October 1, 2013
NASA's Cassini spacecraft has detected propylene on Saturn's moon Titan. This is the first discovery of the material on any moon or planet, other than Earth, said the space agency.
Titan's atmosphere contains propylene, according to NASA.
"This chemical is all around us in everyday life, strung together in long chains to form a plastic called polypropylene," said Conor Nixon, a planetary scientist at NASA's Goddard Space Flight Center, in a news release.
The detection of the chemical fills in a mysterious gap in Titan observations that dates back to NASA's Voyager 1 spacecraft and its close flyby of this moon in 1980. The probe identified many of the gases in Titan's hazy brownish atmosphere as hydrocarbons, the chemicals that primarily make up petroleum and other fossil fuels on Earth.
On Titan, hydrocarbons form after sunlight breaks apart methane, the second-most plentiful gas in that atmosphere. The newly freed fragments can link up to form chains with two, three or more carbons.
Voyager detected all members of the one- and two-carbon families in Titan's atmosphere. From the three-carbon family, the spacecraft found propane, the heaviest member, and propyne, one of the lightest members. But the middle chemicals, one of which is propylene, were missing.
As researchers continued to discover more and more chemicals in Titan's atmosphere using ground- and space-based instruments, propylene was one that remained elusive. It was finally found as a result of more detailed analysis of the Cassini data.