Certain Nebulae Adorn the Milky Way Like Jewels, and Scientists Aren't Sure Why

“Ghost stars,” or planetary nebulae, are some of the most beautiful objects in the cosmos. Formed when a red giant star burns through its nuclear fuel and sheds its outer layers, the nebulae (which have nothing to do with planets) expand outward in striking patterns. Some of these exhibit strange properties, according to a new paper, which studied 136 nebulae using the European Southern Observatory’s Very Large Telescope in Chile.