The “Cygnus Bubble” nebula may actually be a cylinder that is being seen from one of its ends. This image was taken with the Kitt Peak Mayall 4-metre telescope in Arizona (Image: Travis A. Rector/U of Alaska Anchorage/Heidi Schweiker/NOAO)

IT LOOKS like a soap bubble or perhaps even a camera fault, but the image at right is a newly discovered planetary nebula.

Planetary nebulae, which got their name after being misidentified by early astronomers, are formed when an ageing star weighing up to eight times the mass of the sun ejects its outer layers as clouds of luminous gas (see …