Apr 8, 2011 07:37 GMT  ·  By

According to the conclusions of a new astronomical study, it would appear that the atmospheric vortex that forms above the South Pole of Venus changes its shape daily, and sometimes even more often.

At times, the vortex looks like an 8, or like an S, but it can also take on a range of other shapes as well. A counterpart for this atmospheric feature exists at the planet's north pole.

Both formations are caused by the fact that the Venusian atmosphere is traveling extremely fast, much more so than those of Earth or Mars. The disturbances in air flow that appear as a result create these hot and huge vortices.

Clouds whirl at tremendous speeds above the planet's pole, a lot faster than they do at the Equator for example. Scientists measured the speed of clouds above Venus, and determined that they were about 60 times faster than the surface of our neighboring planet.

One interesting thing about these atmospheric structures is that they are not really storms, such as visible on Earth or Saturn's moon Titan. They do not produce any kind of rain or lightning, that may be indicative of other processes going on above Venus as well.

“Filaments swirl around one or two bright – that is, warmer – centers. Sometimes the shape looks like an S or an 8, sometimes it shows three bright centers, but mostly it's irregular,” explains David Luz.

The expert is a researcher and planetary scientist at the University of Lisbon in Spain, Space reports.

Past investigations of the Venusian poles revealed that the south vortex had a diameter of roughly 2,000 kilometers (1,200 miles), and also that it took on an oval shape as it was spinning.

But recent data sent back by the Venus Express orbiter, which belongs to the European Space Agency (ESA), showed that large-scale, inner structure of the South Pole vortex was changing constantly. The overall shape of the atmospheric whirl changed in tune with this, at least once every 24 hours.

In addition to rotating around its center, the vortex itself also spins around the South Pole, on a path that constantly keeps it about 3 degrees of latitude away from the actual geographic pole. It takes between 5-10 days for one such rotation to be completed.

The new study indicates that the interactions developing between Venus and its atmosphere are significantly more complex than anyone thought. “This is a change in our understanding that general circulation models of Venus will need to take into account,” Luz explains.

Experts are now trying to figure out what goes on with the North Pole vortex, and of it behaves in the same way as its southern counterpart.

“For the moment we don't know, because Venus Express' highly elliptical orbit brings it too close to the north pole, making it impossible to do similar imaging studies. We can see only a very small region,” the expert explains.

Details of the new work appear in the April 7 online issue of the top journal Science. ESA has been operating the Venus Express orbiter since 2006, and the spacecraft's operations helped experts boost their understanding of our neighboring planet considerably.