The Veil Nebula, part of the Cygnus Loop supernova remnant
Supernova remnant in the constellation Cygnus, about 2000ly from Sol. The supernova exploded about 15,000 b.c.e. years ago and is still expanding forming a cloud of gas. The nebula is almost spherical with some bright filaments. The region has long been colonized by a number of exotic clades.
Supernova Remnant - Text by M. Alan Kazlev The expanding and cooling shell of gas and dust that is visible for thousands of years after a supernova. After a few tens of thousands of years supernova remnants mix with the interstellar medium and dissipate.