Elongated dunes on Saturn's moon
Large areas of Saturn's moon Titan are believed to be covered by structures resembling terrestrial sand dunes. This is how scientists led by Ralph Lorenz from the University of Arizona interpret radar images taken by the Cassini spacecraft.
The images show alternating light and dark lines that span hundreds of kilometers and are mostly found near the lunar equator. They closely resemble satellite photos of desert regions of the world such as in Namibia or Rub al Khali in Arabia. From this optical analogy, the researchers conclude that Titan is also made up of deposited small granules that were piled up by the wind to form 150-meter-high dunes.
It is not known what material the Titan Dunes are made of. It could be organic matter or water ice. In any case, the existence of the deposits indicates an arid area with no vegetation-like structures or large areas of liquid - otherwise the granular material would have been caught by it.
The wind on Titan would only need to blow gently to transport the material due to the moon's low gravity. About ten centimeters per second would be sufficient. This wind strength fits well with the measurements made by the Huygens lander a few months ago and with the theoretical models of the lunar atmosphere.
