Is Dark Matter Only the Tip of an Invisible Universe of Unknown Forces?


Dark Matter Dwarf Galaxy


Dark matter is aptly named. It emits no light and interacts with visible matter only via gravity. But dark matter might be only the tip of an invisible universe of unknown forces. This possibility has led to a hunt for “dark photons.” Such photons are analogous to ordinary photons, but they are exchanged among particles of dark matter, and according to some models, they may have mass.