Ring Nebula's True Form Revealed in Image from NASA's Hubble Telescope

The Ring Nebula is a distinctive landmark in the constellation Lyra, and it's often a popular target for amateur astronomers. Now, though, NASA's Hubble Space Telescope has revealed a new image of the nebula that shows the old, dying star's true shape.

Astronomers once thought that the nebula actually had a far less complex structure, which made it perfect for studies. Measuring about one light-year across, the nebula possesses gaseous material in its central region. Now, though, new images reveal the truly dynamic structure that the nebula possesses.

"The nebula is not like a bagel, but rather, it's like a jelly doughnut, because it's filled with material in the middle," said C. Robert O'Dell of Vanderbilt University in a news release. "With Hubble's detail, we see a completely different shape than what's been thought about historically for this classic nebula."

The new images seem to suggest that the nebula is composed of a ring wrapped around a blue, football-shaped structure. Each end of the structure protrudes out of the opposite sides of the ring. Since the nebula is tilted toward Earth, the astronomers can see the ring face-on. The blue structure within the nebula is actually the glow of helium--radiation from the white dwarf star at the very center of the complex is exciting the gas.

Yet what really surprised astronomers about the new image were the dark, irregular knots of dense gas embedded along the inner rim of the ring. Looking like spokes of a bicycle wheel, these gaseous tentacles formed when expanding hot gas pushed into cool gas ejected previously by the dying star. The knots are more resistant to erosion by the wave of ultraviolet light unleashed by the star. The new image may have allowed the researchers to match up these knots with the spikes of light around the bright, main ring, which are a shadow effect.

The findings have allowed researchers to learn a bit more about this expanding nebula. In addition, they reveal that even well-documented landmarks are surprising scientists with new features every day. Studying this nebula will also provide insight into our own sun's demise, which will occur in another six billion years.