The formation of Mercury remains an unsolved mystery. The planet closest to the sun has a disproportionately large metallic core—accounting for about 70% of its mass—and a relatively small rocky mantle. Until now, the most widely accepted explanation was that Mercury lost much of its crust and mantle after colliding catastrophically with a large celestial body. However, dynamic simulations show that this type of impact involving bodies of very different masses is extremely rare.
Collision between two bodies of similar mass may explain the formation of Mercury
