Monday, October 1, 2012

Energetic Space Tornadoes hold the key to Solar Mystery

A team of European scientists has discovered super-hot and super-fast tornados on the Sun, which may help answer a number of outstanding questions in the realm of physics.

Writing in the journal Nature, they report that these `magnetic tornadoes reach speeds of up to 10,000 kilometres per hour, completely dwarfing anything found on Earth.

For images and videos visit www.solartornado.info 

In fact the fastest recorded tornado on Earth only reached speeds of approximately 486 km per hour, and was by no means an example of a common occurrence.

These magnetic tornadoes on the Sun, created by rotating magnetic field structures which force plasma to move in spirals, are not only common but may hold the answer to a long-standing physics conundrum: why the surface of the Sun is cooler than its outermost atmospheric layer.

Think of any fire and it is common knowledge (and sense) that the closer one gets to the fire, the hotter it gets.

The Sun however doesn't quite follow this logic. Its central core is an amazing 15,000,000 degrees Celsius and its surface cools to 5,500 degrees Celsius - following the logic that the further away, the cooler it gets.

The Sun cools to a mere 4,300 degrees Celsius to where a layer of the Sun's atmosphere, the photosphere, meets the chromosphere. In the chromosphere, however, things become topsy-turvy.

When the chromosphere begins to merge with the Sun's outermost atmospheric layer, the corona, the temperature rises to 100,000 degrees Celsius and continues to increase to a scorching 2,000,000 degrees Celsius in the part of the corona that is farthest from the Sun.

This, almost accordion-like sequence of heat, has puzzled many scientists. A puzzle which this recent discovery of magnetic tornadoes may have solved.

Professor Robertus Erdélyi, head of the Solar Physics and Space Plasma Research Centre (SP2RC) of the University of Sheffield's School of Mathematics and Statistics explains: 'One of the major problems in modern astrophysics is why the atmosphere of a star, like our own Sun, is considerably hotter than its surface?

Imagine, that you climb a mountain, e.g. a munro in the Scottish highlands, and it becomes hotter as you go higher and higher.

'It is understood that the energy originates from below the Sun's surface, but how this massive amount of energy travels up to the solar atmosphere surrounding it is a mystery.'

'We believe we have found evidence in the form of rotating magnetic structures - solar tornadoes - that channel the necessary energy in the form of magnetic waves to heat the magnetised solar plasma.'

'We report here the discovery of ubiquitous magnetic solar tornadoes and their signature in the hottest areas of the Sun's atmosphere where the temperature is a few millions of degree kelvin, about thousands of kilometres from the Sun's surface. This is a major step in the field.'

It is estimated that there are as many as 11,000 of these magnetic tornadoes above the Sun's surface at any time, and each one more than 1,600 km wide. Despite their number and size, they have never been seen until now.

Read the full article at EU CORDIS

Read more info on Space Tornadoes here at Institute of Theoretical Physics, University Oslo

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