New radar images of Saturn's moon Titan reveal dunes, hills, valleys and rivers that scientist say look a lot like home.
But on Titan, which is frigid and shrouded in smog, the features are likely carved in ice rather than solid ground.
The detailed view is of a bright area on Titan called Xanadu. It's about the size of Australia and has been studied from afar for years. Now scientists are getting a better look with NASA's Cassini spacecraft. Radar is bounced off the surface to generate an image that cannot be made using visible-light observations because the orbiting spacecraft can't see through the moon's thick atmosphere.
The observations reveal mountains about as high as the Appalachians.
"Surprisingly, this cold, faraway region has geological features remarkably like Earth," said Jonathan Lunine, a Cassini researcher at the University of Arizona.
The river channels are likely carved by liquid methane or ethane, as the moon is too cold for water to be liquid.
"Although Titan gets far less sunlight and is much smaller and colder than Earth, Xanadu is no longer just a mere bright spot, but a land where rivers flow down to a sunless sea," Lunine said.
Liquid methane might fall as rain or trickle from springs to create the rivers, Lunine and his colleagues figure. Perhaps the rivers carry grains of material that accumulate as dunes elsewhere.
"This land is heavily tortured, convoluted and filled with hills and mountains," said Steve Wall, the Cassini radar team's deputy leader at NASA's Jet Propulsion Laboratory. "Xanadu has been washed clean. What is left underneath looks like very porous water ice, maybe filled with caverns."
Image Gallery: Imagining Saturn and Titan
Image Gallery: Cassini's Latest Discoveries
Cassini Sees Xanadu on Saturn's Moon Titan