Scientists find water trapped in ‘glass droplets’ on the Moon’s surface

Trillions of kilograms of water are scattered across the Moon, trapped in tiny “glass droplets” that would have formed when asteroids collided with the Moon’s surface, according to new research.

The findings, presented in a study published Monday in the journal Nature Geoscience, were pieced together by scientists in China who analyzed the first samples of lunar soil to be returned to Earth since the 1970s.

The research points to the answer to a question that scientists have been asking for years as they try to understand exactly how water is stored on the Moon – particularly in the regions outside the lunar poles, where ice may exist in greater abundance.

Essentially, the study fills in some gaps in a theory about the lunar water cycle.

To sustain a water cycle on the Moon’s surface, there must be a hydrated layer (reservoir) deep in the lunar lands, according to the study’s authors. “However, finding such a reservoir seemed elusive, despite several studies having investigated the inventory of water in fine grains of minerals in lunar soil.”

The researchers decided to identify a potential reservoir of water by investigating the glass droplets formed during asteroid impacts. And the team found the small objects with substantial amounts of water.

A reading of the study

The lunar soil sample analyzed for this study was collected by China’s Chang’e-5 mission, which made a soft landing on the Earth-facing northwest corner of the Moon and carried regolith samples back home in 2020.

From these samples, researchers at various institutions in China, including Nanjing University and the Chinese Academy of Sciences, handpicked 150 grains to study, ranging in size from about 50 micrometers – or the width of a human hair. – to about 1 millimeter.

The theory proposed by this latest research is that these glass droplets, formed in ancient times, may have been imbued with water when hit by the solar winds, which transport hydrogen and oxygen from the sun’s atmosphere through the solar system. In fact, there could be over 600 trillion pounds of water stored on the Moon.

“We have found a new mechanism, in which hydrogen from the solar wind can diffuse into glass droplets, and thus we have identified a new water reservoir on the Moon,” said Hejiu Hui, one of the study’s co-authors and a researcher at Nanjing University, by email. “By contrast, impact glass droplets are distributed in regolith globally on the Moon. Therefore, impact glass droplets can be replenished with water on the surface of the Moon and can sustain the water cycle on the lunar surface.”

The drops can be replenished with water every few years, the study suggested.

The findings build on NASA research that suggests water is present on the sunlit side of the moon. Scientists have been looking for more information about how this water was stored.

NASA did not immediately respond to a request for comment on this study. The space agency has not been allowed to work with its Chinese counterparts since 2011, when Congress passed the Wolf Amendment.

Understanding how water is stored on the Moon is useful, Hui noted, because it could point future lunar astronauts to potential resources that could one day be converted into drinking water or even rocket fuel.

“This water can be released simply by heating these glass beads,” Hui said.

changing perspective

David Kring, principal scientist at the Lunar and Planetary Institute in Houston, said this research gives scientists new insight into how water might be stored on the moon, particularly in locations similar to the Chang’e 5 mission landing site on the near side. from the moon. He was not involved in the study.

“This is important for the scientific discussion of lunar water cycles on the moon,” he noted.

But, Kring said, there are probably better places for astronauts to collect water for practical purposes, “which is why we’re interested in the lunar poles.”

Scientists have theorized that there may be large deposits of water ice at the moon’s poles as far back as the Apollo era. And NASA plans to send astronauts to explore the area as part of its Artemis program, which aims to send humans to the lunar south pole later this decade.

“I think the international interest in exploring the Moon will fuel everyone’s interest,” Kring said. “I can’t wait until we have Artemis astronauts in the lunar south polar region in two to three years.”