Plastic Compound Found in Saturn’s Moon Atmosphere

Scientists at NASA have found propylene — a basic element of plastic food packaging and storage containers — on Saturn’s moon, Titan.

Wow, you think, humans can be trashy with plastic containers and scatter them around to far-reaching places. But all the way to Saturn?


It’s not what you think. NASA spacecraft began detecting hydrocarbons, the chemicals that comprise a large part of petroleum and other fossil fuels on Earth, when Voyager 1 flew by Titan in 1980, reports Science Codex. But it wasn’t until the Cassini spacecraft, currently orbiting Saturn and making occasional fly-bys of Titan, continued the investigation and found the propylene.

It’s the first time the plastic ingredient, propylene, has been detected anywhere else except Earth. Science Codex explains further how the spacecraft made the discovery:

A small amount of propylene was identified in Titan’s lower atmosphere by Cassini’s Composite Infrared Spectrometer (CIRS). This instrument measures the infrared light, or heat radiation, emitted from Saturn and its moons in much the same way our hands feel the warmth of a fire. Propylene is the first molecule to be discovered on Titan using CIRS. By isolating the same signal at various altitudes within the lower atmosphere, researchers identified the chemical with a high degree of confidence.

“This chemical is all around us in everyday life, strung together in long chains to form a plastic called polypropylene,” says Conor Nixon, a planetary scientist at NASA’s Goddard Space Flight Center in Greenbelt, MD, and lead author of the paper that was published in September in Astrophysical Journal Letters. “That plastic container at the grocery store with the recycling code 5 on the bottom — that’s polypropylene.”

Hydrocarbons formed in Titan’s atmosphere when sunlight broke down methane, a plentiful gas there. The fragments link to form chains with two, three or more carbons. Cassini and other NASA instruments back here on Earth had found many chemicals in the moon’s atmosphere, but propylene remained elusive until further analysis of CIRS data.

“This measurement was very difficult to make because propylene’s weak signature is crowded by related chemicals with much stronger signals,” says Michael Flasar, Goddard scientist and principal investigator for CIRS. “This success boosts our confidence that we will find still more chemicals long hidden in Titan’s atmosphere.”

Much like Cassini’s spectrometer can measure chemicals’ signatures in gases, Polymer Solutions’ spectrometer can measure chemicals’ signatures from solids. The analysis of a sample can reveal the cause of a failure in various products, such as medical implants, children’s toys, paints, and woven materials.

Source: “NASA’s Cassini spacecraft finds ingredient of household plastic in space,” Science Codex, 9/30/13
Source: “Propylene on Titan,” YouTube
Image by public domain.