HCN is important also because it is widespread in astrochemical environments, having been identified in the interstellar medium (10), and on various bodies such as comets , planets , moons , and dwarf planets (15). The small nitrile is the second-most abundant product expected from the atmospheric chemistry of Saturn's moon Titan . An estimated two meters of HCN, or its equivalent in reaction products, has been deposited on Titan's over the last 1 Gyr . This atmospheric chemistry is driven by radiation from the sun and Saturn's magnetosphere , and also 50 produces our second protagonist ethane, the most abundant photochemically-produced material on Titan (5.5 m Gyr -1 ), which along with methane are major contributors to the evolution of Titan's yellow haze .