A recent study suggests that Mercury, the closest planet to the Sun, may have vast diamond deposits buried deep beneath its surface. Published in the journal Nature Communications, this discovery offers new insights into Mercury’s unique geological processes.
Diamonds Beneath Mercury’s Surface
Research led by Yanhao Lin from the Center for High-Pressure Science and Technology Advanced Research in Beijing indicates Mercury’s high carbon content hints at extraordinary geological activity. Lin noted, “Mercury’s extremely high carbon content made me realize that something special probably happened within its interior.” This revelation builds on data from NASA’s Messenger spacecraft, which detected graphite, a form of carbon, on Mercury’s surface.
Formation From A Lava Ocean
Scientists theorize that Mercury formed from the cooling of a hot lava ocean rich in silicate and carbon. As this ocean cooled, metals formed a central core while the remaining magma crystallized into the outer crust and middle mantle. Initially, it was believed that conditions in Mercury’s mantle favored graphite formation. However, a 2019 study suggested that Mercury’s mantle might be deeper than thought, increasing temperature and pressure at the mantle-core boundary, creating conditions suitable for diamond formation.
Simulating Mercury’s Interion
Subjected to pressures of 7 gigapascals (70,000 times Earth’s atmospheric pressure at sea level), these mixtures replicated the extreme conditions deep within Mercury. Computer simulations modeled the temperature and pressure near Mercury’s core-mantle boundary, revealing that diamonds could indeed form under these harsh conditions.
Discovering Diamond Formation and Mining Challenges
The study found that adding sulfur to the chemical mixtures resulted in solidification at higher temperatures, conducive to diamond formation. The models indicated that these diamonds, forming during the solidification of Mercury’s inner core, would float to the core-mantle boundary due to their lower density, potentially forming a layer approximately 15 km (9 miles) thick. Despite this discovery, extracting these diamonds is currently impossible due to Mercury’s extreme temperatures and the depth of nearly 485 km below the surface.
Implications for Mercury’s Magnetic Field
Lin suggested that the presence of diamonds might influence Mercury’s magnetic field by aiding in heat transfer between the mantle and core, leading to temperature differentials and the circulation of liquid iron, which generates a magnetic field. Understanding the presence of diamonds on Mercury could shed light on the planet’s unusual magnetic field, which is much weaker than Earth’s.
This study provides new perspectives on Mercury’s composition and internal processes, offering a glimpse into the planet’s geological history and unique characteristics. While extracting these diamonds is currently unfeasible, their existence could significantly impact our knowledge of planetary science and the dynamic processes shaping our solar system’s innermost planet.
