There was once an ancient ocean filled with magma on the moon, scientists say

There was once a magma-filled ocean on the south pole of the moon, scientists recently discovered after analyzing lunar soil that revealed ancient information about the moon's origin.

The study of soil taken from a less-studied region of the moon suggests the presence of remnants of a former ocean of magma, according to a study published Wednesday in Nature.

The researchers analyzed lunar soil extracted from high-latitude regions on the southern portion of the moon -- taken as part of the Chandrayaan-3 mission when India’s Vikram lander module made a historic touchdown near the south pole of the moon in August 2023. The mission is the southern-most landing that has ever taken place on the moon -- a difficult feat considering the lack of sunlight, which can create visibility and communication issues, Anil Bhardwaj, director of Physical Research Laboratory in Ahmedabad and co-author of the study, told ABC News. Most lunar landings, especially human landings, have taken place in the equatorial or low-latitude regions.

The mission embarked the use of new technology -- a particle access spectrometer -- an instrument aboard the rover that was able to make observations and collect data very close to the lunar surface, M. Shanmugam, the lead engineer of the alpha particle X-ray spectrometer at the Physical Research Laboratory in Ahmedabad, told ABC News.

The composition of the soil found on Vikram’s landing site is consistent with an ancient magma ocean, the authors conclude.

When analyzing the soil, the researchers found a relatively uniform elemental composition among 23 measurements at various spots along the lunar surface, primarily containing the rock-type ferroan anorthosite. The spectrum of elements also included all of the major and minor elements of the presence of magma, including sodium, aluminum, magnesium, carbon, silicon, sulfur, potassium, iron, titanium, chromium and manganese, Bhardwaj said.

The moon is believed to have formed after a body the size of Mars struck Earth about 4.24 billion years ago, Bhardwaj said. The material that formed as a result of the volatile impact was likely magma that was thrown into space that remained within the Earth's gravitational pull and eventually began forming a planetary-mass object.

The magma ocean is likely to have existed for tens to hundred million years, Santosh Vadawale, a professor in the Physical Research Laboratory and lead author of the study, told ABC News.

Researchers believed the magma disappeared as the moon cooled throughout its formation, hypothesizing that, less dense ferroan anorthosite floated to the lunar surface while heavier minerals sank to form the mantle during the cool-down -- forming the lunar highlands as a result of the floatation of lighter anorthositic rock.

Previous research into the Moon’s geology has primarily relied on samples taken by missions to lunar mid-latitudes, such as the Apollo program, giving scientists a more nuanced look into the history of the moon's formation, according to the paper.

While the lunar magma ocean hypothesis has existed for decades, ever since the Apollo mission placed humans on the moon in 1969, the new research has allowed researchers to confirm the evolutionary history of the moon from billions of years ago, Vadawale said.

"Our next mission, we would like to try to go as close as possible to poles, where there are these permanently shadowed regions where there is water is supposed to be there," he said.