Gullies
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Vesta gullies look 'water cut'

7 December 2012 Last updated at 07:00 GMT

Scientists say they have seen features on Asteroid Vesta that look as though they could have been cut by some sort of fluid flow - possibly liquid water.

The gullies, seen running down the walls of some craters, were pictured by Nasa's Dawn probe.

Dawn's principal investigator Christopher Russell spoke to our correspondent Jonathan Amos.