Emily Chan
At one point in time, an ocean of molten rock covered the moon, according to data from India’s recent Chandrayaan-3 mission. Scientists conducted an analysis of geological samples that were gathered during the mission to reach this conclusion.
On August 23, 2023, a lander known as Vikram touched down on the moon’s surface. Once Vikram had made a safe landing, controllers deployed Pragyan, a rover that had been stowed on Vikram, to explore the site.
The location where Vikram had arrived was further south than any other landing craft that had ever been on the moon. Pragyan found that the lunar soil, or regolith, in the area was fairly consistent. The regolith mostly consisted of a type of white rock called ferroan anorthosite.
According to the scientists, the chemical composition of the regolith from the lunar south pole is in between the samples from two spots in the moon’s equatorial region. The previous two samples were collected by U.S. astronauts on the Apollo 16 flight in 1972 and during the Soviet Union’s robotic Luna-20 mission that same year.
The chemical composition of all these samples is similar despite coming from distances far away from each other on the moon. As a result, the finding supports the idea that a magma ocean covered the moon early on in its history.
It is thought that the moon was formed after a planet the size of Mars collided with Earth. The collision caused rock to eject from the planet and become Earth’s moon. The magma ocean likely developed tens or hundreds of millions of years after the moon’s formation.
As the magma ocean cooled and crystalized, it led to the eventual emergence of ferroan anorthosite rock, which makes up the moon’s crust.
All three missions landed in the lunar highland regions, which partially represent the ancient lunar crust. So, the researchers were able to compare the samples and test their prediction that the moon was once covered in an ocean of liquid rock.
The magma ocean theory first came about after the Apollo 11 mission returned with its samples. That mission landed in an area with mostly dark basaltic rock. However, fragments of white rock were also present in the Apollo 11 soils. They were given the name ferroan anorthosite.
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