Saturn's moon Titan seen in infrared
NASA / JPL-Caltech / University of Nantes / University of Arizona
A circular molecule on Saturn's moon Titan can help form precursors for life. This connection has never been seen in the atmosphere of a planet or moon.
The molecule is called cyclopropenylidene and consists of three carbon atoms in a ring with two bonded hydrogen atoms. Conor Nixon of NASA's Goddard Space Flight Center in Maryland and his colleagues discovered it with the Atacama Large Millimeter / Submillimeter Array in Chile in the thick atmosphere of Titan.
It was a surprise to find this molecule on titanium. It's extremely reactive – when it hits other particles it usually reacts quickly with them chemically to form new compounds. For this reason, it was previously only seen in weak gas and dust clouds in interstellar space. It kind of lasts in the upper layers of Titan's sky.
Such circular molecules tend to act as building blocks for essential molecules like DNA and RNA. "This is a really small building block, but you can always use it to build bigger things," says Nixon. "I don't think anyone would necessarily believe that there are microbes on Titan, but the fact that we can form complex molecules like these on Titan could help us tell things like the beginning of life on Earth."
Conditions on Titan could now be similar to those on Earth at the beginning of planetary history, when the air was dominated by methane instead of oxygen. Studying its life potential could help us learn about the beginnings of life here too.
Titan has the greatest variety of molecules on any moon or planet we've studied, says Nixon. "It's kind of a happy hunting ground for new things," he says. "Molecules like this are almost an early warning sign that chemistry is more exciting."
At the moment we can only search for it from Earth, but the Dragonfly spacecraft, slated to launch in 2027, will be examining the surface of Titan at close range.
Journal reference: The Astronomical Journal, DOI: 10.3847 / 1538-3881 / abb679
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