Transcript: Astronomers at Caltech became interested in the newly accurate radio positions of strong sources in the sky. They focused in particular on two sources, 3C48 and 3C273 which appeared to be associated with bluish stars. Since normal stars like the Sun do not emit strong radio waves this was a mystery. The mystery deepened when Martin Schmidt used the Palomar 200-inch to take spectra of the two stellar counterparts. He saw a series of strong broad lines that he could not identify with any known element. Weeks later, playing with their spectrum, he made the remarkable discovery that the lines corresponded to the spectral series of hydrogen but redshifted by a huge amount. In 3C48 the lines were redshifted by a speed corresponding to sixteen percent the speed of light, a hundred million miles per hour, and in 3C273 by twice that amount. This was an extraordinary mystery. What was the nature of strong radio emitting stars that were moving at speeds of hundreds of millions of miles per hour?