The Ring Nebula (M57)

The Ring Nebula in the constellation Lyra is a planetary nebula, formed when a star expels a shell of hot ionized gas. This is part of the life cycle of many stars, as they exhaust their primary hydrogen fuel begin forming oxygen and carbon in their cores. It a relatively short-lived phase lasting a few thousand years. The originating star is visible in the middle of the ring. The ring has been expanding for about 1600 years. We are viewing the structure from a vantage point near the central axis. The view from the side would look something like the Dumbbell Nebula. The Ring Nebula is about 2,300 light years from earth and about 1 light year across.