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Dark matter: How does it explain a star's speed? - Don Lincoln

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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.

Dark matter appears to be about five times more common than the familiar form of matter that makes up you and me. When dark energy (which is another component of the universe) is taken into consideration, our regular form of matter comprises a mere 5% of energy and matter in the universe. How do you feel about so much of the universe being composed of matter that we have never directly observed?

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TED-Ed Animations feature the words and ideas of educators brought to life by professional animators. Are you an educator or animator interested in creating a TED-Ed Animation? Nominate yourself here »

Meet The Creators

  • Educator Don Lincoln
  • Director Gatze Zonneveld
  • Narrator Don Lincoln

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