Ngc7293

The Helix Nebula is a stunning example of a planetary nebula -— a glowing shell of ionized gas expelled by a dying star. The star expels its outer layers of gas, leaving only its small, hot core. Radiation from the core energizes that gas, causing it to glow in a rainbow of colors. About 650 light-years away, the Helix is one of the closest and brightest such nebulae.

Here are two of the prettiest nebulae in the sky: the Helix Nebula (NGC7293) and the Ring Nebula (M57).