The Indian Space Research Organisation’s (ISRO) Chandrayaan-3 mission, which successfully landed on the Moon’s south pole in August 2023, has unearthed compelling data that supports the long-held theory of a ‘magma ocean’ covering the lunar surface in its early stages. This finding, reported in the journal Nature, is based on an analysis of lunar soil measurements and samples collected by the mission’s Pragyan rover.
The Pragyan rover, deployed by the Vikram lander, traversed a 100-meter track on the Moon’s surface, meticulously collecting data at multiple points. The analysis of this data revealed that the lunar soil is consistently composed of a single rock type – ferroan anorthosite, or FAN. Notably, this finding aligns with previous data obtained from the Moon’s equatorial and mid-latitude regions by NASA’s Apollo missions and the Soviet Union’s Luna missions.
The consistency in composition across geographically diverse locations strengthens the ‘magma ocean’ hypothesis, which posits that the Moon’s surface was once completely molten. This hypothesis, widely accepted in the scientific community, explains the formation of the Moon’s crust, mantle, and core.
According to this theory, the Moon was born from a colossal collision between two protoplanets, one of which eventually became Earth. The impact generated immense heat, causing the Moon’s entire mantle to melt into a ‘magma ocean’. As the Moon cooled, less dense FAN floated to the surface, forming the crust, while heavier minerals sank to create the mantle beneath.
While the data from Chandrayaan-3 strongly supports the ‘magma ocean’ hypothesis, the analysis did identify the presence of magnesium in the lunar soil. This detection, while intriguing, could potentially challenge the hypothesis, as some studies based on recent re-analysis of Apollo samples have questioned its validity. However, the authors of the Nature study emphasize that the consistency of the soil composition and geological context overwhelmingly support the ‘magma ocean’ theory despite the presence of magnesium.
The Pragyan rover’s Alpha Particle X-ray Spectrometer (APXS) played a crucial role in collecting data about the elements present in the soil around the Chandrayaan-3 landing site, aptly named ‘Shiv Shakti Point’. This data, combined with the analysis of lunar soil samples, provides valuable insights into the Moon’s formation and early evolution, shedding light on the celestial body’s intriguing history.
