Dark Matter (BEST)

In the 1970s, astronomer Vera Rubin observed that stars at the edges of spiral galaxies were moving just as fast as those near the center. According to Newtonian physics, they should have been moving much slower or flying off into space unless some unseen mass was holding them in place. Galaxy Clusters

It does not interact with electromagnetic forces, meaning it is completely transparent. Dark Matter

Dark matter makes up roughly , dwarfing the "ordinary" matter—stars, planets, and people—which accounts for less than 5%. In the 1970s, astronomer Vera Rubin observed that