Centaurus A is one of the most powerful sources of radio waves in the sky. Only the Sun and two other radio galaxies, Cassiopeia A  and Cygnus A, are stronger sources of these waves. In this false color image, red represents the hottest, most energetic areas, and blue the coolest. 
    This radio image shows the typical radio structure of a galaxy: two huge lobes emerge from the galaxy’s hot nucleus. About 7 arc minutes, or 36,000 light years, separate the two lobes. The image shows only the galaxy’s inner lobes. The outer ones are about 21/2 million light years long and stretch a full 10 degrees across the sky—20 times the apparent size of a full Moon. That is even greater than the distance between the Milky