Dark matter found in Milky Way’s core
Most of the material of the universe is dark matter—stuff we can’t see, though we can still feel its gravity. It was discovered in the 1970s when astronomer Vera Rubin showed that stars in the outer regions of spiral galaxies, far from the center, were moving faster than they should be. This suggested there was some sort of unseen mass in a “halo” around the galaxy. But physicists disagree over whether all this dark matter is at the margin or if there is some in a galaxy’s core.