The Helix Nebula is an example of a planetary nebula. Though it looks like a bubble or eye from Earth's point of view, the Helix is actually a trillion-mile-long tunnel of glowing gases. This Hubble ...
NASA Missions Study the Crab Nebula|A new composite image of the Crab Nebula features X-rays from Chandra (blue and white), optical data from Hubble (purple), and infrared data from Spitzer (pink).