Blazar 3C 279's historic gamma-ray flare can be seen in this image from the Large Area Telescope (LAT) on NASA's Fermi satellite. Gamma rays with energies from 100 million to 100 billion electron volts (eV) are shown; for comparison, visible light has energies between 2 and 3 eV. The image spans 150°, is shown in a stereographic projection, and represents an exposure from June 11 at 00:28 UT to June 17 at 08:17 UT. The scale bar at left shows an angular distance of 10°, which is about the width of a clenched fist at arm's length. During the flare, the blazar outshone the Vela pulsar, usually the brightest object in the gamma-ray sky.