Astronomy Picture of the Day . ... 19.11.2015 . ... Image Data: Hubble Space Telescope , European Southern Observatory Explanation: What's the closest active galaxy to planet Earth? ... Near the galaxy's center , left over cosmic debris is steadily being consumed by a central black hole with a billion times the mass of the Sun. As in other active galaxies , that process generates the radio, X-ray, and gamma-ray energy radiated by Centaurus A. January . ... Publications with keywords: Centaurus A . ...