Titan, captured during a flyby on April 16, 2005 by the Cassini spacecraft (NASA/JPL/Space Science Institute)
Saturn’s largest moon, Titan, is an extraordinary world. Among the solar system’s more than 150 known moons, Titan is the only one with a substantial atmosphere. That atmosphere is made mostly of nitrogen, like Earth’s, but with a surface pressure 50 percent higher. And Titan is the only place in the solar system besides Earth known to definitely have liquids in the form of rivers, lakes, and seas on its surface, although the liquids are methane and ethane. The largest seas are hundreds of feet deep and hundreds of miles wide.
Beneath Titan’s thick crust of water ice is more liquid—an ocean primarily of water rather than methane. With a thick atmosphere and liquid water, Titan could conceivably harbor life that uses different chemistry than on Earth. Sarah Horst, a planetary scientist and associate professor in the earth and planetary sciences department at Johns Hopkins University, delves into the complex chemistry of Titan’s atmosphere and what it means for the potential habitability of the moon.
The Grand Tour of the Solar System series treks to the Sun and the four inner terrestrial planets before traveling outward to the asteroid belt, four Jovian planets, and beyond. At each session, a professional astronomer explores a solar system body, presenting the latest research.
Following the talk and a question-and-answer period, Peter Plavchan, a professor of physics and astronomy at George Mason University, brings that night’s sky right into participants’ living rooms via remote control of the university observatory, weather permitting.
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