Photograph
The Western Veil Nebula (NGC 6960)
Part of the Veil Nebula complex in the constellation Cygnus, located about 2,400 light-years from Earth. It is the remnant of a supernova—the explosion of a massive star that occurred roughly 10,000 years ago.
Beyond the frame
The delicate filaments are not the entire supernova remnant. They trace the locations where the expanding shock wave plows through interstellar gas, heating it until it begins to glow. Behind these glowing strands, the interior has already been largely swept clear by the explosion. In effect, we are seeing only the edge of an enormous expanding bubble more than 100 light-years across—a snapshot of a shock wave that is still racing through our galaxy today.