The Ring Nebula is the expanding outer atmosphere of a star that has reached the end of its red-giant phase. The exposed hot core in the center floods the surrounding gas with ultraviolet light, causing different elements to glow at characteristic wavelengths.

Although it looks like a simple ring from Earth, M57 is a three-dimensional shell with a more complex barrel-like structure. We happen to view it close to its axis, producing the bright oval rim and darker central opening that make it one of the sky’s most recognizable planetary nebulae.

The Ring’s familiar oval is only the bright inner portion of a much larger three-dimensional structure. Spectroscopy and deep imaging show expanding shells and faint outer material surrounding the hot central remnant, a white dwarf that now floods the ejected gas with ultraviolet radiation and causes oxygen, hydrogen, and nitrogen to glow at different wavelengths.

M57 lies in Lyra, the Lyre. In Greek mythology the instrument belonged to Orpheus, whose music was said to charm animals, trees, stones, and even the rulers of the underworld.

After Orpheus died, his lyre was placed among the stars. The Ring Nebula itself is far too faint to have entered ancient stories, but it sits inside one of the sky’s most musical mythic constellations, anchored by the brilliant star Vega.

Orpheus’s lyre was said to produce music so powerful that it could move animals, trees, and even stones. In the story of his descent into the underworld, that music persuades Hades to release Eurydice on the condition that Orpheus not look back before reaching the upper world—a condition he breaks at the final moment. The lyre’s place in the sky preserves the instrument as much as the musician.