It's hard to believe the above photo is even real. It looks like a soap bubble blown by some giant cosmic being, somehow floating through the vacuum of space. But it is real, and this colorful cosmic bubble is none other than the shell of a dying star.
Planetary nebulae -- so named for their round shape, and not for any relation to planets -- have a reputation for being kind of gorgeous. This one is called the Southern Owl Nebula, and it sits in the constellation Hydra. The nebula is at least four light years across. It was captured by the European Southern Observatory's Very Large Telescope in northern Chile, and released as part of their ESO Cosmic Gems initiative to use stunning space images to encourage public interest.
As beautiful as they are, these nebulae are but a blink of an eye in a star's life story. Nebulae form at the tail end of a star's life. After billions of years on the scene, their time as nebulae will only last a few tens of thousands of years.
Planetary nebulae grace the last years of red giant stars, when cast-off gas is ionized by the exposed core of the ravaged star -- now a white dwarf. Because our sun will one day (in a few billion years) swell into a red giant, we can expect our solar system to host a planetary nebula like this one in the distant future. Unfortunately all life on Earth will be long dead by that time, having been burned up by the sun's growing girth and heat.
Once the gasses fueling this brilliant color show have been fully expelled into interstellar space, the white dwarf inside will burn for another billion years or so, then cool off for another few billion once it has run out of fuel.
But although they're brief, nebulae have a huge role to play in the evolution of the universe. A nebula helps to send the materials formed by its star -- the heavy elements created by billions of years of fusion -- out into space, where they're recycled by newly formed stars. This helps seed the universe with the heavy, relatively new elements -- like hydrogen and carbon -- that helped form life as we know it.