Dark matter is a mysterious, theoretical substance that NASA calls “the invisible glue that holds the universe together.” Inside an old gold mine deep in South Dakota’s Black Hills, researchers believe they’re close to moving from theory to proof.
In the 1930s, astronomer Fritz Zwicky hypothesized the existence of dark matter, a theoretical substance that physicists believe accounts for 85 percent of all matter in the universe but has never be… [+4404 chars]