dark matter or dark energy , here is an article[1] and related[2] HN thread arguing the theoretical justifications behind the existence of dark matter, what is known or can be inferred about its properties and why chances are no one missed whatever simple solution you can think of, like "maybe it's just normal matter but they can't see it because it's far away" or "maybe it's just black holes" and why it's also not entirely hubris or ignorance on the part of the scientific community. [0]https://en.wikipedia.org/wiki/Dark_matter https://en.wikipedia.org/wiki/Dark_matter [1]https://medium.com/starts-with-a-bang/this-is-the-real-reason-we-havent-directly-detected-dark-matter-3d04021b314e https://medium.com/starts-with-a-bang/this-is-the-real-reaso... [2]https://news.ycombinator.com/item?id=18207276 https://news.ycombinator.com/item?id=18207276
- rjf72 8y ago
  The article you link there does not mention the SISSA discovery of 2016 [1]. In particular in mini-spiral galaxies there seems to be an unexpected, and inexplicable, interaction between dark and visible matter. This falsifies the primary prediction put forth in that medium article. And in general this issue is one that poses a critical problem for dark matter largely because it cannot just be massaged into the model. And that last point is really the problem with model based physics. They are really really hard to falsify which can provide certainty through inertia. For instance take the heliocentric vs geocentric earth. The geocentric view (that the Earth was the center upon which everything rotated) was based upon a model. It started out fairly simple and intuitive. But then we kept coming upon ever more issues. For instance if everything else rotates around Earth then that must mean other planets travel in sort of 'swirly' type patterns that we see nowhere else in physics. Well, okay - why not. Hmm it also turns out that some planets, such as Mercury, need to just magically stop in their orbit and start going backwards at some point. Again, it's a model that we can't really falsify so okay - why not. And it absorbs really bizarre observation after another. The only way to refute it was ultimately to be able to see 'through the eyes of god' that geocentricism was wrong. This was not hubris or ignorance on part of the scientific community. It was inertia. Hundreds of years scientific study was built upon the assumption of a geocentric Earth. Astrology was a scholarly pursuit, at least as reputable as psychology is today, developed over centuries. And it was 100% dependent upon the geocentric model. We've rewritten history to blame geocentricism on the church alone, but there was far more in play there. Going against the geocentric model meant having the arrogance to call numerous well reputed fields completely wrong, to completely discredit and repudiate the work of the most brilliant minds of the times, and to basically say you somehow know better than hundreds of years of work and pretty much everybody else. No, it's certainly not hubris that drives inertia. It's the lack thereof. Einstein's theory of relativity sounds absolutely insane. It took the sort of man who would go on to condescendingly mock quantum entanglement as "spooky action at a distance" to have the sort of ego and self confidence, bordering on hubris, to be able to not only consider such possibilities but to spend years of countless effort refining and developing it. Much of this done when he, unable to find a professorial position, was working in a patent office - no less! Indeed if we have any bias in play, I'd expect it's rather a contagion of humility driven by the exponential growth in complexity. If anything, the arrogance would come in the form of an aggressive disregard for alternatives. See the practically militant response to things such as MOND [2] hypotheses. It still suffers many problems, as does dark matter, but remains a viable alternative hypothesis which remains rather unexplored. Of course there is a practical issue there. Since nobody expects things such as MOND to be correct, which it probably is not, then spending years proving that is effectively wasted. By contrast as most people expect dark matter to be correct, proving it right or wrong would be an achievement worthy of a trip to Stockholm. It means pursuing MOND (or other alternatives) is a very difficult choice, in terms of career progression and prospects. Scientific inertia is a problem with no clear solution. [1] - https://phys.org/news/2016-12-unexpected-interaction-dark-ordinary-mini-spiral.html https://phys.org/news/2016-12-unexpected-interaction-dark-or... [2] - https://en.wikipedia.org/wiki/Modified_Newtonian_dynamics https://en.wikipedia.org/wiki/Modified_Newtonian_dynamics

deleted 8y ago

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ccvannorman 8y ago

Why is every single comment here being downvoted? I think many of them raise valid points and discussions; I, too, have always been suspicious of "dark matter" and have always looked at other possible explanations, such as "it appears there is matter/gravity there from our vantage point, but with a broader perspective/more complete picture we might see that { space time curves differently at the local, galaxy, intergalaxy scale (for example)}".

magicalhippo 8y ago
You make it sound like physicists haven't tried looking for alternative explanations. Faced with our many, varied observations there are two choices: either general relativity is wrong at larger scales, or there's some stuff out there that doesn't interact with light or much of anything else. Maybe it's a combination of both, but to begin with it's usually a good idea assume the simpler alternative that it's just one of them. Some physicists are looking at changing general relativity. MOND[1] is just a modification of Newton's law, so while it does reproduce the galaxy rotation curve observations it doesn't really explain anything in the same way GR does, and it's also non-relativistic which is pretty much a showstopper. There are efforts to make a relativistic MOND-like theory, such as TeVeS[2], but so far nothing has stood up. Some have considered that maybe quantum gravitational effects[3] reproduce the dark matter observations, but that approach also seem to have problems. Your example implies a modification of GR. It appears to be very difficult to modify GR at large scales while conforming to all the observations which validate plain GR. So a good alternative guess is that there's something matter-like out there we can't see. Doing so, physicists have considered MACHOs[4], and they're currently searching for WIMPs[5], sterile neutrinos[6] and axions[7] to name a few candidate particles. If some new theory comes along which supersedes GR, explains all the things plain GR can while also explaining the dark matter observations, then it would be welcomed and embraced by the physics community. Until then, physicists are looking in the direction they feel is the most promising one. [1]: https://en.wikipedia.org/wiki/Modified_Newtonian_dynamics https://en.wikipedia.org/wiki/Modified_Newtonian_dynamics [2]: https://en.wikipedia.org/wiki/Tensor%E2%80%93vector%E2%80%93scalar_gravity https://en.wikipedia.org/wiki/Tensor%E2%80%93vector%E2%80%93... [3]: https://en.wikipedia.org/wiki/Entropic_gravity https://en.wikipedia.org/wiki/Entropic_gravity [4]: https://en.wikipedia.org/wiki/Massive_compact_halo_object https://en.wikipedia.org/wiki/Massive_compact_halo_object [5]: https://en.wikipedia.org/wiki/Weakly_interacting_massive_particles https://en.wikipedia.org/wiki/Weakly_interacting_massive_par... [6]: https://en.wikipedia.org/wiki/Sterile_neutrino https://en.wikipedia.org/wiki/Sterile_neutrino [7]: https://en.wikipedia.org/wiki/Axion https://en.wikipedia.org/wiki/Axion