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Hubble Telescope Captures
Saturn's Eerie Twin Aurorae
jimbon | Sabtu, 13 Februari 2010 | 09:47 WIB

Astronomers had a rare chance to view Saturn with its rings edge on. It meant they could study the planets Northern and Southern lights

KOMPAS.com - A spectacular light show on Saturn has been captured in unique new photos of the ringed planet. The aurora images captured by the Hubble Space Telescope (HST) were made possible by a rare chance to see the planet with its rings edge-on and both poles in view.

It takes Saturn almost 30 years to orbit the Sun, and during that time such a picture opportunity occurs only twice. The images show glowing aurorae flickering at each pole - Saturn's equivalent of the Northern and Southern Lights on Earth.

The phenomena are caused by the "Solar Wind" - streams of electrically charged sub-atomic particles emitted by the Sun - interacting with molecules in the atmosphere. As on Earth, the particles are channelled to the poles by the planet's magnetic field.

Astronomers studying the images found subtle differences between Saturn's northern and southern aurorae. The bright oval-shaped area containing the northern aurora was slightly smaller and more intense than its opposite number at the south pole.

This implies that Saturn's magnetic field is not equally distributed across the planet. Because it is stronger in the north, the solar particles are accelerated to higher energies as they fly through the northern atmosphere.

Dr Jonathan Nichols, a member of the Hubble team from the University of Leicester, said: 'Hubble has proved to be one of mankind's most important scientific tools, and this is the first time that a group in the UK has led an HST programme to observe the aurorae on another world.'

Hubble will never capture such images again because the telescope is due to be decommissioned before the same view of Saturn is repeated.

'It is particularly exciting to know that these images are unique to science,' said Dr Nichols.

'They have not, and will never again, be obtained using Hubble. This is because HST pictured Saturn at a very special vantage point, near its equatorial plane.

'Due to Saturn's long orbit, HST will not see this view again in its lifetime. This sustained series of images of simultaneous north-south aurora are important scientifically, since they cannot be obtained at any other planet, including Earth.

'They tell us a great deal about the nature of the planet's magnetic field and the processes which generate aurorae in a way not possible at Earth.'




Sumber :
The Daily Mail