Supernova remnant SN 1006, composite image. This supernova remnant was discovered in AD 1006 by Chinese astronomers. The supernova was the brightest in recorded history. Today we see X-ray emissions from a ball of very hot gas (at a temperature of about 10 million degrees) expanding into the interstellar medium behind the shock wave produced by the explosion. This image combines optical (green), radio (red) and X-ray (blue) data from the Hubble Space Telescope (HST) and the Cerro Tololo Inter-American Observatory (CTIO), the Very Large Array (VLA) and Green Bank Telescope (GBT), and the Chandra X-ray Observatory (CXO). Supernova remnant SN 1006 is 7200 light years from Earth, in the constellation of Lupus.