Fermi Catalogs the Gamma ray Sky . ... Credit Copyright: NASA , DOE , International Fermi LAT Collaboration Explanation: What shines in the gamma-ray sky? ... Fermi's sources of cosmic gamma-rays feature nature's most energetic particle accelerators , ultimately producing 100 MeV to 100 GeV photons, photons with more than 50 million to 50 billion times the energy of visible light . ... To locate the cataloged gamma-ray sources, just slide your cursor over the map. ... NASA Official: Jay Norris. ...