Astronomers believe they've worked out the source of a mysterious burst of gamma rays that irradiated the Earth in the 8th century.
Physicists say they've found more evidence for the existence of dark matter, in the form of gamma rays emanating from the center of the galaxy.
Scientists say the Crab Pulsar is blasting out gamma rays at a higher rate than can be explained by current scientific models.
A mysterious gamma ray flash observed by the Swift satellite in late March was probably caused by a star being swallowed by a massive black hole, astronomers have concluded.
Astronomers are poring over data from what they say is one of the most puzzling cosmic blasts ever observed.
Scientists have for the first time discovered that antimatter is regularly being produced on Earth - by thunderstorms.
NASA's Fermi Gamma-ray Space Telescope has discovered a massive structure spreading halfway across the Milky Way.