The Cat's Eye nebula is one of the most well known objects in the night sky. Also known as NGC 6543, the nebula gives us a glimpse into the future of our own Sun. Eventually, the sun-like stars expand and shed their outer layers near the end of their 10-billion year life span. This shedding will throw material out into the universe creating this awesome halo.
The halo is about 6 light-years across and is the outermost layer of the planetary nebula. This layer of ionized gas was the first to be shed by the central star. Some of these gasses have been traveling through space for nearly 100,000 years. The nebula is comprised mostly of ionized oxygen (blue-green), hydrogen, and nitrogen (both in red).