dipper@utastro.UUCP (Debbie Byrd) (10/23/85)
Today's the birthday of the first radio astronomer. More on Karl Jansky -- when we come back. October 23 The Birth of Radio Astronomy Today's the birthday of Karl Jansky -- the first person to discover radio waves from outer space. Both radio waves and light waves are forms of electromagnetic energy -- both are emitted by a variety of objects in outer space. We can easily see light coming from the sun and stars. But no one knew about cosmic radio waves until 1932 -- and the discovery of Karl Jansky. Jansky worked for Bell Telephone at the time. He was trying to understand static in radio telephone reception. Local thunderstorms turned out to be one source. Distant thunderstorms were another. But in addition there was a third source of radio static -- a steady hiss that reached a peak in intensity a little earlier each day. In fact, the peak of the static came about four minutes earlier each day. A normal day is 24 hours, from one noon -- when the sun is highest in the sky -- to the next. But stars reach their highest point in the sky at a slightly different interval -- because of Earth's motion around the sun. Stars reach their highest points at intervals of about 23 hours 56 minutes -- about four minutes earlier each day. Because the unknown static in Jansky's receiver peaked at this same interval -- he realized it was coming from outer space. He soon identified the source as the center of our own Milky Way galaxy. Today we know many other sources of cosmic radio waves -- from some ordinary objects like our sun -- to exotic ones like quasars and pulsars. Script by Deborah Byrd. (c) Copyright 1984, 1985 McDonald Observatory, University of Texas at Austin