No one is saying that, exactly. Even if there were a liquid, it wouldn’t be water, as the asteroid is far to distant from the sun and much too cold for liquid water.
But scientists are puzzling over the observations of Jennifer Scully, a University of California scientist who is working on the Vesta project. She has seen gullies and what seem to be flows down craters on the surface of the asteroid that so far have defied explanation.
On Earth, the answer would be simple: the gullies are created by liquid water flows eroding the surrounding landscape. On Mars, similar featured have been observed and attributed to liquid water in the Red Planet’s distant past.
But similar shapes on Vesta can have no such explanations, which means that if other erosive forces are at play, then even agreed-upon answers for Mars may be in question:
Indeed, scientists have suggested various explanations for gullies on Mars since fresh-looking gullies were discovered in images from NASA’s Mars Global Surveyor in 2000. Some of the proposed Martian mechanisms involve water, some carbon dioxide, and some neither. One study in 2010 suggested that carbon-dioxide frost was causing fresh flows of sand on the Red Planet.
This is one more reason that scientific data is always important and often surprising: study of two completely different systems may reveal new facts that change our understanding of both systems. It isn’t rare, in fact, it is what science is all about.