The ever-present fog of energetic gamma rays permeating the universe isn't created by what astronomers expected, new observations from NASA's Fermi Gamma-ray Space Telescope reveal, leaving scientists with a new cosmic mystery to solve.
The sky glows in gamma rays even far away from well-known bright sources, such as pulsars and gas clouds within our own Milky Way galaxy or the most luminous active galaxies. Conventionally, astronomers thought that the accumulated glow of active galactic nuclei -- black hole-powered jets emanating from active galaxies -- accounted for most of this gamma-ray background.
"Thanks to Fermi, we now know for certain that this is not the case,
This is comforting news. I always suspected it was weird out there. Now I know.
I believe you mean "Mysterious gamma ray source is mysterious" ^.^