Mittwoch, 4. November 2015 - 08:31 Uhr
Saturn's largest moon Titan is a hazy, cold and complicated world complete with lakes of liquid methane and ethane, a nitrogen-rich atmosphere and even hydrocarbon dunes.
Titan's fields of dunes cover an area about the size of the United States, according to NASA. An image taken in July 2015 by the Cassini spacecraft reveals two of the dune regions, called Fensal in the north and Aztlan in the south, the space agency said.
Cassini captured this image of the large moon from a distance of 450,000 miles away.
"Cassini's cameras have frequently monitored the surface of Titan (3,200 miles or 5,150 kilometers across) to look for changes in its features over the course of the mission," NASA said in a statement.
"Any changes would help scientists better understand different phenomena like winds and dune formation on this strangely earth-like moon."
Titan is like a world ripped from the pages of an old-school science fiction novel.
According to NASA, it's possible that Titan actually has tectonic activity occurring beneath its surface — like the continental plates on Earth.
Titan also has clouds in its atmosphere that rain methane onto the surface of the moon, NASA has found. (On Earth, methane is usually a gas or in frozen form underneath the surface of the sea, but Titan is so cold that the chemical compound can actually exist as a liquid.)
The Huygens spacecraft landed on Titan in 2005 after being carried to Saturn by Cassini, and once it touched down on the moon, it found "an area that appeared to be a floodplain, complete with rounded cobblestones of rock-hard water ice," NASA said in a statement.
"The ground around the landing site was soaked in liquid methane. Scientists think Huygens might have come to rest in an area where rains wash nearby hills clean of dark hydrocarbon particles that drift down from the skies," NASA added.
The moon is actually the only world in the solar system, aside from Earth, known to have lakes and seas on its surface.
Cassini is going to get a relatively close-up view of Titan on November 13 when it flies by the moon at only 7,406 miles from its surface.