Earth and sky, gamma ray image. Composite image from the Large Area Telescope of the Fermi Gamma-ray Space Telescope (FGST). Observations made when the Milky Way's galactic centre was near the zenith, directly overhead, are mapped to the centre of the image, forming a faint diagonal line. Gamma ray emissions from cosmic ray impacts with Earth's atmosphere form a ring. Combining the two observations forms an all-sky projection from Fermi's orbital perspective. The gamma ray intensity is colour-coded from low (blue) to high (yellow) on a logarithmic scale. The FGST was launched in June 2008. Image published in December 2013.