The Rosette Nebula is a large, circular emission nebula located in the constellation Monoceros (the Unicorn), about 5,000 light-years from Earth. It spans over 100 light-years across and gets its name from its rose-like appearance. The nebula glows due to ionized hydrogen gas illuminated by young, hot stars at its center.

NGC 2244 is the open star cluster at the heart of the Rosette Nebula. The stars in this cluster are very young—only a few million years old—and extremely massive and bright. Their intense ultraviolet radiation sculpts and lights up the surrounding nebula, creating that dramatic glowing effect.