NASA's Hubble images Little Gem Nebula in space

WASHINGTON: NASA's Hubble telescope has captured a stunning image of a planetary nebula, which shows a bright and colourful cloud of dust and gas, located roughly 6,000 light-years away from Earth.

The planetary nebula called NGC 6818, also known as the Little Gem Nebula, was spotted by Hubble as a colourful bubble located in the constellation of Sagittarius, roughly 6,000 light-years away from our planet.

The Hubble image of the Little Gem Nebula shows two layers of gas (with dust): a spherical outer region and a brighter, vase-shaped interior bubble.

The rich glow of the cloud is just over half a light-year across -- humongous compared to its tiny central star -- but still a little gem on a cosmic scale.

When stars like the Sun enter retirement, they shed their outer layers into space to create glowing clouds of gas called planetary nebulae.

This ejection of mass is uneven, and planetary nebulae can have very complex shapes.

NGC 6818 shows knotty filament-like structures and distinct layers of material, with a bright and enclosed central bubble surrounded by a larger, more diffuse cloud.

Scientists believe that the stellar wind from the central star propels the outflowing material, sculpting the elongated shape of NGC 6818.

"As this fast wind smashes through the slower-moving cloud it creates particularly bright blowouts at the bubble's outer layers," scientists said.

Hubble had previously imaged this nebula back in 1997 with its Wide Field Planetary Camera 2, using a mix of filters that highlighted emission from ionised oxygen and hydrogen.

This image, while from the same camera, uses different filters to show a different view of the nebula.