How can Titan keep its atmosphere constant

Titan, orbiting Saturn, is the second largest moon in the Solar System. However, it has a diameter of only 40% of Earth’s size. So how does it manage to hold an atmosphere much denser than the one we are used to on our planet?

Titan’s internal structure. Source: Southwest Research Institute

Titan’s atmosphere

Planetary scientists at the Southwest Research Institute, in collaboration with the Carnegie Institution for Science, recently conducted an experimental study that sought to learn how a satellite, despite its small size, manages to retain an extremely dense atmosphere.

Titan is the second largest satellite in the Solar System after Ganymede. However, its diameter is only 40% of Earth’s, which means a mass that is hundreds of times smaller than our planet’s and a much weaker gravitational force. The latter usually means that molecules from the atmosphere of a space body need to transfer less energy to be lost in outer space.

The atmosphere on Titan should be much thinner than on Earth. But it is actually 1.5 times denser. The gas shell of the moon is 5% methane and 95% nitrogen and exists at very low temperatures.

Ever since the composition of Titan’s atmosphere was determined in 1944, scientists have wondered how the moon manages to maintain it. After all, by all calculations, it is kept stable by methane. And it would have to vaporize within 30 million years, after which the nitrogen would fall on the surface of the moon, like rain or snow, and freeze.

Inside source

The explanation for the existence of such an atmosphere was found many years ago. All it needs to exist is an influx of more and more gases from deep within the moon. But how exactly does that happen? New experiments were conducted for this purpose.

Their conditions were designed based on data from the Cassini-Huygens mission from 2004 through 2017. It suggested what the composition of Titan’s depths should be. Scientists created such materials and started heating them to temperatures between 250 and 500°C at a pressure of 10 bar.

These materials are complex mixtures of organic compounds, and when heated, they release carbon dioxide and methane. They were enough to keep Titan’s atmosphere stable. In the future, this data is planned to be used in the Dragonfly mission.

According to phys.org

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