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CNN
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As Chinese scientists analyzed soil samples their lunar probe brought back from the Moon, they realized something revolutionary: water and minerals were found in the soil.
The discovery of water on the Moon is nothing new. NASA and Indian probes have spotted what they believe to be water on the Moon’s surface, and Chinese scientists last year discovered water trapped in glass beads scattered across the Moon.
But this latest discovery, scientists say, is the first time water in its molecular form, H2O, has been found in physical samples — and, more importantly, it has been recovered from a part of the moon where they previously thought water in this form could not exist.
Researchers took a close look at samples collected by China’s Chang’e-5 probe, which landed on the lunar surface in 2020, and discovered a “transparent, prismatic, plate-like crystal” — about the width of a human hair — that was actually an “unknown lunar mineral” dubbed ULM-1, according to the study, published July 16 in the journal Nature Astronomy.
ULM-1 crystals (chemical formula (NH4)MgCl3·6H2O) are about 41 percent water, with bits of ammonia that keep those H2O molecules stable despite the moon’s wildly changing temperatures, the study found.
This type of water could be a “potential resource for lunar habitation,” the scientists wrote in their study.
The discovery is the latest in China’s push to become a dominant space power, with far-reaching ambitions including building a research base on the moon. The study was hailed by enthusiastic Chinese social media users, who noted that the space program was a source of national pride.
“The discovery of a hydrated mineral at the Chang’e-5 landing site is fascinating and will further improve our understanding of rock-vapor reactions in the lunar crust and on the lunar surface,” said David A. Kring, a senior scientist at the Lunar and Planetary Institute in Texas, who was not involved in the study.
According to Yuqi Qian, a planetary geologist at the University of Hong Kong who was not involved in the study, three types of water may exist on the moon.
There are water molecules, the compound we know as H2O; its frozen form, ice; and a molecular compound called hydroxyl, a close chemical relative.
Previous findings suggested that water existed on the Moon when volcanoes erupted in the ancient past – and that lunar water came from those volcanoes, meaning it originated inside the Moon and was present since the Moon’s beginning.
But people didn’t always know there was water on the moon, even though scientists theorized about its existence for hundreds of years. Researchers sometimes believed the moon was dry, especially after finding no water in samples collected by NASA’s Apollo and the Soviet Union’s Luna missions.
Only more recently have scientists discovered water, ice, and water molecules located primarily at the dark, cold lunar poles, where the sun doesn’t reach the surface. A recent study also suggested that water or hydroxyl could be trapped in glass beads scattered across the lunar surface, and that solar winds could convert the hydroxyl (chemical formula OH) into water, or H2O.
But the lunar poles are difficult to navigate because of the rocky terrain, making it difficult for humans to extract water. And molecular water is “not stable in other regions of the moon,” vaporizing at lower latitudes where temperatures can exceed 100 degrees Celsius (212 degrees Fahrenheit), Qian said.
This new study changes that.
The samples, retrieved by China’s Chang’e-5 probe, came from a mid-latitude part of the moon, at 43.1 degrees latitude, an area that is normally “not stable for molecular water,” Qian said. Ammonium was found in the samples, which acted as a stabilizer for the water molecules, he said.
This mechanism also supports NASA’s findings from 2020, when its SOFIA telescope detected the signature of water on the lunar surface — though scientists couldn’t verify that finding with physical samples at the time, nor explain exactly how the water remained on the hot surface.
“I think this new discovery, which allows us to extract molecular water directly from lunar soils, has great potential,” Qian said. “I think this is a new mechanism to stabilize molecular water on the lunar surface.”
Kring, of the Lunar and Planetary Institute, cautioned that even though the sample was taken from a mid-latitude area, “it’s not certain that it formed there. Impact processes can redistribute rock on the lunar surface.”
A growing number of countries, including the United States, are considering the strategic and scientific benefits of expanded lunar exploration.
China has made rapid progress in recent years, reflecting leader Xi Jinping’s “eternal dream” of making the country a space power.
In 2013, China became the first country to successfully land a robotic moon landing in nearly four decades. Then, in 2019, it became the first and only country to land on the far side of the moon. Three years later, China completed its latest orbital space station, Tiangong.
And the archipelago has other projects in mind, such as sending astronauts to the Moon by 2030 and building a research base at its south pole.
Understanding how water is stored on the moon is useful, experts previously told CNN, because it could point future lunar astronauts to potential resources that could one day be converted into drinking water or even rocket fuel.
After the latest study, many Weibo users have raised the possibility of growing plants or crops on the moon using molecular water in the soil. But Qian said it is too early to draw such conclusions. Growing anything on the moon would depend on factors such as the abundance of water, which requires more research to confirm.
However, he added, “this new phenomenon, this new mechanism… will open the door to the discovery of new water in this new form.”
Kring also cautioned that the results obtained so far have “no significant implications for the architecture of exploration missions, although they demonstrate that discoveries await those willing and able to explore the Moon.”
China’s rapid progress has caught NASA’s attention. The space agency has not been allowed to work with its Chinese counterparts since 2011, when Congress passed the Wolf Amendment, citing concerns about espionage.
But last August, China opened access to Chang’e-5 samples to the international community.
“We are currently going through the process with our scientists and our lawyers to make sure that the instructions and the safeguards that the Chinese are insisting on … are not a violation of the law, the Wolf Amendment,” NASA Administrator Bill Nelson recently told CNN. “At this point, I don’t see any violations.”
But those problems have locked China out of the International Space Station (ISS), prompting China to build the Tiangong, which has become a competitor to the United States, especially as the ISS prepares to retire in 2031.
These limits on international space collaboration and the rise of China itself have given some Chinese social media users a sense of vindication over the latest discovery — with online comments and state media coverage hailing the advances in the nation’s space program.
“This is a demonstration of our country’s scientific and technological strength!” posted one user on Chinese social media site Weibo, where a hashtag about the discovery has been viewed 35 million times.
Another user thanked the country’s space program, writing: “We are at the forefront of global lunar science research.”
Others on Weibo called for greater cooperation for the benefit of humanity, pointing out that the study was published in an international journal reviewed by experts from various countries.
“We cannot work behind closed doors. It would be better to attract all their scientists to China,” one wrote.
