Exploring Titan

Water and organic material – two main components of life – are suggested to exist on one of Saturn's moons, Titan, according to research of planetary scientist at John Hopkins University Applied Physics Laboratory Ralph Lorenz and his colleagues.

Although no direct evidence of life has been found on Titan, Lorenz said that the icy moon has similar fundamental processes as Earth, suggesting that Titan could serve as a laboratory to learn more about life's origins.

"Life as we know it requires liquid water, which is why this finding is interesting, but just having an ocean beneath the surface doesn't mean you're going to have advanced life," said Lorenz. "What Titan can tell us in all likelihood is a lot about the chemical processes that ultimately led towards life."

The Cassini-Huygens space orbiter-probe mission started in 2004 as a project to study Saturn's system as a whole, according to Lorenz. The mission is a cooperative effort of NASA, the European Space Agency and the Italian Space Agency.

As the Cassini orbiter rotated around Saturn, Lorenz said, its radar took pictures capturing one percent of Titan's surface every few months. Twenty percent of Titan's surface has been mapped since the mission began.

Christophe Sotin, a Jets Propulsion Laboratory research scientist at the California Institute of Technology, said that Titan's geographical features shifted by several tens of kilometers from a position that would be expected if Titan always faced the same side to Saturn. Lorenz attributed the shift to a disconnect between the moon's core and its surface – evidence of a liquid layer beneath a solid ice crust.

The existence of water is not atypical for icy moons, as others also have liquid interiors according to Lorenz. What sets Titan apart is the combination of water in addition to the previously discovered geological features and its atmosphere.

Lorenz said that Titan holds lakes of liquid ethane and methane around the poles and vast fields of "sand" dunes around the equator. He explained that sand referred to the size of the particles, which seemed to be organic simply in terms of bearing carbon.

Also, Titan's atmosphere makes the moon "exceptional," according to Sotin.

"There are hydrocarbons in the atmosphere and also the surface; therefore there is organic chemistry occurring in Titan," Sotin said.

Cassini is likely to continue for at least two more years, according to Lorenz, but approval from NASA is pending. A future mission to focus on Titan, he said, would take five to seven years to develop and possibly another seven years for an orbiter to just travel there.

Such a mission, Lorenz explained, would be pitched towards understanding Titan's chemistry with the current knowledge of Titan's diverse landscape and variable weather. Lorenz said the complexity of the reactions would be studied to make implications about other planetary environments and how life originates.

Research on Titan could be applicable to Earth studies, according to Lorenz, because of the similar fundamental processes. Both have lakes, clouds and rain, yet on Earth these are composed of water whereas on Titan, they are composed of methane.

"Methane is a condensed greenhouse gas just like water vapor, so you get similar kinds of climate feedbacks," said Lorenz.

"It is an environment that yearns to be explored in more detail," he said.

Cassini's last Titan flyby was on March 23. The future of the Cassini mission relies on the condition of the spacecraft and available funding.

Written by Kate Liebers

Reviewed by Jeffrey Kost

Published by Pooja Ghatalia.

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