As Cassini has been orbiting the planet Saturn, from time to time it’s had the opportunity to fly past Titan and take a peek. Over six years, this has added up to 78 flybys, each with different viewing geometry and illumination. But with some effort, it’s been enough for scientists to piece together a portrait of the icy world, as seen by Cassini’s VIMS (Visual and Infrared mapping Spectrometer) instrument in the infrared.
Here’s a quick bit of video showing the map Cassini’s human handlers have put together to date (direct link):
Here’s the accompanying text snippet:
An international team led by the University of Nantes has pieced together images gathered over six years by the Cassini mission to create a global mosaic of the surface of Titan. The global maps and animations of Saturn’s largest moon were presented by Stéphane Le Mouélic at the EPSC-DPS Joint Meeting 2011 in Nantes, France on Tuesday 4th October.
The team has compiled all the infrared images acquired by the Visual and Infrared Mapping Spectrometer (VIMS) during Cassini’s first seventy flybys of Titan. Fitting the pieces of the puzzle together is a painstaking task. The images must be corrected for differences in the illuminating conditions and each image is filtered on a pixel-by-pixel basis to screen out atmospheric distortions. Titan is veiled by a thick, opaque atmosphere composed mainly of nitrogen. It has clouds of methane and ethane and there is increasing evidence for methane rain. Only a few specific infrared wavelengths can penetrate the cloud and haze to provide a window down to Titan’s surface. An exotic frozen world with many Earth-like geological features has progressively emerged from darkness.
Or, you can read the whole press release (with links to yet more good imagery) here.