This radio image shows the eastern side of Sag A, which is believed to be a remnant of a supernova explosion. The shock wave from the blast excavated a bubble of material, leaving a “small” circular shell about 32 light years in radius. Also visible here are details of a large structure—8 arc minutes or 75 light years in diameter—that surrounds the eastern portion of Sag A. Two components can be seen: a large “halo” (in orange, yellow, green, and blue) and the network of protrusions popping up at right angles to the galactic plane.