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Context: Factoring in gravitomagnetism could do away with dark matter https://phys.org/news/2021-03-factoring-gravitomagnetism-dark.html https://phys.org/news/

Context: Factoring in gravitomagnetism could do away with dark matter https://phys.org/news/2021-03-factoring-gravitomagnetism-dark.html https://phys.org/news/2021-03-factoring-gravitomagnetism-dar... > Current assessments of galactic rotation curves are based upon a framework of Newtonian accounts of gravity, a new paper published in EPJ C, by Gerson Otto Ludwig, suggests that if this is substituted with a general relativity-based model, the need to recourse to dark matter is relieved, replaced by the effects of gravitomagnetism. > In this paper, Ludwig presents a new model for the rotational curves of galaxies which is in agreement with previous efforts involving general relativity. [...] eliminating the need for dark matter. The theory still needs some development before it is widely accepted, with the author particularly pointing out that the time evolution of galaxies modelled with this framework is a complex problem [...]

jonplackett 6y ago
How long until someone verifies if this is actually right? I’ve never liked dark matter. I hope it doesn’t exist.
- de6u99er 6y ago
  To me Dark Matter was always just another term for Aether, a mysterious something made up to name the unexplainable.
  - irjustin 6y ago
    It is because there needed to be a name for something that was unexplainable.
    - jonplackett 6y ago
      But I didn’t like the way it was named as if it was something specific. ‘Matter’ makes it seem like a specific thing when it was just a made up thing because we didn’t know some other thing. (I like talking in past tense about dark matter) In general I don’t like the way science is taught as if we already know everything. It would be much better to make more of the things we don’t know. That would be a lot more inspiring.
      - ncmncm 6y ago
        This! All progress in science has come from, exactly, attention to what doesn't fit. The next generation will need to work on those things, or see them resolved first, and take on the next level. Now is the time for them to hear about the problems they will face, and develop a thirst for answers.
- JProthero 6y ago
  The author of the article apparently shares your view about dark matter — could you explain what you find objectionable about it? It seems to me that there is a class of concepts in theoretical physics that some people take an almost instinctive dislike to: dark matter, string theory, eternal inflation and the many worlds interpretation of quantum mechanics are prominent ones. I get the impression that there is a correlation; a person who is sceptical about dark matter seems to be much more likely to be sceptical about certain other ideas too, and to have a more favourable view of alternatives like Modified Newtonian Dynamics and Bohmian Mechanics. It's as though there is a sort of partisanship in opinion about theoretical physics: just as it is often possible to tell what somebody's view is likely to be about a whole slew of political issues if you know their opinion about one or two controversial topics, the same seems to apply to a large extent in theoretical physics too. I'm fascinated by this because in the early to mid 2000s I would have counted myself as both a dark matter and many worlds sceptic, but I take the opposite view of both now, and I find it difficult to put myself back into my old frame of mind. My sense is that the divide is somehow related to different attitudes to falsifiability, abstractness and explanatory parsimony.
  - jonplackett 6y ago
    That’s a really interesting observation. Well, the main thing I didn’t like was the labelling of an unknown as if it was a thing that was known. I don’t have anything against the theory, just the way it was named as if it was more certain to exist than it really is.
    - JProthero 6y ago
      Thanks for this; reading your explanation reminds me of the objections I had too.
      - richardw 6y ago
        Put me in that camp too! I know a small text box won’t get across what changed for you but I’d love to know what I’m probably missing. What’s the text box version? For me, it feels like we limit the search because we’ve found a pretty good answer. There’s a fashion and if you aren’t fashionable then you can’t get tenure. We should continue to explore the unfashionable edges. PS I love the idea that it’s similar to clusters of political preferences.
- pizzazzaro 6y ago
  Dark Matter always struck me as the "aether" of the 20th Century.
irjustin 6y ago
Wait is this saying that no one ever applied GRE at galactic scales? That seems absurd, but that's also what the article is saying.
- jonplackett 6y ago
  If it’s true, or even if in this instance it’s not, it makes you wonder how many things there are that someone could just figure out with just the currently available information.
- nimish 6y ago
  Everyone assumed the correct limit was just Newton's gravity, but it's abundantly clear that can't be right what with gravitational waves existing. I think the author's, and other's points over the last decade or so has been "Newton neglects too much in the weak field" and that neglected bit isn't insignificant. The surprise here is that sticking that little bit -- which is needed for gravitational waves and in general the finite speed of gravitation interactions to occur -- appears to eliminate the need for dark matter in galaxy rotation curves. Most surprising is that no one questioned the Newtonian limit being used despite weak field GR and Newton's laws predicting different phenomena. The real test will be if CMB and other precision observations also work w/o dark matter.
- geeB 6y ago
  I think probably most astrophysicists did and realized GR does not matter that much at galactic scales. See my top level comment to this article for an explanation (disclaimer: not a professional physicist, I could very well be wrong).
pontifier 6y ago
Flashback to 8 months ago when I mentioned this idea here: https://news.ycombinator.com/item?id=23673927 https://news.ycombinator.com/item?id=23673927 As it turns out, I'm also working on a fusion device.

jonplackett 6y ago

How long until someone verifies if this is actually right? I’ve never liked dark matter. I hope it doesn’t exist.

de6u99er 6y ago
To me Dark Matter was always just another term for Aether, a mysterious something made up to name the unexplainable.
- irjustin 6y ago
  It is because there needed to be a name for something that was unexplainable.
  - jonplackett 6y ago
    But I didn’t like the way it was named as if it was something specific. ‘Matter’ makes it seem like a specific thing when it was just a made up thing because we didn’t know some other thing. (I like talking in past tense about dark matter) In general I don’t like the way science is taught as if we already know everything. It would be much better to make more of the things we don’t know. That would be a lot more inspiring.
    - ncmncm 6y ago
      This! All progress in science has come from, exactly, attention to what doesn't fit. The next generation will need to work on those things, or see them resolved first, and take on the next level. Now is the time for them to hear about the problems they will face, and develop a thirst for answers.
JProthero 6y ago
The author of the article apparently shares your view about dark matter — could you explain what you find objectionable about it? It seems to me that there is a class of concepts in theoretical physics that some people take an almost instinctive dislike to: dark matter, string theory, eternal inflation and the many worlds interpretation of quantum mechanics are prominent ones. I get the impression that there is a correlation; a person who is sceptical about dark matter seems to be much more likely to be sceptical about certain other ideas too, and to have a more favourable view of alternatives like Modified Newtonian Dynamics and Bohmian Mechanics. It's as though there is a sort of partisanship in opinion about theoretical physics: just as it is often possible to tell what somebody's view is likely to be about a whole slew of political issues if you know their opinion about one or two controversial topics, the same seems to apply to a large extent in theoretical physics too. I'm fascinated by this because in the early to mid 2000s I would have counted myself as both a dark matter and many worlds sceptic, but I take the opposite view of both now, and I find it difficult to put myself back into my old frame of mind. My sense is that the divide is somehow related to different attitudes to falsifiability, abstractness and explanatory parsimony.
- jonplackett 6y ago
  That’s a really interesting observation. Well, the main thing I didn’t like was the labelling of an unknown as if it was a thing that was known. I don’t have anything against the theory, just the way it was named as if it was more certain to exist than it really is.
  - JProthero 6y ago
    Thanks for this; reading your explanation reminds me of the objections I had too.
    - richardw 6y ago
      Put me in that camp too! I know a small text box won’t get across what changed for you but I’d love to know what I’m probably missing. What’s the text box version? For me, it feels like we limit the search because we’ve found a pretty good answer. There’s a fashion and if you aren’t fashionable then you can’t get tenure. We should continue to explore the unfashionable edges. PS I love the idea that it’s similar to clusters of political preferences.
pizzazzaro 6y ago
Dark Matter always struck me as the "aether" of the 20th Century.

irjustin 6y ago

Wait is this saying that no one ever applied GRE at galactic scales? That seems absurd, but that's also what the article is saying.

jonplackett 6y ago
If it’s true, or even if in this instance it’s not, it makes you wonder how many things there are that someone could just figure out with just the currently available information.
nimish 6y ago
Everyone assumed the correct limit was just Newton's gravity, but it's abundantly clear that can't be right what with gravitational waves existing. I think the author's, and other's points over the last decade or so has been "Newton neglects too much in the weak field" and that neglected bit isn't insignificant. The surprise here is that sticking that little bit -- which is needed for gravitational waves and in general the finite speed of gravitation interactions to occur -- appears to eliminate the need for dark matter in galaxy rotation curves. Most surprising is that no one questioned the Newtonian limit being used despite weak field GR and Newton's laws predicting different phenomena. The real test will be if CMB and other precision observations also work w/o dark matter.
geeB 6y ago
I think probably most astrophysicists did and realized GR does not matter that much at galactic scales. See my top level comment to this article for an explanation (disclaimer: not a professional physicist, I could very well be wrong).

pontifier 6y ago

Flashback to 8 months ago when I mentioned this idea here: https://news.ycombinator.com/item?id=23673927 https://news.ycombinator.com/item?id=23673927 As it turns out, I'm also working on a fusion device.