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Complex meteorology at Venus   The false-colour view is the composite of three infrared images acquired by the Ultraviolet, Visible and Near-Infrared Mapping Spectrometer (VIRTIS) on board ESA's Venus Express on 22 July 2006, at a time interval of about 30 minutes from each other and from a distance of about 65 000 kilometres over the planet's surface. Venus was in the night side.
The image, taken at a wavelength of 1.7-micrometre, shows the thermal radiation emitted from about 15-20 kilometres altitude. The brighter the colour (towards white), the more radiation comes from the surface, so the less cloudy the region in the line of sight between the view and the spacecraft is.  This picture of the Venusian atmosphere is the 'negative' of a night-side infrared image acquired by the VIRTIS instrument on board ESA's Venus Express on 29 July 2006, from a distance of about 65 000 kilometres from the surface. At the centre of the image, taken at 2.3-micrometre wavelength, it is possible to see a large cloud extending toward the bottom-right part of the view. The cloud is about 2000 kilometres long and 500 kilometres wide. It presents the peculiar elongated shape of clouds at Venus, which is due to high-speed winds.
The very cloudy region visible at the top-right of the image is situated beyond 60º South latitude, and represents the transition to the region where the atmosphere is dominated by the effects of the powerful South double polar vortex. Release date: 13 October 2006 |