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.
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.