3 ms·

Dark matter does not seem to interact electromagnetically, so that rules out all of chemistry.

shireboy 4y ago
Rules out chemistry that interacts with regular matter, but is it ruled out that there are forces that govern dark matter internally? Dark electromagnetism? Or can we tell from interaction with gravity that dark matter doesn't interact with itself in any way?
- aflag 4y ago
  We are not even sure it exists, so anything is possible. All we know is there something we can’t see or detect in any way, except that it affects on how fast the galaxies spin. But it could be that our models are just wrong.
TechBro8615 4y ago
Is dark matter some tangible "stuff," or is it more of an artifact of gaps in our observation? Why do physicists, when confronted with the lack of observational evidence for the "dark matter" that their models predict, assume that "dark matter must exist?" Couldn't the model be wrong? At what point does the unproven prediction of dark matter call into question the many otherwise proven predictions of the Standard Model? How much of the experimental evidence supporting those predictions has an implicit dependency on the same invalid assumptions leading to the prediction of dark matter? I remember reading an HN comment that described the Standard Model as a sort of legacy codebase with technical debt and strange abstractions to fix earlier errors. That resonates with me, and in fact seems applicable to the entirety of the human epistemological "tech tree." I sometimes wonder, what secrets might we uncover if we could start fresh, speed running different paths through the tech tree?
- shireboy 4y ago
  My (completely unqualified, armchair level) understanding is that most think dark matter is actually real substance that interacts with gravity but not any other force. https://en.wikipedia.org/wiki/Dark_matter#Observational_evidence https://en.wikipedia.org/wiki/Dark_matter#Observational_evid... "Tangible" might be the wrong word since our regular-matter senses and sensors could not "touch" it. Theories do exist that our model of gravity is just wrong at large scales. This falls under Modified Newtonian Dynamics, but has problems that don't match observation: https://en.wikipedia.org/wiki/Modified_Newtonian_dynamics#Outstanding_problems_for_MOND https://en.wikipedia.org/wiki/Modified_Newtonian_dynamics#Ou...

Rules out chemistry that interacts with regular matter, but is it ruled out that there are forces that govern dark matter internally? Dark electromagnetism? Or can we tell from interaction with gravity that dark matter doesn't interact with itself in any way?

aflag 4y ago
We are not even sure it exists, so anything is possible. All we know is there something we can’t see or detect in any way, except that it affects on how fast the galaxies spin. But it could be that our models are just wrong.

TechBro8615 4y ago

Is dark matter some tangible "stuff," or is it more of an artifact of gaps in our observation? Why do physicists, when confronted with the lack of observational evidence for the "dark matter" that their models predict, assume that "dark matter must exist?" Couldn't the model be wrong? At what point does the unproven prediction of dark matter call into question the many otherwise proven predictions of the Standard Model? How much of the experimental evidence supporting those predictions has an implicit dependency on the same invalid assumptions leading to the prediction of dark matter? I remember reading an HN comment that described the Standard Model as a sort of legacy codebase with technical debt and strange abstractions to fix earlier errors. That resonates with me, and in fact seems applicable to the entirety of the human epistemological "tech tree." I sometimes wonder, what secrets might we uncover if we could start fresh, speed running different paths through the tech tree?

shireboy 4y ago
My (completely unqualified, armchair level) understanding is that most think dark matter is actually real substance that interacts with gravity but not any other force. https://en.wikipedia.org/wiki/Dark_matter#Observational_evidence https://en.wikipedia.org/wiki/Dark_matter#Observational_evid... "Tangible" might be the wrong word since our regular-matter senses and sensors could not "touch" it. Theories do exist that our model of gravity is just wrong at large scales. This falls under Modified Newtonian Dynamics, but has problems that don't match observation: https://en.wikipedia.org/wiki/Modified_Newtonian_dynamics#Outstanding_problems_for_MOND https://en.wikipedia.org/wiki/Modified_Newtonian_dynamics#Ou...