(CNN) – The historic Chandrayaan-3 mission, which made India the fourth country to land on the moon a year ago this Friday, uncovered new evidence supporting a theory about early lunar history.
When the mission landed in the high-latitude southern regions of the Moon, near the lunar south pole, it deployed a small six-wheeled rover called Pragyan, which means wisdom in Sanskrit. The rover was equipped with scientific instruments that allowed it to analyze the particles of the lunar soil and measure the elements found there.
The Pragyan rover made 23 measurements while rolling over a 103-meter region of the lunar surface, located 50 meters from the Chandrayaan-3 landing site, for about 10 days. The rover data marks the first measurements of elements within the lunar soil near the south polar region.
The rover detected a relatively uniform composition made up largely of a rock called ferrous anorthosite, similar to samples taken in the Moon’s equatorial region during the Apollo 16 mission in 1972.
The researchers reported the findings in a study published Wednesday in the academic journal Nature.
Lunar samples are helping scientists solve lingering mysteries about the Moon’s evolution over time, including how it formed during the chaotic early days of the solar system.
The presence of similar rocks in different parts of the Moon provides additional support for the decades-old hypothesis that the Moon was once covered by an ancient magma ocean, the study’s authors point out.
There are many theories about how the Moon formed, but most scientists agree that about 4.5 billion years ago, a Mars-sized object or series of objects collided with Earth, launching enough molten debris into space to create the Moon.
The first lunar samples collected during the Apollo 11 mission in 1969 led researchers to the theory that the Moon was once a molten ball of magma.
The 382 kilograms of lunar rocks and soil returned to Earth by the Apollo missions in the late 1960s and early 1970s refuted ideas that the Moon was a celestial body trapped in Earth’s gravity, or that the Moon formed next to Earth from the same debris. Rock samples indicated that the Moon was created about 60 million years after the solar system began to form, according to NASA.
The magma ocean, probably hundreds to thousands of kilometers deep, persisted for about 100 million years, stated the space agency. As the magma ocean cooled, crystals formed inside it.
Some rocks and minerals, such as ferrous anorthosite, rose to the surface to form the lunar crust and highlands, while other denser, magnesium-rich minerals, such as olivine, sank below the surface, into the mantle, he explained. Noah Petro, NASA project scientist for both the Lunar Reconnaissance Orbiter and the Artemis III mission. Petro was not involved in the new study.
While the lunar crust has an average thickness of about 50 kilometers, the lunar mantle beneath it reaches about 1,350 kilometers deep.
All the minerals and rocks on the Moon have a story to tell about lunar history, Petro said.
When the Pragyan rover carried out its research on the chemical composition of lunar soil, it found a mixture of ferrous anorthosite and other types of rocks, including minerals such as olivine.
Chandrayaan-3’s landing site, called Shiv Shakti Point, was about 350 kilometers from the edge of the South Pole-Aitken basin, considered the oldest crater on the Moon.
The team of researchers believes that an asteroid impact created the basin between 4.2 and 4.3 billion years ago and unearthed magnesium-rich minerals, such as olivine, mixing them with the lunar soil, explained the study’s lead author, Santosh Vadawale, professor from the Ahmedabad Physical Research Laboratory, India.
Researchers continue to investigate the presence of these minerals that likely originated in the lunar mantle to provide more context to the origins and evolution of the Moon, he added.
The mission demonstrates why it is crucial to send spacecraft to different lunar regions to understand the history of the Moon, Vadawale said.
“All previous successful Moon landings have been limited to equatorial and mid-latitude regions,” he said. “Chandrayaan-3 is the first mission to successfully land in the polar regions of the Moon and carry out in-situ analysis. “These new measurements in hitherto unexplored areas further increase confidence in the (lunar magma ocean) hypothesis.”
Next, the Indian lunar exploration program wants to explore the permanently shadowed regions of the lunar poles and return samples for detailed analysis in laboratories on Earth, Vadawale said.
While erosion and tectonic plate movement have erased evidence of how the Earth formed, the Moon remains largely unaltered, aside from impact craters, Petro said.
“Every time we land on the lunar surface, that understanding is anchored to a specific point, a specific location on the surface, which is very useful for testing all the models and hypotheses that we have,” he said. “That magma ocean hypothesis drives much of what we think about the Moon, especially early in its history. “The results from the Chandrayaan-3 rover mission add another data point on the surface.”
Each mission not only adds another piece to the puzzle of understanding the Moon, but also provides insights into how Earth and other rocky planets like Mars formed. Scientists’ understanding of how the Moon formed drives models of how all planets form and change, including planets beyond our solar system, Petro said.
And as more missions are planned to return to the lunar surface, it’s like the gift that multiplies, especially with the prospect of collecting samples from different regions, including the far side of the Moon and the poles.
“Every time we get a new piece of information,” Petro said, “it’s one more embellishment on that gift.”
