A cloud half the size of the United States has been imaged on Saturn’s moon Titan by the Cassini spacecraft. The cloud may be responsible for the material that fills the lakes discovered last year by Cassini’s radar instrument. Cloaked by winter’s shadow, this cloud has now come into view as winter turns to spring. The cloud extends down to 60° north latitude, is roughly 2400 km in diameter, and engulfs almost the entire north pole of Titan.
The image was acquired on Dec. 29, 2006, by Cassini’s visual and infrared mapping spectrometer (VIMS). Scientific models predicted this cloud system but it had never been imaged in detail before. “We knew this cloud had to be there but were amazed at its size and structure,” said Christophe Sotin of the University of Nantes, France, a member of the VIMS team and distinguished visiting scientist at NASA’s Jet Propulsion Laboratory (Pasadena, CA). The same cloud system seen on Dec. 29 was still there two weeks later during the flyby, which took place on Jan. 13, even though observing conditions were less favorable than in December. Contact Christophe Sotin at [email protected]. (Photo courtesy of ESA)