Mercury’s Iron Heart: How Simulations Reveal the Origins of the Solar System’s Most Metal-Rich Planet

Haniyeh Tajer and colleagues used N-body simulations to explore why Mercury’s iron core is so large. They found that giant impacts alone cannot explain its composition. Instead, an iron-rich inner disk in the early solar system best reproduces Mercury-like planets, while outer regions yield Earth-like worlds. This suggests chemical gradients, not catastrophic collisions, shaped both Mercury and similar dense exoplanets.