Iron is a relatively abundant element in the universe and is one of the most common elements found in the rocky planets of our solar system—commonly referred to as terrestrial planets. These planets, which include Mercury, Venus, Earth, and Mars, formed from the protoplanetary disk, the cloud of gas and dust that surrounded the young Sun. This protoplanetary disk contained significant amounts of elements heavier than hydrogen and helium, including iron.
Mercury, for instance, is believed to have a core that is rich in iron, comprising the majority of its mass. Venus and Mars, like Earth, are also believed to possess substantial quantities of iron, mainly within their cores. The surfaces and crusts of these planets show evidence of iron oxides and other iron-bearing minerals. This suggests that, much like Earth, iron is a key component of these planets’ geology.
Iron’s prevalence on terrestrial planets is a consequence of the processes that characterize planet formation. During the formation phase, metals such as iron tend to sink towards the center of the planet, forming dense cores. This process explains the significant presence of iron in the interiors of these planets. Additionally, iron’s relatively high abundance in the solar nebula from which planets formed adds to its commonality on terrestrial planets.
In summary, iron is a widespread element across terrestrial planets, being a major component of their cores and present on their surfaces, much like on Earth.