Clouds of charged particles form a halo around the Perseus galaxy cluster in this combined radio and optical view. The radio view, in red, is produced by particles that are accelerated by collisions between galaxies or by powerful jets from supermassive black holes. The halo spans about 1.3 million light-years. [Gendron-Marsolais et al.; NRAO/AUI/NSF; NASA; SDSS]