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This photo taken on July 9, 2025 shows a press conference held by the Chinese Academy of Sciences (CAS) in Beijing, capital of China. A series of research findings by Chinese scientists on the samples collected by the Chang’e-6 mission from the moon’s far side have unveiled the volcanic activity, ancient magnetic field, water content and geochemical characteristics of the moon mantle, shedding the first light on the evolutionary history of its dark side. Four studies by the research teams from the Institute of Geology and Geophysics (IGG), the National Astronomical Observatories, both under the Chinese Academy of Sciences (CAS), Nanjing University, and other institutions were published in the latest issue of Nature. As the moon’s revolution cycle is the same as its rotation cycle, the same side always faces Earth. The other face, most of which cannot be seen from Earth, is called the far, or dark, side of the moon. This term doesn’t refer to visible darkness, but rather the mystery shrouding the moon’s largely unexplored terrain. (Xinhua/Jin Liwang)

BEIJING, July 9 (Xinhua) — A series of research findings by Chinese scientists on the samples collected by the Chang’e-6 mission from the moon’s far side have unveiled the volcanic activity, ancient magnetic field, water content and geochemical characteristics of the moon mantle, shedding the first light on the evolutionary history of its dark side.

Four studies by the research teams from the Institute of Geology and Geophysics (IGG), the National Astronomical Observatories, both under the Chinese Academy of Sciences (CAS), Nanjing University, and other institutions were published in the latest issue of Nature.

As the moon’s revolution cycle is the same as its rotation cycle, the same side always faces Earth. The other face, most of which cannot be seen from Earth, is called the far, or dark, side of the moon. This term doesn’t refer to visible darkness, but rather the mystery shrouding the moon’s largely unexplored terrain.

The moon’s near and far sides exhibit significant differences in morphology, composition, crustal thickness and magmatic activities. However, the mechanisms behind these disparities remain unresolved, representing a key issue in lunar science. Previously, scientific understanding of the far side relied primarily on remote sensing studies, scientists say.

In 2024, Chang’e-6 made history by bringing 1,935.3 grams of lunar far-side samples back to Earth. These samples were collected from the South Pole-Aitken (SPA) Basin, the largest, deepest and oldest basin on the moon, which provided a rare opportunity to clarify the compositional differences between the near and far sides and to unravel the long-standing mystery of their asymmetry.

“The SPA Basin is one of the moon’s three major tectonic units, measuring approximately 2,500 kilometers in diameter. The energy from the impact that formed this crater is estimated to be 1 trillion times greater than that of an atomic bomb explosion. Yet, the exact influence of such a massive collision on the moon’s evolution has remained an unsolved mystery,” Wu Fuyuan, an academician of CAS and a leading researcher with the IGG, said at a CAS press conference on Wednesday.

The four papers published in Nature systematically reveal, for the first time, the effects of this colossal impact, which is the core highlight of these findings, said Wu.

Over the past year, Chinese scientists have achieved multiple pioneering breakthroughs through the study of the Chang’e-6 samples.

They found the evidence of volcanic activity on the moon’s far side approximately 4.2 billion and 2.8 billion years ago, indicating such activity had persisted for at least 1.4 billion years.

For the first time, scientists obtained the ancient magnetic field information from the far side of the moon, revealing a possible rebound in the moon’s magnetic field intensity around 2.8 billion years ago. This discovery indicates the presence of fluctuations in the driven power of the lunar dynamo.

Scientists have found that the water content in the lunar far-side mantle is significantly lower than that of the near side, indicating a significant difference in water distribution between the two hemispheres.

“We found that the mantle source of basalt from the SPA basin is extremely depleted in incompatible elements, which are commonly used to reveal the geological processes that rocks have undergone,” said Yang Wei, a researcher with IGG.

This depletion could mean either the original lunar mantle was very low in the incompatible elements, or the massive impact event melted the rocks and carried these elements away. This discovery underscores the profound influence of large impacts on the evolution of the moon’s deep interior, Yang said.

“The new discovery marks humanity’s first direct access to key evidence of the deep interior material properties on the far side of the moon. It provides us with unique information to understand how the moon’s early interior became layered, cooled and evolved, representing a crucial step toward unraveling the mystery behind the dramatic differences between the lunar near and far sides,” said Li Chunlai, a researcher at the National Astronomical Observatories of CAS and deputy chief designer of the Chang’e-6 mission.

Additionally, Chinese scientists have made other discoveries. They unveiled the physical, mineralogical and geochemical characteristics of the Chang’e-6 lunar samples.

Meanwhile, Chinese scientists precisely determined for the first time that the SPA Basin formed 4.25 billion years ago, providing humanity with a more accurate anchor point for studying the history of large-scale impacts in the early solar system.

Mahesh Anand, a professor at the Open University in the UK, said, “We have had samples from the moon for over 50 years, samples collected by the Apollo and Luna missions. And we have many lunar meteorites.”

“But there are lots of new findings that are coming out based on the work that has been done on Chang’e-6 samples that are actually turning many of the well established hypotheses and theories in the field of lunar science upside down, necessitating reexamination of many of those theories,” Anand said.

He Hongping, vice president of CAS, said that upon receiving the Chang’e-6 lunar samples, CAS has placed high priority on related research efforts, and has yielded a series of high-level research achievements.

Guan Feng, director of the Lunar Exploration and Space Engineering Center of the China National Space Administration, expressed the hope that the comprehensive development of space science, space technology and space applications will be further promoted, urging more scientists to make use of the extraterrestrial samples and scientific data obtained from China’s lunar and deep space exploration missions to achieve more results and make more discoveries.

Previously, Chinese scientists analyzed the samples collected by the Chang’e-5 mission from the moon’s near side, and found evidence of young volcanic activity dating back just 2 billion years, extending the moon’s volcanic timeline by 1 billion years. This discovery was hailed by international peers as changing humanity’s understanding of lunar evolution.

The success of China’s lunar exploration program is a prime example of the deep integration between science and engineering, said Li of the National Astronomical Observatories.

Ouyang Ziyuan (C), an academician with the Chinese Academy of Sciences (CAS), speaks during a CAS press conference in Beijing, capital of China, on July 9, 2025. A series of research findings by Chinese scientists on the samples collected by the Chang’e-6 mission from the moon’s far side have unveiled the volcanic activity, ancient magnetic field, water content and geochemical characteristics of the moon mantle, shedding the first light on the evolutionary history of its dark side.Four studies by the research teams from the Institute of Geology and Geophysics (IGG), the National Astronomical Observatories, both under the Chinese Academy of Sciences (CAS), Nanjing University, and other institutions were published in the latest issue of Nature. As the moon’s revolution cycle is the same as its rotation cycle, the same side always faces Earth. The other face, most of which cannot be seen from Earth, is called the far, or dark, side of the moon. This term doesn’t refer to visible darkness, but rather the mystery shrouding the moon’s largely unexplored terrain. (Xinhua/Jin Liwang)

Hui Hejiu, professor of Nanjing University, speaks during a press conference held by the Chinese Academy of Sciences (CAS) in Beijing, capital of China, on July 9, 2025. A series of research findings by Chinese scientists on the samples collected by the Chang’e-6 mission from the moon’s far side have unveiled the volcanic activity, ancient magnetic field, water content and geochemical characteristics of the moon mantle, shedding the first light on the evolutionary history of its dark side. Four studies by the research teams from the Institute of Geology and Geophysics (IGG), the National Astronomical Observatories, both under the Chinese Academy of Sciences (CAS), Nanjing University, and other institutions were published in the latest issue of Nature. As the moon’s revolution cycle is the same as its rotation cycle, the same side always faces Earth. The other face, most of which cannot be seen from Earth, is called the far, or dark, side of the moon. This term doesn’t refer to visible darkness, but rather the mystery shrouding the moon’s largely unexplored terrain. (Xinhua/Jin Liwang)

This photo taken on July 9, 2025 shows a press conference held by the Chinese Academy of Sciences (CAS) in Beijing, capital of China. A series of research findings by Chinese scientists on the samples collected by the Chang’e-6 mission from the moon’s far side have unveiled the volcanic activity, ancient magnetic field, water content and geochemical characteristics of the moon mantle, shedding the first light on the evolutionary history of its dark side. Four studies by the research teams from the Institute of Geology and Geophysics (IGG), the National Astronomical Observatories, both under the Chinese Academy of Sciences (CAS), Nanjing University, and other institutions were published in the latest issue of Nature. As the moon’s revolution cycle is the same as its rotation cycle, the same side always faces Earth. The other face, most of which cannot be seen from Earth, is called the far, or dark, side of the moon. This term doesn’t refer to visible darkness, but rather the mystery shrouding the moon’s largely unexplored terrain. (Xinhua/Jin Liwang)

Ouyang Ziyuan (2nd R), an academician with the Chinese Academy of Sciences (CAS), speaks during a CAS press conference in Beijing, capital of China, on July 9, 2025. A series of research findings by Chinese scientists on the samples collected by the Chang’e-6 mission from the moon’s far side have unveiled the volcanic activity, ancient magnetic field, water content and geochemical characteristics of the moon mantle, shedding the first light on the evolutionary history of its dark side. Four studies by the research teams from the Institute of Geology and Geophysics (IGG), the National Astronomical Observatories, both under the Chinese Academy of Sciences (CAS), Nanjing University, and other institutions were published in the latest issue of Nature. As the moon’s revolution cycle is the same as its rotation cycle, the same side always faces Earth. The other face, most of which cannot be seen from Earth, is called the far, or dark, side of the moon. This term doesn’t refer to visible darkness, but rather the mystery shrouding the moon’s largely unexplored terrain. (Xinhua/Jin Liwang)

Wu Fuyuan, an academician of the Chinese Academy of Sciences (CAS) and a leading researcher with the Institute of Geology and Geophysics (IGG), speaks during a CAS press conference in Beijing, capital of China, on July 9, 2025. A series of research findings by Chinese scientists on the samples collected by the Chang’e-6 mission from the moon’s far side have unveiled the volcanic activity, ancient magnetic field, water content and geochemical characteristics of the moon mantle, shedding the first light on the evolutionary history of its dark side. Four studies by the research teams from the Institute of Geology and Geophysics (IGG), the National Astronomical Observatories, both under the Chinese Academy of Sciences (CAS), Nanjing University, and other institutions were published in the latest issue of Nature. As the moon’s revolution cycle is the same as its rotation cycle, the same side always faces Earth. The other face, most of which cannot be seen from Earth, is called the far, or dark, side of the moon. This term doesn’t refer to visible darkness, but rather the mystery shrouding the moon’s largely unexplored terrain. (Xinhua/Jin Liwang)

Li Chunlai, a researcher with the National Astronomical Observatories of the Chinese Academy of Sciences (CAS) and deputy chief designer of the Chang’e-6 mission, speaks during a CAS press conference in Beijing, capital of China, on July 9, 2025. A series of research findings by Chinese scientists on the samples collected by the Chang’e-6 mission from the moon’s far side have unveiled the volcanic activity, ancient magnetic field, water content and geochemical characteristics of the moon mantle, shedding the first light on the evolutionary history of its dark side. Four studies by the research teams from the Institute of Geology and Geophysics (IGG), the National Astronomical Observatories, both under the Chinese Academy of Sciences (CAS), Nanjing University, and other institutions were published in the latest issue of Nature. As the moon’s revolution cycle is the same as its rotation cycle, the same side always faces Earth. The other face, most of which cannot be seen from Earth, is called the far, or dark, side of the moon. This term doesn’t refer to visible darkness, but rather the mystery shrouding the moon’s largely unexplored terrain. (Xinhua/Jin Liwang)

This image created by Chinese researchers shows the moon’s far side. A series of research findings by Chinese scientists on the samples collected by the Chang’e-6 mission from the moon’s far side have unveiled the volcanic activity, ancient magnetic field, water content and geochemical characteristics of the moon mantle, shedding the first light on the evolutionary history of its dark side. Four studies by the research teams from the Institute of Geology and Geophysics (IGG), the National Astronomical Observatories, both under the Chinese Academy of Sciences (CAS), Nanjing University, and other institutions were published in the latest issue of Nature. As the moon’s revolution cycle is the same as its rotation cycle, the same side always faces Earth. The other face, most of which cannot be seen from Earth, is called the far, or dark, side of the moon. This term doesn’t refer to visible darkness, but rather the mystery shrouding the moon’s largely unexplored terrain. (CAS/Handout via Xinhua)

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Almost two-thirds of the world’s population is affected by the monsoon – the annual arrival of intense rains in areas north and south of the Equator. These drenching rains tend to arrive during each hemisphere’s summer.

The East Asian monsoon north of the equator is the best known and best studied, because it affects the largest land area and the most people. But the southern Indo-Australian monsoon is vitally important to northern Australia, Indonesia and Papua New Guinea. To date, it has been studied much less.

To help fill this gap in knowledge, we analysed deep sediment from an unusual lagoon near Darwin in northern Australia. We looked at ancient pollen and chemical isotopes (different versions of the same chemical element) to look about 150,000 years back in time and glimpse changes to the monsoon. When types of pollen change, it tells us the monsoon has changed. Drier conditions favour the emergence of grasslands, while wetter climates favour forests.

Our new research suggests as the world gets hotter, the Indo-Australian monsoon will intensify and northern Australia will get wetter. This finding is consistent with research suggesting the East Asian monsoon could weaken, threatening agriculture and nature in heavily populated countries.

The past held in a single lagoon

To examine how monsoons change over time, researchers drill sediment cores to track changes in pollen and chemical isotopes. For example, changes in hydrogen isotopes indicate changes in the intensity of the monsoon rain.

The problem is, these cores have to come from long-undisturbed lake sediments, because such places provide a continuous record of change.

To reconstruct past changes in monsoon patterns, undisturbed sediments have to be sampled carefully by extracting a thin “core” from the bottom sediments. Once researchers have this precious core, they can examine the changing proportions of pollen, chemical isotopes and other properties. The deeper you drill the core, the farther back in time you can look.

These exacting requirements are one reason the Indo-Australian monsoon is not as well understood as its northern cousin.

Fortunately, we have found one place which has kept a detailed environmental record over a long period: Girraween Lagoon on the outskirts of Darwin in the Northern Territory.

This lagoon was created after a sinkhole formed more than 200,000 years ago. It has contained permanent water ever since, and is slowly filling with sediment and pollen blown in from the surrounding landscape.

The 18-metre core from Girraween’s sediments gave us a 150,000-year record of environmental change in Australia’s northern savannahs.

Dipping into the past

If you walk around Girraween Lagoon today, you’ll see a tall and dense tree canopy with a thick grass understory in the wet season. But it hasn’t always been that way.

During the last ice age 20,000–30,000 years ago, the sea level was much lower and the polar ice caps much larger. As a result, the lagoon was more than 300 kilometres from the coast. At that time, the lagoon was surrounded by an open, grassy savannah with fewer, shorter trees.

About 115,000 years ago (and again 90,000 years ago), Australia was dotted with gigantic inland “megalakes”. At those times, the lagoon expanded into a large, shallow lake surrounded by lush monsoon forest, with almost no grass.

At times, tree cover changed radically. In fact, over one 3,000-year period, the percentage of tree pollen soared from 15% to 95%. That suggests a sweeping change from grassland to dense forest – meaning a switch from drier to wetter climate at a rate too fast to be explained by changes in Earth’s orbit.

Some of these changes are linked to the shifting distance between coastline and lagoon as well as predictable variation in how much solar energy reaches Earth.

A connection to the North Atlantic

Huge ice sheets covered large areas of the Northern Hemisphere during previous ice ages.

Remarkably, the evidence of their melting at the end of previous ice age was there in the sediment core from Girraween Lagoon.

When glacial ice melts rapidly, huge volumes of fresh water flood into the North Atlantic. These rapid pulses are known as Heinrich events. These pulses can shut down the warm Gulf Stream current up the east coast of North America. As a result, the Northern Hemisphere cools and the Southern Hemisphere warms.

Over the last 150,000 years, there have been 14 of these events. We could see evidence of them in the sediment cores. Every gush of fresh water in the Atlantic triggered higher rainfall over northern Australia because of the buildup of heat in the Southern Hemisphere as the Gulf Stream slowed.

What does this mean for the monsoon?

All this suggests the Indo-Australian monsoon will get more intense as the world gets hotter and more ice melts.

That would mean a wetter northern Australia. It could also bring more rainfall to other Australian regions, and neighbouring countries. At this stage, it’s too uncertain to predict what an intensifying monsoon would do to the southern parts of Australia.

We might already be seeing this shift. Weather records since the 1960s show northern Australia getting steadily wetter, and less rain in Australia’s southeast and southwest.

What would this mean for people? Australia’s tropical north is not densely populated, which would reduce the human impact of an intensifying monsoon.

But while our research suggests the Indo-Australian monsoon strengthens during Heinrich events, earlier research has shown the East Asian and other Northern Hemisphere monsoons will weaken. Without reliable monsoonal rains, food and water supplies for billions of people could be at risk.