Description
This "planetary" nebula, so named because of its passing resemblance to a faint planet when seen through a telescope, is actually the remains of a star that has shed its outer layers in its death throes of existence. The end state of stars that are around the mass of our Sun, these nebula are quite numerous in the Universe. Their soft bluish glows are due to excited oxygen atoms formerly in the stars composition. The red glow is caused by excited hydrogen atoms. At the center, powering it all and responsible for the glow, is a stellar remnant called a White Dwarf. About the size of the Earth, these powerhouses give off copious ultraviolet light which is responsible for making the outer shells of gas glow.