My (completely unqualified, armchair level) understanding is that most think dark matter is actually real substance that interacts with gravity but not any othe

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...