Nearly 650 light-years from Earth, the Helix Nebula—pictured in a new composite image from NASA's Spitzer Space Telescope and the orbiting Galaxy Evolution Explorer (GALEX)—offers a glimpse of what our sun might one day look like.

Many scientists expect the sun to die in about five billion years and become, like the Helix, a planetary nebula. Bounded by expanding bubbles of glowing gas, planetary nebulae were misnamed because, when seen through early telescopes, the gas clouds resembled gas-giant planets such as Jupiter or Neptune.