This picture shows the South Pole of Venus. It was taken in infrared light. The yellow area at the bottom is the daytime side of the planet which is lit by the Sun. The two "eyes" of the polar vortex are the red blobs near the pole (at the center of the picture). Click on image for full size (65 Kb) Image courtesy ESA/VIRTIS/INAF-IASF/Obs. de Paris-LESIA.

A vortex is a swirling, circular movement of air and clouds... like in a tornado or hurricane. The plural form of vortex is "vortices". The planet Venus has vortices in its atmosphere above each of its poles. A NASA spacecraft spotted vortices above the North Pole in 1978. A spacecraft from the European Space Agency (ESA) found vortices at the South Pole in 2006.

Some other planets have polar vortices. A polar vortex forms in the winter at each pole on Earth. Saturn also has polar vortices. The polar vortices on Venus are unusual. Each polar vortex has two "eyes" that the winds and clouds swirl around. The vortices on Venus are double vortices. Scientists aren't quite sure why Venus has these odd double vortices.

Sometimes large, bright clouds form over the poles of Venus. They often form and go away pretty quickly. These clouds reflect a lot of sunlight back into space. They make Venus look much brighter. Scientists think the vortices "stir up" the atmosphere, causing the clouds to form.

Venus has a very dense, very hot atmosphere. The thick atmosphere spreads the heat around evenly. It is just as hot on the nighttime side of Venus as it is on the daytime side. On Earth, the poles are much colder than the equator. On Venus, it is just as hot at the poles as it is near the equator. The spin axis of Venus is not tilted very much, so Venus doesn't really have seasons. It is always hot on Venus... in both the summer and the winter.