The first map showing the global geology of Saturn's largest moon, Titan, is complete and completely reveals a dynamic world of dunes, lakes, plains, craters and other terrains.
Planetary geologist David Williams of Arizona State University's School of Earth and Space Exploration works with a team of researchers led by planetary geologist Rosalie Lopez at NASA's Jet Propulsion Laboratory in Pasadena, CA to map this map of Titan. The map and their findings, which include the relative age of Titan's geological terrains, were recently published in the journal Nature Astronomy .
Titanium is the only planetary body in our solar system other than Earth that is known to have a stable fluid on its surface. But instead of pouring water from clouds and filling the lakes and seas, like on Earth, on Titan what is raining down is methane and ethane – hydrocarbons that we think are gases but which act as liquids in a frigid climate of Titan.
"Titanium has an active methane-based hydrological cycle that has formed a complex geological landscape, making its surface one of the most diverse geologically diverse solar systems," says lead author Lopez.
"Despite the different materials, temperatures and gravitational fields between Earth and Titan, many surface characteristics are similar between the two worlds and can be interpreted as products of the same geological processes. The map shows that different geological terrains have a clear distribution with latitude worldwide and that some terrains cover much more area than others, "says Lopez.
The Lopes team uses data from NASA's Cassini mission, which operated between 2004 and 2017 and performed more than 120 mercury-sized moon flywheels in Titan. In particular, they used data from Cassini's radar to infiltrate the opaque atmosphere of Titan's nitrogen and methane. In addition, the team uses data from Cassini's visible and infrared instruments, which were able to capture some of Titan's larger geological features through matte methane.
"This study is an example of using combined datasets and tools," said Lopez. "Although we did not have global synthetic aperture radar (SAR) coverage, we used data from other instruments and other radar modes to benchmark different terrain units, so we can infer terrain even in areas where we do not have it "No SAR coverage."
Williams' role in Titan mapping was to work with the JPL team to identify what geological units could be determined using radar images first and then extrapolate these one qi in non-radar-covered regions, Williams builds on his experience in radar imaging in NASA's Magellan Venus orbit and from a previous Titan regional geological map he developed.
"Cassini's mission revealed that Titan is a geologically active world where hydrocarbons methane and ethane play the role that water plays on Earth," Williams said. "These hydrocarbons flow on the surface, flow into streams and rivers, accumulate in lakes and seas and evaporate into the atmosphere. It's a pretty amazing world!"
Williams, who is also director of the Ronald Greeley Center for Planetary Studies at AIS, has considerable experience in geologic maps of small and unusual planetary objects, including the Jupiter Io volcanic moon, the asteroid Vesta, the planet Dwarf Ceres and now Titan .
"We had meetings at ACS earlier this decade to figure out how to map Titanium with higher resolution radar and lower resolution visible images," Williams explained. "The creators of Titan from NASA's Jet Propulsion Laboratory and Cornell University came to the ACS to understand how to map geologists of this strange new world."
The experience of mapping small and unusual planetary objects will help Williams fulfilled an important task that they will commit to in the next decade to make the first global geological map of the metal asteroid (16) Psyche, the purpose of the NASA Psyche-led ASU mission, scheduled to launch in 2022.
New models suggest Titan lakes are explosion craters
R. M. C. Lopes et al. Global geomorphological map of Saturn's lunar titanium, Natural astronomy (2019). DOI: 10.1038 / s41550-019-0917-6
Arizona State University
First global geological map of Saturn's largest moon, Titan, completed (2019, November 18)
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