The Ring Nebula is a planetary nebula, which is an emission nebula of ionized gas. This gas is a "shell" puffed off from the surface of an old, red giant star as it reaches the end of its life. The shell is a cylinder we are seeing from "end on," and it is expanding at around 30 km per second. The center of the nebula is expanding faster than the ring. The central star is a white dwarf about the size of earth and it glows at around Magnitude 14.7.