Cosmos: A Space-Time Odyssey: Unafraid of the Dark
June 8, 2014 11:43 PM - Season 1, Episode 13 - Subscribe
Victor Hess discovers cosmic rays, and Fritz Zwicky explains them. Tyson moves on to current questions in cosmology — just what are dark matter (also first proposed by Zwicky) and dark energy? The Voyager spacecraft are discussed, along with Sagan's role in designing the "golden record" they carry, and his suggestion that Voyager 1 take the "Pale Blue Dot" photograph of earth.