Chinese scientists have unraveled the mystery behind the unusually cohesive lunar soil retrieved by China's Chang'e-6 mission from the far side of the moon.
The soil's sticky and clumpy characteristics -- which distinguish it from samples collected on the near side of the moon, have captivated researchers since the mission's successful completion in 2024.
This intriguing observation prompted a comprehensive investigation by a research team led by the Institute of Geology and Geophysics under the Chinese Academy of Sciences. Their findings have been published in the latest issue of Nature Astronomy.
To figure out this peculiar feature, the team carried out a series of experiments, including fixed funnel tests and drum tests -- to measure the angle of repose of the Chang'e-6 lunar soil.
This angle serves as a key indicator of the flow behavior of granular materials. Results revealed that the Chang'e-6 soil exhibited a significantly higher angle of repose compared with near-side samples, rendering its flow properties more akin to those of cohesive terrestrial soils.
Researchers found that the soil's cohesiveness partially comes from its texture, which is finer than that on the near side of the moon. The texture of the lunar soil on the near side is similar to sand, but that of the far side is more akin to flour. A handful of sand can easily slip through fingers, whereas flour tends to clump together in the palm.
Additionally, the particles of the lunar soil sample from the far side of the moon are angular and rough. The combination of their fine yet rough characteristics amplifies the effects of forces like static electricity, resulting in the soil being unusually cohesive.
The difference between the qualities of the soil on the moon's near and far sides can be attributed to the space environment they are exposed to.
The far side is more frequently and severely hit by meteorites, and the plagioclase minerals, which constitute mountains on the far side, can easily generate a multitude of fine and angular particles upon impact.
Unlike the near side of the moon, the far side is not shielded by the Earth's magnetic field, resulting in its full exposure to a harsher space environment where there are frequent hits from charged particles, meteoroids, and micro-meteoroids.
These relentless clashes fully break down, melt, churn up, and mix the particles, finally creating the fine and sticky soil found on the far side.
The findings are significant for future exploration, landing, and establishment of bases on the moon's far side.
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.
Chinese scientists decipher mystery of sticky soil on moon's far side
China is charting a course for foreign-invested businesses operating in the country to weather tariff pressures, with expanded trade partnerships, stronger domestic demand and industrial upgrading highlighted as keys to stability by officials and executives commenting on the sidelines of the ongoing "two sessions."
The "two sessions" are the annual meetings of China's supreme organ of state power, the National People's Congress (NPC), and its top political advisory body, the National Committee of the Chinese People's Political Consultative Conference (CPPCC). Both bodies serve five-year terms and hold a plenary session each year.
The fourth session of the 14th NPC and the fourth session of the 14th National Committee of the CPPCC kicked off in Beijing on March 5 and March 4, respectively.
Against this backdrop, global businesses have been grappling with the impact of the United States' unpredictable tariff policy, a challenge that executives say often lies more in uncertainty than in the duties themselves.
"For companies that operate across borders, the uncertainty is often more of a challenge than the tariffs themselves,” said Vaughn Barber, chairman of the China-Australia Chamber of Commerce.
"By being local in China, we obviously are working very hard that we can avoid, hopefully, tariffs going forward. But again, this is only partially true because at the end of the day, it's a global product and certain things simply come from the US, as the aviation industry is a global industry. So to a certain point, there's an element where you cannot really de-risk for, where you can just only work on the fact that the success of aviation is that it is a global industry, and we're asking everybody to recognize that," said Erik Buschmann, Global Senior Vice President of Airbus, and chief operating officer of Airbus China.
Speaking on the sidelines of the NPC session, Commerce Minister Wang Wentao said one key to stabilizing foreign trade is expanding partners, noting that China has 160 major trade partners, of which 51.9 percent are Belt and Road countries.
Wang highlighted the importance of boosting domestic demand, pointing to key areas such as transportation, housekeeping and travel. He also stressed the need to sharpen global competitiveness through technological innovation and industrial upgrading, a message that drew broad recognition from both Chinese and foreign companies
"We see the emphasis on strengthening of demand and consumption, stable economy, technological and industrial upgrading, opening up in services and innovation sectors. Those are all positive messages for business and Australian companies are definitely focused on those," said Barber.
"In terms of high-quality development, we can make technological breakthroughs that will enhance traditional medicine, if we upgrade our resources and technology in this field. China will surely usher in a better spring," said Ruan Hongxian, chairman of the Yixintang Pharmaceutical Group, a large retail chain company based in Kunming, southwest China's Yunnan Province.
China charts course for foreign businesses to weather tariff pressures: executives
