which was created in a supernova that was first observed in A.D. 1054.
Most glowing gaseous nebulae emit light because one or more bright stars heat them. The Veil Nebula appears to be an exception to this rule. It is heated instead through collision with surrounding interstellar gases. The material in the Veil Nebula is moving so rapidly that the interstellar medium, although nearly a complete vacuum, provides enough friction to heat it and cause it to shine. Although there are many stars in this image, most are far from the nebula and just happen to lie along the same line of sight.
The unusual structure of the Veil Nebula has long interested astronomers, who believe the thin
