Plastic Ingredient Detected on Saturn’s Moon Titan

WIRED

By peering into the hydrocarbon haze of Saturn’s moon Titan, NASA’s Cassini spacecraft has made the first off-world detection of a molecule called propylene, one of the most important starting products of the modern plastic industry.

Propylene, also known as propene, is one of the simplest organic compounds, made from a chain of three carbons. On Earth, it is a byproduct of oil refining and other fossil fuel extraction processes. Humans use it as a raw material in creating many of the products in our world, including films, storage containers, and car bumpers. The molecule is also created naturally by some tree species and given off as a combustion product in forest fires.

Cassini detected propylene using its infrared spectrometer. Finding the molecule wasn’t too surprising — Titan is full of many different hydrocarbons including methane and propane — but spotting propylene has thus far eluded scientists. Previous missions had found other organic molecules with a three-carbon backbone, yet propylene was missing. Since it’s the lightest and simplest of this chemical family, its non-existence on Titan was perplexing. Researchers used Cassini’s data to sift through the hydrocarbon noise and finally extract propylene’s relatively weak signal. Their results appear today in the Astrophysical Journal Letters.