An upcoming NASA space mission to the asteroid 16 Psyche will allow us to examine rare metallic asteroids in the solar system. Unlike most asteroids, Psyche appears to be composed largely of iron and nickel instead of rocky rubble. Such metal-rich asteroids are rare and are thought to have formed when large scale impacts stripped away much of the outer material, leaving behind the inner metallic cores that cooled and solidified from the outside in. During this cooling process, an alloy of residual melted pockets of iron, nickel, and lighter elements like sulfur might have flowed to the surface through fluid-filled cracks called dikes, coating a topmost, rocky layer in a process known as ferrovolcanism. READ MORE