[guardian.co.uk] Observatory snaps cosmic soap bubble

Observatory snaps cosmic soap bubble

The rare, spherical planetary nebula was first spotted by an amateur astronomer last year but has been photographed in all its perfection for the first time.

Astronomical objects generally don't live up to their names, with constellations like Taurus or Aries bearing little resemblance to a bull or ram. Blame ancient stargazers with overactive imaginations.

The same cannot be said for the recently discovered Soap Bubble Nebula, however. A transparent, near-perfect sphere, it hangs in the night sky like a bubble floating on the wind.

It was first spotted by amateur astronomer Dave Jurasevich in California on 6 July 2008, but it wasn't until last month that the Kitt Peak National Observatory in Arizona was able to capture the clear image above.

Officially known as PN G75.5+1.7, the Soap Bubble is an example of a planetary nebula. These are formed when the nuclear fusion reactions at the centre of a star can no longer support its structure. External layers of the star are forced outwards, drifting through space for thousands of years.

These gases are ionised by ultraviolet light from the remaining core and glow, resulting in nebulae that take on a variety of shapes and sizes. Most are elliptical or cigar-shaped, but the Soap Bubble Nebula is a rare sphere.

The label "planetary nebula" is another astronomical misnomer, as the objects are completely unrelated to planets. The name originates from the 18th century, when telescopes weren't powerful enough to distinguish nebulae from gas giant planets.

Most famous of the gas giants is Jupiter, which also benefited from the vigilant observation of an amateur astronomer this week. Australian Anthony Wesley discovered that a comet or asteroid had crashed into Jupiter, and emailed Nasa to let them know.



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