New simulations suggest that a 9-mile-thick layer of diamonds could be lurking deep below Mercury’s surface. While mining these diamonds is not feasible, this discovery may help explain some of the planet’s biggest mysteries.
Study reveals clues about mercury’s composition and magnetic field
The study, published in the journal Nature Communications, delves into Mercury’s composition and its peculiar magnetic field. Unlike Earth’s robust magnetic field, Mercury’s is much weaker, which is unexpected for such a small and geologically inactive planet. Additionally, rare dark surface patches, identified as graphite by NASA’s Messenger mission, have intrigued scientists.
High carbon content sparks scientific curiosity
Co-author Yanhao Lin, a staff scientist at the Center for High-Pressure Science and Technology Advanced Research in Beijing, explained that Mercury’s high carbon content piqued scientific interest. “The extremely high carbon content of Mercury made me realize that something special probably happened within its interior,” Lin said.
Diamond formation process on mercury
Despite Mercury’s oddities, scientists believe it formed similarly to other terrestrial planets, cooling from a hot magma ocean. Mercury’s ocean contained silicate and carbon, with metals coagulating to form a central core as the remaining magma crystallized into the middle mantle and outer crust.
Researchers initially thought the mantle’s temperature and pressure were sufficient only to form graphite, which floated above the surface due to its lighter weight. However, a 2019 study revealed that Mercury’s mantle was 80 miles (50 kilometers) deeper than previously believed. This increased depth likely raised the temperature and pressure at the mantle-core boundary, creating conditions for carbon to crystallize into diamonds.
Exploring diamond formation with chemical simulations
To investigate this possibility, a team of Belgian and Chinese researchers, including Lin, created chemical mixtures containing iron, silica, and carbon. These mixtures, akin to certain meteorites, are believed to resemble the magma ocean of infant Mercury.
The study’s findings provide a tantalizing glimpse into the complex processes that may have shaped Mercury’s interior, potentially revealing a hidden world of diamonds beneath its surface.