Mercury's mysterious makeup may be the result of a grazing "hit and run" collision between two similar-sized protoplanets in the early solar system, a new study suggests.
Mercury, the smallest and innermost planet in our solar system, has a number of unusual characteristics that have long puzzled scientists. Despite being only slightly larger than Earth's moon, Mercury is extraordinarily dense. It boasts a disproportionately large, iron-rich core that makes up about 60% of its mass — twice that of other rocky planets such as Earth, Venus or Mars — challenging commonly accepted theories of planetary formation.
