sentences:  Assuming that the "Giant impact hypothesis" is correct, there were never real seas or oceans on the Moon, only perhaps a little moisture (liquid or ice) in some places, when the Moon had a thin atmosphere created by degassing of volcanoes or impacts of icy bodies.The "Dawn" space probe found possible evidence of past water flow on the asteroid Vesta, leading to speculation of underground reservoirs of water-ice.Astronomers speculate that Venus had liquid water and perhaps oceans in its very early history.