An Energetic Radio Galaxy . ... Credit Copyright: NASA , NRAO , VLA , HST , WFPC 2, M. Longair ( U. Cambridge ) Explanation: The radio and optical emission seen in the above superposed images of the radio galaxy 3C368 indicate that energetic processes are at work. A radio galaxy is a galaxy that is visible to radio telescopes. ... The optical light is shown above in red and the radio emission in blue contours. Currently, one can only guess what causes the unusual radio and optical features. ...