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Vortexes at the South Pole of Venus (infrared) - frame 1
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High velocity winds are known to spin westwards around the planet, and to take only four days to complete a rotation. This 'super-rotation', combined with the natural recycling of hot air in the atmosphere, would induce the formation of a vortex structure over each pole. But why two vortexes?
"We still know very little about the mechanisms by which the super-rotation and the polar vortexes are linked," said Håkan Svedhem, ESA’s Venus Express Project Scientist. "Also, we are still not able to explain why the global atmospheric circulation of the planet results in a double and not single vortex formation at the poles. However the mission is just at the beginning and it's doing fine; we expect this and many other long-standing mysteries to be addressed and possibly solved by Venus Express" he added. Atmospheric vortexes are very complex structures that are very difficult to model, even on Earth.
Thanks to these first pictures, it has also been possible to observe the presence of a collar of cold air around the vortex structure, possibly due to the recycling of cold air downwards.
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(Dettagli)
