TED-EdDark matter: How does it explain a star's speed? - Don Lincoln
TV-PG
2012 • F79 12. Nov. 2012 10 Min.All the stars in a spiral galaxy rotate around a center -- but to astronomers, the speed that each star travels wasn't making sense. Why didn't stars slow down toward the edges as expected? Don Lincoln explains how a mysterious force called dark matter is (possibly) the answer -- and why the search for an answer matters.