The Eagle Has Risen: Stellar Spire in the Eagle Nebula. A billowing tower of gas and dust rises from the stellar nursery known as the Eagle Nebula. This small piece of the Eagle Nebula is 57 trillion miles long trillion km).
In NASA's recent Hubble Space Telescope picture of the Crab Nebula, a dead star's ghoulish green glow can be seen—some light-years from Earth. Despite the neutron star being dead, astronomers say the color is due to "the star's tell-tale heart.
When nuclear fusion in a star, much like our Sun ceases, the star dies. It expels it's outer gaseous layers and leaves behind a tiny, hot, dense core called a white dwarf. The cosmic result - a planetary nebula.