What's the Latest Development?
NASA's Cassini spacecraft, which has been orbiting Saturn since 2004, recently sent back a high-resolution radar image of a 250-mile-long river flowing across Titan, Saturn's largest moon. This first-ever high-resolution shot shows the river emptying into the southern end of Kraken Mare, a sea estimated to be five times bigger than the US' Lake Superior. With its direction, size, and other features, scientists are comparing it to Earth's Nile River.
What's the Big Idea?
Yes, the observation team knows it's a river of liquid because its entire length appears dark in the image. And no, the liquid is not water: Titan has a hydrocarbon-based weather system, so it's most likely ethane and methane. According to Cassini radar team associate Jani Radebaugh, "[T]he relative straightness of the river valley suggests it follows the trace of at least one fault...[which] may not imply plate tectonics, like on Earth, but still lead to the opening of basins and perhaps to the formation of the giant seas themselves." Such features were first hinted at through images sent by the Huygens probe in 2005, but it no longer sends data home, unlike Cassini, whose mission has been extended to 2017.
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