Titan 'half awake in chemical activity'
Washington: A lab experiment led by an Indian scientist at NASA's Jet Propulsion Laboratory (JPL), that simulates Saturn's moon Titan's atmosphere suggests that complex organic chemistry that could lead to the building blocks of life extends lower in the atmosphere.
The results have pointed out that another region on the moon could brew prebiotic materials.
"Scientists previously thought that as we got closer to the surface of Titan, the moon's atmospheric chemistry was basically inert and dull," Murthy Gudipati , the paper's lead author at JPL, said.
"Our experiment shows that's not true. The same kind of light that drives biological chemistry on Earth's surface could also drive chemistry on Titan, even though Titan receives far less light from the Sun and is much colder.
"Titan is not a sleeping giant in the lower atmosphere, but at least half awake in its chemical activity," he said.
Researchers have known that Titan has a thick, hazy atmosphere with hydrocarbons, including methane and ethane. The simple organic molecules can develop into smog-like, airborne molecules with carbon-nitrogen-hydrogen bonds, which astronomer Carl Sagan called "tholins."
"We've known that Titan's upper atmosphere is hospitable to the formation of complex organic molecules," co-author Mark Allen, principal investigator of the JPL Titan team, said.
"Now we know that sunlight in the Titan lower atmosphere can kick-start more complex organic chemistry in liquids and solids rather than just in gases," he added.
The team examined an ice form of dicyanoacetylene-a molecule detected on Titan related to a compound that turned brown after being exposed to ambient light in Allen's lab 40 years ago.
In this latest experiment, dicyanoacetylene was exposed to laser light at wavelengths as long as 355 nanometers.
The result was the formation of a brownish haze between the two panes of glass containing the experiment, confirming that organic-ice photochemistry at conditions like Titan's lower atmosphere could produce tholins.
The paper has been published in Nature Communications.