Active galaxies flare and fade in Fermi telescope all-sky movie

		VIDEO: This all-sky movie shows Fermi LAT counts of gamma rays with energies greater than 300 million electron volts from August 4 to October 30, 2008. Brighter colors indicate brighter gamma-ray... Click here for more information.

The gamma-ray sky comes alive in a movie made from data acquired by NASA's Fermi Gamma-ray Space Telescope during its first three months of operations. Gamma rays from sources near and far turn the sky into a hypnotic froth. The sun arcs serenely across the northern sky as active galaxies called blazars flare up and fade out.