Venus at 2.3 micron
This picture of the Venusian atmosphere is the negative of a night-side infrared image acquired by the VIRTIS instrument on board Venus Express on 29 July 2006, at a distance of about 65 000 kilometres from the surface.
The image shows the observed radiation at 2.3 μm, but in negative: bright regions correspond to regions with less infrared radiation coming from the surface due to intervening cloud cover which absorbs it. Therefore the bright regions in this image follow the cloud structure.
At the centre of the image is 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 the planet's high-speed winds.
The cloudy (bright) region visible at the top-right of the image is situated below 60° south latitude, and represents the transition to the region where the atmosphere is dominated by the effects of the powerful double-eyed south polar vortex.