Dawn probe spies possible water-cut gullies on Vesta
By Jonathan Amos Science correspondent, BBC News, San Francisco
... "We're just putting it out there to the community; we're not suggesting anything hard and fast at this stage" ...
In the majority of cases (about 50 examples), the troughs trace simple descent lines and are presumably the consequence of loose rock or soil falling down the slope. But in a second, smaller group (11 examples), the pattern the gullies cut in the surface is quite different. They are complex; they are interlaced.
"The first group we call Type A. They're very typical of dry-mass wasting; the sort of thing you would get on Earth's Moon and on other, smaller asteroids. But the Type B gullies are the ones we think may have this liquid water origin; they have quite distinct morphologies. They are longer and narrower. They also interconnect, branching off one another" ...
"<It> would be cool enough just a few metres or even some centimetres beneath the surface that water could be preserved for a long time," said Prof Chris Russell, the principal investigator on the Dawn mission. "So we have some mechanisms like comets that might bring water to the surface - then it could be stored for some period of time" ...
http://www.bbc.co.uk/news/science-environment-20582704
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