科学美国人60秒:Titan Sports Hydrocarbon Nile

You’ve heard the old saying: "Da Nile ain’t just a river in Egypt." And it’s true. The Nile, as it turns out, is also a river on Titan—provided you squint and take a little creative license with your nomenclature.

NASA’s Cassini orbiter recently took some radar readings of the Saturnian moon Titan. And what Cassini spotted there was a river system that NASA likens to a miniature version of the Nile River on Earth. It’s long and relatively straight, just like the real Nile. But unlike the famed Egyptian river, Titan’s river flows not with water but with liquid hydrocarbons such as ethane and methane.

Titan, the largest moon of Saturn, is the only place in the solar system other than Earth where large bodies of liquid coat the surface. In Titan’s north polar region, the river flows some 400 kilometers into Ligeia Mare, a giant sea of hydrocarbons.

Recently planetary scientists proposed that NASA launch a floating spacecraft to explore the seas of Titan. But when NASA opted for a Mars lander instead, the plans for a space boat were scuttled.

—John Matson