NASA | Blazar Bonanza

A long time ago in a galaxy half the universe away, a flood of high-energy gamma rays began its journey to Earth. When they arrived in April, NASA’s Fermi Gamma-ray Space Telescope caught the outburst, which helped two ground-based gamma-ray observatories detect some of the highest-energy light ever seen from a galaxy so distant. Astronomers had assumed that light at different energies came from regions at different distances from the black hole. Gamma rays, the highest-energy form of light, were thought