Giant solar gaseous discs put on spectacular show in Sun`s sky

Last Updated: Sunday, July 7, 2013 - 11:32

Washington: Scientists studying the solar atmosphere are building their own collection of fascinating moving features that they`ve spotted in the Sun`s sky.

The unusual solar prominences include a giant disc that rotates for several hours, feathery streamers as long as fifty Earths, a super-heated jet striking the top of a prominence and twisted ribbons flowing in opposite directions at a million kilometers per hour.

The features were discovered by Dr. Xing Li and PhD student Jeff Smith of Aberystwyth University using the Atmospheric Imaging Assembly (AIA) telescope on board the Solar Dynamics Observatory (SDO) satellite.

Prominences are-relatively-cold gaseous features, with temperatures around 5,000 degrees Celsius compared to the surrounding the hot solar atmosphere of about 1-2 million degrees.

They can be seen as towering features extending outwards from the Sun`s surface, often in the shape of a loop.

They are called filaments when viewed against the solar disc, appearing as dark stripes because the cold gases they contain absorb the light emitted from below.

Solar prominences and filaments supply most of the material released in coronal mass ejections, vast eruptions from the Sun`s atmosphere that can cause space weather and create geomagnetic storms on Earth.

Rotating discs in solar prominences were first observed decades ago, using ground-based telescopes, and have puzzled solar physicists since.

The new SDO observations of a rotating disc reveal that the feature covers a temperature range from a few thousand to one million degrees Celsius.

Li and Smith believe that the rotation is caused by turbulence produced at the interface of two gases of enormously different temperatures.

"We think the rotation is produced when hot gases enter a cold medium in an organized fashion. The magnetic field serves as a thermal barrier between the two media. The resulting rotation can last hours," Li said.

ANI



First Published: Sunday, July 7, 2013 - 11:32

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