Chuck Bednar for redOrbit.com – @BednarChuck
Already known to be similar to Earth, researchers from University College London reported Thursday in the journal Geophysical Research Letters that Titan, the largest of Saturn’s moons, is even more like our home planet than previously believed.
According to Space.com, previous research has shown that Earth and Titan are the only objects in the solar system that have rainfall, rivers, and oceans. Furthermore, both objects possess rocky ground, plate tectonics, and a thick atmosphere. These new studies show that the two celestial bodies also both have polar winds.
As the authors explained in their study, Titan’s polar winds are pulling gas from the atmosphere, and seven years worth of data collected by the Cassini probe found interactions between the moon’s atmosphere, the solar magnetic field, and solar radiation. These interactions create a wind of hydrocarbons and nitriles that is blown away from the polar regions into space.
Polar wind and atmospheric loss
Evidence of these winds were captured by Cassini’s Plasma Spectrometer (CAPS) as the probe made a series of nearly two-dozen flybys around Titan, the researchers explained in a statement. The new observations help explain data collected by the probe several years ago which revealed the moon was losing approximately seven metric tons of particulate matter each day.
Hydrocarbons are a type of molecules that includes methane, and nitriles are molecules with nitrogen and carbon bound tightly together, the study authors said. In the new study, the team found that the atmospheric loss of these particles is driven by polar winds powered by sunlight, the solar magnetic field, and particles in the moon’s upper atmosphere.
Lead investigator Andrew Coates from the UCL Mullard Space Science Laboratory and his co-authors explained that Titan’s atmosphere is comprised primarily of nitrogen and methane, with 50 percent higher pressure at its surface than on Earth.
“Although Titan is ten times further from the Sun than Earth is, its upper atmosphere is still bathed in light,” Coates said. “When the light hits molecules in Titan’s ionosphere, it ejects negatively charged electrons out of the hydrocarbon and nitrile molecules, leaving a positively charged particle behind. These electrons can be traced by the CAPS instrument, and easily distinguished from other electrons, as they propagate through the surrounding magnetic field.”
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