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Aren’t the first and third the same thing - we didn’t measure it all? To just invent something that can’t be explained to make us feel better sounds a whole lo

by DougN7 7y ago

Aren’t the first and third the same thing - we didn’t measure it all? To just invent something that can’t be explained to make us feel better sounds a whole lot like religion. [edit] Also, thank you for your reply. It helps

AnimalMuppet 7y ago
One is, either we didn't correctly measure the mass (which we measure by the light emitted), or we didn't measure the rotational velocity correctly (which we measure by doppler differences between the different sides of the galaxy). The third is that there is mass that doesn't emit light at all. (I think it's a bit stronger than that. I think that they think that it doesn't interact with light at all, not just not emit it. But I forget how they think they know that, and I'm not certain that they think they know it at all.) > To just invent something that can’t be explained to make us feel better sounds a whole lot like religion. They don't invent it to make themselves feel better. They invent it so their equations work. (Of course, they feel better when their equations work...)
- dogma1138 7y ago
  Dark matter doesn’t interact with any of the forces other than gravity and possibly the weak force. Not interacting with the electromagnetic force is the same thing as not emitting light. But this also means that DM cannot be cold baryonic matter. MOND or any other modifications of Newtonian Gravity or GR aren’t random. In the case of MOND (and TEVES) Gravity is modified but it’s modified in a manner that is consistent with both macro and micro observations it’s not adding a random dice throw. The reason why people went after MOND and the rest is that Newtonian Gravity is surprisingly accurate even without using PPN. Now the big problem with MOND and most of the other modifications is the speed of gravitational waves that pretty much shut down much of the discussion. That said I’m not entirely sure they had the wrong idea at this point I think it’s more likely we don’t understand something about gravity or space time than there is a new class of matter out there. That said the fact that we have both found clusters which apparently more dark matter than usual and those which seem to completely lack DM is still a good reason to continue searching for DM. However I really don’t like how MOND proponents were treated especially pre-LIGO.

by DougN7 7y ago

AnimalMuppet 7y ago

One is, either we didn't correctly measure the mass (which we measure by the light emitted), or we didn't measure the rotational velocity correctly (which we measure by doppler differences between the different sides of the galaxy). The third is that there is mass that doesn't emit light at all. (I think it's a bit stronger than that. I think that they think that it doesn't interact with light at all, not just not emit it. But I forget how they think they know that, and I'm not certain that they think they know it at all.) > To just invent something that can’t be explained to make us feel better sounds a whole lot like religion. They don't invent it to make themselves feel better. They invent it so their equations work. (Of course, they feel better when their equations work...)

dogma1138 7y ago
Dark matter doesn’t interact with any of the forces other than gravity and possibly the weak force. Not interacting with the electromagnetic force is the same thing as not emitting light. But this also means that DM cannot be cold baryonic matter. MOND or any other modifications of Newtonian Gravity or GR aren’t random. In the case of MOND (and TEVES) Gravity is modified but it’s modified in a manner that is consistent with both macro and micro observations it’s not adding a random dice throw. The reason why people went after MOND and the rest is that Newtonian Gravity is surprisingly accurate even without using PPN. Now the big problem with MOND and most of the other modifications is the speed of gravitational waves that pretty much shut down much of the discussion. That said I’m not entirely sure they had the wrong idea at this point I think it’s more likely we don’t understand something about gravity or space time than there is a new class of matter out there. That said the fact that we have both found clusters which apparently more dark matter than usual and those which seem to completely lack DM is still a good reason to continue searching for DM. However I really don’t like how MOND proponents were treated especially pre-LIGO.