Dark Matter -

Most evidence suggests dark matter is "cold," meaning its particles move slowly relative to the speed of light. 🔭 Key Evidence

It provides the "glue" that keeps galaxies from flying apart. Dark Matter

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 Most evidence suggests dark matter is "cold," meaning

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