To date, at least 19 galaxies have been discovered that appear to be missing dark matter altogether. What this means, in practice, is that these galaxies are rotating so slowly that no additional matter, beyond their complement of visible baryons, is required to explain their gravitational coherence. Only fast-spinning galaxies need the gravitational attraction of extra matter to hold them together; our traditional understanding of gravity is enough to keep the slow-spinning ones from flying apart.
dark matter
A Substantivalist Explanation of Dark Matter
Abstract: In this article I recommend that substantivalism change its focus from what it has been traditionally—a thinly veiled effort to explain the current standard models of physics—and instead embrace the proper focus of philosophy—explaining reality itself. Exploiting that new perspective, I define a rigorous and testable model of spacetime as a substance, and propose […]