Everything in this universe ends including stars. As stars burn through their stash of nuclear fuel, their cores begin to shrink. Like anything else that has been created, they cling onto life for as long as they can.
Before entering oblivion, they enter one final stage of life. An intergalactic cloud of ionized particles is formed as gases are cast off from the dying star. A planetary nebulae is born.
Planetary nebulae exist briefly and are spectacular.
You can’t see them with your naked eyes so a telescope is needed. The Dumbbell Nebulae in the constellation Vulpecula was the first planetary nebulae to be observed by comet hunter Charles Messier in 1764. He listed it in his famous Messier catalogue as M27.
Everyday, NASA apod web site features a different astronomical picture of the day with a brief explanation. On February 18, 2011 it featured a spectacular mosaic of nine planetary nebulae including M27. You can see it at http://apod.nasa.gov/apod/ap110218.html
- Milky Way Gems Now Visible in Telescopes (space.com)
- Picture of the Day – A Dazzling Planetary Nebula (spacefellowship.com)
- M57, the Ring Nebula (computerphysicslab.wordpress.com)
- Picture of the Day – Glowing Waves (spacefellowship.com)
- The Stingray Nebula and XKCD (scienceblogs.com)
- Picture of the Day – Hubble Peers Deeply into the Eagle Nebula (spacefellowship.com)