To build on peer replies: the leading dark matter theories from a particle physics perspective imply "particles which do not feel electromagnetism." This ought

To build on peer replies: the leading dark matter theories from a particle physics perspective imply "particles which do not feel electromagnetism." This ought not to be weird! After all, some particles do not feel the strong force (leptons) and others do not feel the weak force (right-handed); why should every particle feel EM? It feels weird because almost everything we see is EM in nature: chemistry, electricity, light, life itself! But there is no a priori reason to demand that everything in the universe interacts through EM. There ought to be some stuff that does not. And if it were to exist, it would be like a ghost: particles which could not shed energy through emitting photons. And the cosmological perspective is that "there's a lot of this stuff, huge amounts" and why not?