(CNN) – When Chinese scientists analyzed soil samples brought back from the Moon by their lunar probe, they noticed something revolutionary: there was water along with minerals in the soil.
Finding water on the Moon is, in itself, nothing new. NASA and Indian spacecraft have detected what they believe to be water on the lunar surface, and Chinese scientists last year found water trapped in glass beads scattered across the Moon.
But this latest discovery, according to scientists, is the first time that water in its molecular form, H2O, has been found in physical samples and, importantly, in a part of the Moon where it was previously thought water in that form could not exist.
Researchers closely inspected samples collected by China’s Chang’e-5 probe, which landed on the lunar surface in 2020, and found a “plate-like prismatic transparent 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.
According to the study, the crystals of ULM-1, whose chemical formula is (NH4)MgCl3-6H2O, are composed of 41% water, with bits of ammonia that keep the H2O molecules stable despite the sudden changes in temperature on the Moon.
This type of water could be a potential “resource for lunar habitability,” the scientists write in their study.
The discovery is the latest in China's quest to become a dominant space powerwith ambitions as ambitious as building a research base on the Moon. The study was greeted with enthusiasm by Chinese social media users, who pointed to the space program as a source of national pride.
“The discovery of a hydrated mineral at the Chang'e-5 landing site is exciting and will 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.
There are three types of water that could exist on the Moon, according to Yuqi Qian, a planetary geologist at the University of Hong Kong who was not involved in the study.
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 discoveries suggested that water had existed on the Moon when volcanoes erupted in the distant past, and that lunar water came from those volcanoes, meaning it came from the Moon's interior and has been present since the earliest times of its existence.
But it was not always known that there was water on the Moon, although scientists theorized about their existence for hundreds of years. Researchers sometimes believed the Moon was dry, especially after failing to find water in samples collected by NASA's Apollo and Soviet Luna missions.
Only in more recent years have scientists found water, ice and water molecules located mostly at the dark, cold lunar poles, where sunlight does not reach. A recent study has also suggested that water or hydroxyl may be trapped in glass beads scattered across the lunar surface, and that solar winds could transform the hydroxyl (chemical formula OH) to form water, or H2O.
But the lunar poles are difficult to navigate due to rocky terrain, making them difficult places for humans to extract water. In addition, molecular water “is not stable in other regions of the Moon” as it evaporates at lower latitudes, where temperatures can exceed 100 degrees Celsius, Qian explains.
This new study changes this situation.
The samples, collected 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 water molecules, he said.
This mechanism also corroborates NASA's findings from 2020, when its SOFIA telescope detected the signature of water on the lunar surface, although scientists were unable to verify this finding with physical samples at the time, nor explain exactly how water remained on the warm surface.
“I think this new discovery that we can extract molecular water directly from lunar soil has great potential,” Qian said. “I think this is a new mechanism to make molecular water stable on the lunar surface.”
Kring, of the Lunar and Planetary Institute, cautioned that although the sample was collected in a mid-latitude area, “it was not clear whether it formed there. Impact processes can redistribute rock across the lunar surface.”
There are more and more countries, among them the United Stateswho are interested in the strategic and scientific benefits of further lunar exploration.
China has carried out rapid progress in recent yearsa reflection of leader Xi Jinping’s “eternal dream” of turning the country into a space power.
In 2013, China became the first country to achieve a robotic lunar 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 last orbital space station, the Tiangong.
And it has more plans, with the aim of landing astronauts on the moon by 2030 and building a research base at its south pole.
Understanding how water is stored on the Moon is useful, as experts explained to CNNbecause it could indicate to future lunar astronauts possible resources that could one day be turned into drinking water or even rocket fuel.
Following the latest study, many Weibo users raised the possibility of growing plants or crops on the Moon using molecular water found in the soil. But, according to Qian, 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 further research to confirm.
However, he added, “this new phenomenon, this new mechanism… will open the door to (finding) water in this new form.”
China successfully launches Chang'E-6 lunar probe
Kring also cautioned that the findings so far “have no significant implications for exploration mission architectures, but demonstrate that discoveries await those willing and able to explore the Moon.”
China's rapid advances have 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 up access to samples from Chang'e-5 to the international community.
“We’re going through the process right now with our scientists and our attorneys to make sure that the instructions and the guardrails that the Chinese are insisting on… are not a violation of the law, of the Wolf Amendment,” NASA Administrator Bill Nelson recently told CNN. “As of this moment, I don’t see any violation.”
However, these issues have prevented China from accessing the International Space Station (ISS), which has fueled its efforts to build Tiangong, which has become a challenge for the United States, especially as the ISS prepares to retire in 2031.
These limits on their international space collaboration, and China's own rise, have left some Chinese social media users feeling vindicated by the latest discovery, with online comments and state media coverage praising the advances of the national space program.
“It is a demonstration of our country’s scientific and technological strength,” wrote 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: “We are at the forefront of the world in lunar scientific research.”
Others on Weibo urged greater cooperation for the benefit of humanity, noting that the study was published in an international peer-reviewed journal from multiple nations.
“We cannot work behind closed doors: the best thing would be to attract all its scientists to China,” wrote one.
