Making Maps of the Cosmos

S1 E3: Discover how astrophysicists map the universe. Focus on the tricky problem of calculating distances, seeing how a collection of overlapping techniques provide a "cosmic distance ladder" that works from nearby planets (by means of radar) to stars and galaxies (using parallax and Cepheid variable stars) to far distant galaxies (by observing a type of supernova with a standard intrinsic brightness).