Cosmic rays and Titan's organic molecules (earthsky.org)

Posted by Paul Scott Anderson in Space | February 25, 2020

Saturn’s largest moon, Titan, is rich in organic compounds, the chemical compounds upon which all known life is based. Both Titan’s surface and its atmosphere contain these compounds. Since Titan is thought to be similar to an early Earth, scientists are interested in how these molecules are formed.

Now, researchers say they’ve found a major clue about this prebiotic process, called abiogenesis, the process by which life arises from non-living matter. Using the Atacama Large Millimeter/submillimeter Array (ALMA), they have discovered a chemical footprint in Titan’s atmosphere, the result of cosmic rays – high-energy particles from deep space – hitting the atmosphere and affecting the formation of nitrogen-bearing organic molecules.

The new peer-reviewed results were announced by ALMA on February 14, 2020, and were published in The Astrophysical Journal on February 17, 2020.

This is the first time that such processes have been observed directly on Titan. The research team found faint, but firm signals of acetonitrile (CH3CN) and its rare isotopomer CH3C15N in the ALMA data. Takahiro Iino, of the University of Tokyo, is the study lead author. He said in a statement: