Galaxies may be anchored to giant "dark stars" — clumps of invisible matter sitting at their cores, new research suggests.
Although astronomers have an abundance of evidence that most of the mass in any given galaxy is invisible, they do not yet know the identity of this "dark matter." In recent decades, the most promising hypothesis has been that dark matter is made of some kind of heavy particle that rarely, if ever, interacts with light or other matter. But this hypothesis struggles to explain the relatively low densities of galaxy cores, because simulations of dark matter's behavior predict that it should easily clump up to extremely high densities, which does not match observations.
