Scientists Find 2.18×10^18-kg Mass Beneath Moon's 2,000-km South Pole-Aitken Basin
Updated
Updated · The Brighter Side of News · Jun 18
Scientists Find 2.18×10^18-kg Mass Beneath Moon's 2,000-km South Pole-Aitken Basin
1 articles · Updated · The Brighter Side of News · Jun 18
Summary
Gravity and topography analysis revealed a dense underground structure beneath the Moon’s South Pole-Aitken basin, with at least 2.18 × 10^18 kilograms of excess mass buried to depths of 300 kilometers or more.
NASA’s GRAIL gravity data and LOLA topography measurements showed the anomaly is heavy enough to depress the basin floor by about 1 to 2 kilometers, making buried dense material a better explanation than earlier impact-melt contraction theories.
Researchers say the mass could be iron-nickel metal from the asteroid that formed the basin 3.9 to 4.3 billion years ago, or dense oxide-rich material left from the Moon’s early magma ocean; the anomaly’s 400-kilometer offset from the basin center complicates both ideas.
Its apparent survival for billions of years suggests the lunar lower mantle stayed cool and rigid, with viscosity of at least 8 × 10^21 pascal-seconds, preserving one of the solar system’s clearest records of giant impacts and boosting the basin’s value for future missions.
Is the Moon's giant buried anomaly the metal heart of an asteroid or a relic of its fiery birth?
What secrets about Earth’s own formation are hidden deep inside the Moon’s far side?
The South Pole-Aitken Basin Mass Anomaly: Latest Discoveries, Competing Origins, and Implications for Lunar Science (2025–2026)
Overview
Asteroid impacts have shaped the Moon’s surface since its formation, creating vast craters and basins like the South Pole-Aitken (SPA) basin. Ongoing research, especially from 2025 to 2026, focuses on understanding how these enormous impacts affected not just the surface but also the Moon’s deep interior. Studies of the SPA basin are transforming our knowledge of the Moon’s crust-mantle structure, the timing and effects of major impacts, and the nature of the lunar mantle. This research also helps establish a broader timeline of lunar impacts, offering crucial insights into the Moon’s history and planetary evolution.