Image of the Cygnus Loop Supernova Remnant (also known as the Veil Nebula) taken during the EUVE all-sky survey in 1992. A white circle with the size of the full Moon is shown for scale. The Cygnus Loop is the remnant of a supernova which exploded 20,000 years ago, at a distance of about 2500 light years from the Earth. The image shows 100 Angstrom extreme ultraviolet radiation from the remnant caused by glowing gas at 1 - 3 million degrees Kelvin.