'Smog' forming on Saturn moon studied

PASADENA, Calif., Feb. 5 (UPI) -- NASA says its Cassini mission has seen in more detail than ever before how aerosols create "smog" in the highest part of the atmosphere of Saturn's moon Titan.

Understanding aerosol formation at Titan could help predict the behavior of similar smoggy aerosol layers on Earth, NASA's Jet Propulsion Laboratory in Pasadena, Calif., reported Monday.

A study published in the Proceedings of the National Academy of Sciences said Titan's trademark reddish-brown smog appears to begin with solar radiation affecting molecules of nitrogen and methane in the ionosphere, creating a soup of negative and positive ions.

Collisions among the organic molecules and the ions create bigger and more complex aerosols, researchers said, eventually creating hydrocarbons that rain down on Titan's surface and form lakes, channels and dunes.

The scientists studied Titan's "smog" with three Cassini instruments: the plasma spectrometer, the ion and neutral mass spectrometer, and the radio and plasma wave science experiment, JPL said.

The Cassini mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency, and is managed for them by JPL.