July 21, 2012
Lack Of Erosion On Titan Puzzles Scientists
redOrbit Staff & Wire Reports - Your Universe Online
By studying photographs of Saturn's moon Titan, researchers from a pair of US universities have discovered that the satellite's river networks caused little erosion in some areas, leading them to believe that either erosion there is exceptionally slow or that some other phenomenon wiped out older riverbeds and landforms.
The research, which was conducted by experts from the Massachusetts Institute of Technology and the University of Tennessee at Knoxville and was the subject of a July 20 report by Jennifer Chu of the MIT News Office, analyzed images obtained from the Cassini-Huygens spacecraft in 2004.
That probe, which flew by Titan while it was orbiting Saturn, penetrated the thick atmosphere of the satellite, which has long hampered astronomer's study of the moon. Beyond the methane and the nitrogen, Cassini-Huygens found "an icy terrain carved out over millions of years by rivers of liquid methane, similar to how rivers of water have etched into Earth´s rocky continents," according to Chu.
Their findings, which will be published in the Journal of Geophysical Research-Planets, suggests that Titan may have recently undergone a major transformation, as the surface of the four-billion-year-old moon appears to be far younger, perhaps even less and a quarter of the age of the rest of the satellite.
“It´s a surface that should have eroded much more than what we´re seeing, if the river networks have been active for a long time,” Taylor Perron, an assistant professor of geology at MIT, told Chu. “It raises some very interesting questions about what has been happening on Titan in the last billion years.”
He added that the process could be similar to what occurs on our own planet, telling the MIT News Service, “We don´t have many impact craters on Earth“¦ People flock to them because they´re so few, and one explanation is that Earth´s continents are always eroding or being covered with sediment. That may be the case on Titan, too.”
However, while on Earth, scientists have been able to identify a variety of factors -- including shifting tectonic plates, volcanic eruptions, and glaciers -- which have reshaped the planet's surface, it will be difficult for experts to identify what geological phenomena could be responsible for the changes on Titan. Part of that is because the Cassini photographs are poor resolution and share little information about the land's depth or elevation.
“It´s an interesting challenge,” Perron says. “It´s almost like we were thrown back a few centuries, before there were many topographic maps, and we only had maps showing where the rivers are.”
“It´s a weirdly Earth-like place, even with this exotic combination of materials and temperatures,” he added. “And so you can still say something definitive about the erosion. It´s the same physics.”