Spying Titan's weather
Evidence of changing weather patterns in the skies over Titan's southern region are revealed in these false-colour images from the NASA/ESA/ASI Cassini-Huygens spacecraft.
The spacecraft's Visual Infrared Mapping Spectrometer captured these images during recent fly-bys of largest Saturn's satellite.
The image on the left was obtained during the 26 October Titan fly-by, from a distance of some 200 000 kilometres. Titan's skies are cloud-free, except for a patch of clouds observed over the south pole near the bottom of the image.
In contrast, the image on the right shows a recent view of this same area of Titan obtained seven weeks later during the second close fly-by on 13 December, from a distance of 225 000 kilometres. This image clearly shows that several extensive patches of clouds have formed over temperate latitudes.
The appearance of these clouds reveals the existence of weather. Tracking of these features is currently under way by scientists, who hope to gain a better understanding of global circulation, regional weather patterns and localised meteorology in Titan's skies.
The colours red, green, and blue represent near-infrared images obtained at 2.01 micron, 2.83 micron and 2.13 micron respectively. These colours explore the surface and atmosphere of Titan with varying effectiveness.
The bright clouds at a relatively high altitude (here, about 30 kilometres above the ground) residing above most of the atmospheric absorption appear whitish in these representations, as they reflect sunlight effectively in all three near-infrared colours.
The Cassini-Huygens mission is a co-operative project of NASA, ESA and ASI, the Italian space agency.
Credits: NASA/JPL/University of Arizona