The Galaxy Within Centaurus A . ... Credit Copyright: J. Keene ( SSC /Caltech) et al. JPL , Caltech , NASA Explanation: Peering deep inside Centaurus A, the closest active galaxy to Earth, the Spitzer Space Telescope's penetrating infrared cameras recorded this startling vista . About 1,000 light-years across, the twisted cosmic dust cloud apparently shaped like a parallelogram is likely the result of a smaller spiral galaxy falling into the giant Centaurus A . ... NASA Official: Jay Norris. ...