A planetary nebula (PN, plural PNe), is a type of emission nebula consisting of an expanding, glowing shell of ionized gas ejected from red giant stars late in their lives. The term "planetary nebula" ...

Using more than 100 spectacular images from the Hubble Space Telescope, Cosmic Butterflies explores the beauty of the most mysterious celestial objects in space, planetary nebulae. The mystery begins ...

"We can use the Ring Nebula as our laboratory to study how planetary nebulae form and evolve." The so-called "planetary nebulae" is a misnomer that dates back to the 18th century, when the ...