A titanic effort identifies moon's smog

UK scientists have identified the molecules in the atmosphere of Saturn's largest moon, Titan, that give rise to its hazy smog-like atmosphere. Data collected using the Cassini plasma spectrometer and a UK-run onboard electron spectrometer have picked out a surprising cloud of very heavy organic ions 1000 km above Titan's surface, some of which have masses of up to 8000 Daltons. Ions of 80-350 Daltons are thought to form from photochemically from atmospheric methane and nitrogen and include polycyclic aromatic hydrocarbons (PAHs) and related compounds containing nitrogen. The much larger 8000 Dalton compounds have been identified as heteropolymers called tholins.