An H II Region

 An H II Region
This emission nebula, M16, called the Eagle Nebula because of its shape, surrounds a star cluster. It is so named because it was the sixteenth
object in the Messier Catalogue of astronomical objects. Star formation is presently occurring in M16, which is located 7000 ly from
Earth in the constellation of Serpens Cauda (the Serpent’s Tail). Several bright, hot O and B stars are responsible for the ionizing radiation that
causes the gases to glow. Inset: Star formation is occurring inside these dark pillars of gas and dust. Intense ultraviolet radiation from
existing massive stars off to the right of this image is evaporating the dense cores in the pillars, thereby prematurely terminating star
formation there. Newly revealed stars are visible at the tips of the columns