Water Ice on Vesta Too?

What Caused This?
Credit NASA / JPL

NASA / JPL announced on December 6th the discovery of “long , narrow, sinuous” gullies on the asteroid Vesta.  Although no one is claiming at this point that the gullies are clear evidence of water ice,  the features bear a remarkable resemblance to similar water carved chasms on Earth and on Mars.  The features in question differ markedly from other, short and wide gullies which are believed to be caused by landslides.    Following the confirmation of water ice in permanently  shadowed craters on Mercury last month, it does not seem too much of a stretch to believe similar deposits could be common throughout the inner solar system.

The ion powered Dawn spacecraft departed Vesta in route to mega asteroid / dwarf planet  Ceres, also in the main asteroid belt, on September 5th. Using the ion propulsion system, Dawn has achieved a change in speed of more than 7.1 kilometers since launch, becoming in the process the highest performing spacecraft of all time, using that measure.  It is due to arrive in orbit around Ceres in 2015, where it is expected to confirm the presence of an enormous quantity of water ice, potentially exceeding the cumulative volume of fresh water on Earth.