Black background. At image center is a colorful ring of gas and dust. The ring is a deep red along the outside. Moving inward toward the center of the ring, the colors change from red, to orange, to yellow, to pinkish-white, to a light blue sphere in the center.

Hubble Helix Nebula (NGC 7293)

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. In its center lies a white dwarf star.

Credits: NASA, NOAO, ESA, the Hubble Helix Nebula Team, M. Meixner (STScI), and T.A. Rector (NRAO)