It has long been argued that there may be water and other volatile species on the moon’s surface. The past two decades of lunar exploration have discovered significant amounts of water on the lunar surface.

It has been suggested that a hydrated layer exists at depth in the lunar soil, buffering a global water cycle on the moon. However, a reservoir has yet to be identified for this hydrated layer.

Scientists at the Institute of Geology and Geophysics (IGG) of the Chinese Academy of Sciences (CAS) have reported the abundance, hydrogen isotope composition, and core-to-edge variations of water measured in impact glass beads extracted from lunar soils returned by the Chang’e-5 mission. They found that impact glass beads in Chang’e-5 (CE5) lunar soils contain some water.

According to thorough research, these glass beads are likely a brand new reservoir of water on the moon that records the dynamic entry and exit of water from the solar wind and serves as a protective barrier to the moon’s surface water cycle.

Previous research on the water content of the small mineral grains of the lunar soil, impact-produced agglutinates, volcanic rock, and pyroclastic glass beads has failed to explain how water is retained, released, and replenished on the surface of the moon (i.e., lunar). surface water cycle). So there must be a water reserve in the moon’s soil that can withstand the water cycle of the lunar surface.

Impact glass beads, a common component of lunar soils with an amorphous character, were proposed by PhD student HE Huicun under the supervision of Prof. HU Sen as a candidate for research on the unexplained hydrated layer or reservoir in lunar soils.

She thoroughly analyzed the petrography, key element composition, water content, and hydrogen isotope composition of the impact glass beads returned by the CE5 mission to locate and describe the missing water reservoir on the lunar surface.

The exposed surfaces of the CE5 impact glass beads are smooth and have uniform chemical compositions. Extreme deuterium depletion features and water abundance up to 2,000 gg-1 define them. The fact that the water in the CE5 impact glass beads comes from solar wind is reflected in the negative association between water abundance and hydrogen isotope composition.

The water abundance along six transects in five glass beads was also examined by the scientists, revealing the hydration profiles of water coming from the solar wind. Subsequent degassing overlapped some of the glass beads. The impact glass beads spongily absorbed the moon’s surface water cycle. The amount of water hitting glass beads believed to be added to lunar soils ranges from 3.0 1011 kg to 2.7 1014 kg, according to the study.

prof. HU Sen said: “These findings indicate that the impact glasses on the surface of the moon and other airless bodies in the solar system are capable of storing and releasing solar wind-derived water into space.”

Magazine reference:

  1. He, H., Ji, J., Zhang, Y. et al. A solar wind-derived lunar water reservoir hosted by impact glass beads. Wet. geosci. (2023). DOi: 10.1038/s41561-023-01159-6