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The Pragyan rover, launched as part of India’s Chandrayaan-3 mission on July 14 last year, touched down near the lunar south pole on August 23, 2023. It has now found crucial evidence bolstering the claim about the lunar surface being made up of magma.
Pragyan’s landing site on the moon has been named Point Shiv Shakti. Pragyan also searched 23 sites around it in order to collect and test soil samples and measure seismic activity and atmospheric conditions.
The 23 measurements of the rover by the Alpha Particle X-ray Spectrometer (APXS) experiment showed that the moon’s surface was mainly uniform and primarily composed of ferroan anorthosite (FAN), a type of lunar rock. These findings were published by an all-Indian team in the Nature journal on August 21, 2024.
Earlier sensor data collected by the Apollo, Luna and Chang’e 5 missions, from equatorial to mid-latitude regions, showed that the moon’s ‘regolith’ in those areas was also uniform and composed of the same material.
The ‘regolith’ is a layer of rock fragments that covers the exposed surfaces of airless bodies in space, such as the Moon.
This bolsters the claim that the moon’s surface was composed of magma when it was first formed 4.5 billion years ago and lends credence to the Lunar Magma Ocean hypothesis.
This theory posits that the moon was formed out of a giant collision which melted several kilometres of the moon’s surface. This meant that, at its inception, the moon was entirely covered by an ocean of hot magma, which took millions of years to cool and solidify into rocks.
The high presence of anorthosites (FAN), which is a lightweight silica mineral, is also explained by the moon having a liquid, lava crust for the first few million years. This would essentially allow lighter elements such as the anorthosites to stay afloat and the heavier ones to sink to the bottom.
Santosh Vadawale from the Physical Research Laboratory, who is a co-author of the paper which delves into Chandrayaan-3’s recent findings and was part of its mission control team, was quoted as saying that with these recent findings, the theory of evolution of the moon becomes much more robust.
This was first predicted by the Apollo programme, after which several others tested and analysed the moon’s regolith in equatorial and mid-latitude ranges. But data from the Chandrayaan-3 marks the first time that the same could be confirmed for high altitude regions near the lunar south pole.
The mission was the third of the Chandrayaan programme. Its success meant India became the fourth country to successfully land on the moon, after the erstwhile Soviet Union, the United States and China.
India also became the first country to land near the lunar south pole, which had earlier remained unexplored.