By Ron Cowen
Saturn’s moon Titan has an environment that resembles Earth’s at the time that life first got a foothold, new findings from the Cassini spacecraft suggest.
Two close flybys have gathered fresh evidence that ammonia, most likely mixed with water ice, has recently erupted onto the surface of the moon. The likely presence of ammonia on Titan’s icy surface, combined with the abundance of methane and nitrogen in the moon’s thick atmosphere, together suggest that Titan may host a prebiotic brew, says Cassini scientist Robert Nelson of NASA’s Jet Propulsion Laboratory in Pasadena, Calif.
The findings, reported by Nelson August 5 in Rio de Janeiro at a meeting of the International Astronomical Union, are based on data gathered by Cassini’s Visual and Infrared Mapping Spectrometer during November and December 2008. The spectrometer records emissions from seven different infrared “windows” — wavelength bands at which radiation from material on Titan’s surface can penetrate the moon’s methane-rich shroud and reach the spacecraft.