When a star explodes the debris cloud expands extremely quickly. In this process, the gas becomes increasingly thin until, at some stage, it mixes with the ubiquitous interstellar gas and is no longer recognisable. The Veil Nebula is more than 15 000 years old and covers an area in the sky that is equal to six full moons. The section shown here is called Witch's Broom Nebula.
The picture superimposes three photos taken using a special filter. Various elements are detectable: hydrogen appears red, oxygen blue and sulphur green. The bright star is in the foreground and has nothing to do with the nebula.
Credits: Wisconsin Indiana Yale & NOAO Observatory, T. A. Rector (U. Alaska), AURA, NSF.