There are areas on Callisto (one of Jupiter's moons) covered with spire-shaped mountains (up to 100 metres tall). These icy mountains are believed to be slowly eroding over aeons, the ice subliming away, leaving behind dust that was bound in the ice. This accumulating dark material may then absorb enough heat from the sun to continue the melting of the ice. Io, Europa and Ganymede can be seen near Jupiter. This painting is owned by a company called Callisto and they are a leading supplier for Deep Space communications. see http://www.callisto-space.com