Scientists have discovered water inside tiny beads of glass scattered across the moon by studying lunar soil brought back by China's Chang'e-5 spacecraft.

The revelations were made in a study titled "A solar wind-derived water reservoir on the Moon hosted by impact glass beads," published in the journal Nature Geoscience on Monday.

Led by the Chinese Academy of Sciences, the study suggests that "impact glass beads in lunar soils are a prime water reservoir candidate able to drive the lunar surface water cycle."

Glass beads are formed by tiny meteorites that bombard the surface of the moon. The heat of the impact melts the soil and rocks on the lunar surface, which cools into round glass beads around the width of a strand of hair.

Scientists analyzed 117 glass beads which were scooped up by the Chang'e-5 spacecraft and selected 32 homogeneous impact glass beads for further detailed analysis. They found an average water content of 0.05 percent in the glass beads, the Science and Technology Daily reported.

"That's equivalent to half a kilogram of water inside a tonne of impacting glass beads, more than we previously thought," Hui Hejiu, co-corresponding author of the study, told Science and Technology Daily.

"The water in the glass beads is not that in the usual sense, but hydrogen present there, which can be converted into water that we can use through a certain reaction," said Hui.

As well as finding water in the beads, the scientists detected "a telltale signature of the sun," Mahesh Anand, a co-author of the study, told AFP.

Investigating further, they determined that the hydrogen necessary to make up the water was coming from solar wind, which sweeps charged particles across the solar system.

Oxygen, the other ingredient of water, makes up nearly half of the moon, though it is trapped in rocks and minerals.

This means that solar wind could be equally contributing to water on other bodies in the solar system lacking an atmosphere, such as Mercury or asteroids, Anand said, adding that it only takes mild heat of around 100 degrees Celsius to liberate the water from the beads.

The amount of water hosted by impact glass beads in lunar soils may reach up to 2.7 × 10¹⁴ kg, the study estimates, "which could be a water reservoir for in situ utilization in future lunar exploration."

(With input from AFP)

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