Fizzy lakes on Titan?
Simulations by NASA scientists show that the lakes on Saturn's moon Titan could be bubbly.
Images by the Cassini spacecraft show features in Titan’s sea Ligeia Mare that change over time. Are these ‘magic islands’ caused by fizzy bubbles?
Image credit: NASA/JPL-Caltech/ASI/Cornell
Saturn’s moon Titan may have fizzy lakes and seas that erupt like a can of fizzy pop being opened, according to NASA.
Titan is the second largest moon in our Solar System, after Jupiter’s Ganymede. The Cassini spacecraft has revealed its surface to support rivers and lakes of liquid ethane and methane, which can also fall as rain from the moon’s sky.
Researchers at NASA’s Jet Propulsion Laboratory simulated the conditions on Titan and found that nitrogen could be dissolved in the liquid methane, and changes in temperature, air pressure or composition could cause the nitrogen to separate from the solution and form bubbles. This is the same process that occurs when opening a can or bottle of fizzy juice.
Read more about Cassini's observations of Titan from BBC Sky at Night Magazine
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"Our experiments showed that when methane-rich liquids mix with ethane-rich ones, for example from a heavy rain, or when runoff from a methane river mixes into an ethane-rich lake, the nitrogen is less able to stay in solution," says Michael Malaska of JPL, who led the study.
While this is interesting from a chemistry point of view, the bubbles could potentially cause problems for any future probes sent to explore Titan’s seas.
But the simulations may also have solved a mystery of disappearing islands on Titan. Cassini has made several flybys of the moon, and spotted small patches of land disappearing and then reappearing. At the time, scientists had proposed this could be the result of bubbles in the seas, and these new results support that theory.
"In effect, it's as though the lakes of Titan breathe nitrogen," Malaska says. "As they cool, they can absorb more of the gas, 'inhaling’. And as they warm, the liquid's capacity is reduced, so they 'exhale.'"