In the late 18th century, Charles Messier (MESS-ee-ay) catalogued all the cloudy patches he could find in the sky so that he would not mistake them for comets. A cloudy patch in Lyra was the 57th nebula listed in his catalog. M57, now known as the Ring Nebula, appears like a little smoke ring peacefully wafting through the starry night. However, this doughnut of glowing hydrogen gas, speaks of the violent explosion of the outer layers of a once massive star. Near the center of the ring, only its hot bluish core remains intact.