Galaxy NGC 2842, Chandra X-ray image. This active spiral galaxy is in the constellation Ursa Major, and is about 150 million light years distant. Areas of the galaxy emitting X-rays are shown in blue, and include clouds of hot gas rising above and below the plane of the galactic spiral arms. The process is thought to be fuelled by young, hot stars and supernovae explosions in the galaxy. Called 'galactic chimneys', these plumes of hot gas spread heavy, metallic elements away from the galactic plane, into the surrounding halo. The grey/white structure of the galaxy was obtained by an optical telescope. X-ray data obtained on 18 December 2004 by the Chandra X-ray Observatory in Earth orbit.