Astrophysicists at the University of Oslo have observed a series of magnetic supertornadoes, swirling around the Sun's atmosphere. The plasma tornadoes — which number in the thousands and extend for thousands of miles across — may explain why the Sun's atmosphere is way hotter than its surface.
By using both space-based and ground telescopes, a research team led by Sven Wedemeyer-Böhm discovered 14 of these tornadoes which are made of swirling, searing-hot plasma. Each of them are roughly 1,800 miles high and and spin at a rate of 9,000 miles per hour. The University of Oslo researchers have been hot on the trail of these tornadoes since 2008, but couldn't confirm their existence until now.
Based on their observations, the researchers believe that there are about 11,000 of these twisters swirling around the Sun at any given time. And by using computer simulations, they feel that they can provide an explanation as to why the Sun's upper atmosphere is 300 times hotter than its surface.
Common sense would suggest that the Sun's temperature decreases outwards, but earlier measurements don't support that assumption. This has led researchers like Wedemeyer-Böhm to suspect that something must be pulling the heat to the atmosphere from the surface.
Solar tornadoes may provide a solution to the problem. By using computer models, Wedemeyer-Böhm's team was able to replicate the results of actual observations of the Sun made by the Swedish 1-m Solar Telescope and NASA's space-based Solar Dynamics Observatory. According to their models, solar tornadoes appear to form when hot surface particles surge up into the atmosphere and then sink back down. The downward motion of the particles rotates the Sun's magnetic field lines, causing the formation of vortices.
Speaking through a release, Wedemeyer-Böhm noted, "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 magnetized solar plasma."
These tornadoes, each of which lasts for about a dozen minutes at a time, can extend thousands of kilometers into the star's corona, transporting the hot surface plasma up into the atmosphere.
The researchers are now working on gathering more observations of the Sun's tornadoes.
Via National Geographic. Images via Wedemeyer-Böhm and VAPOR.