The constellation Lyra is
also home to one of the most famous objects on the sky. M57, the
Ring Nebula, is probably the finest example of a planetary
nebula anywhere in the sky. It was formed when a star about the
size of the Sun neared the end of its life cycle and shed its
outer shell of hydrogen gas. This shell of material is
illuminated by the remains of the star, known as a white dwarf,
in the center. The nebula is well known for its beautiful
colors, ranging from red to yellow, green, and blue. Its age is
estimated at about 5,500 years. Its distance from Earth is not
very well known. M57 can easily be seen in a small telescope,
but a large instrument is needed to see the 13th magnitude star
at its center.
