Water on the moon

Water trapped in tiny, shiny multicoloured glass beads has been found in the lunar dirt brought back to earth by Chang'e 5, China's fifth lunar exploration mission, in early December 2020. It was also that country's first lunar-sample return mission. However, scientists analysed the lunarsoil the Chinese space mission scooped from the moon's surface and came up with the findings. A scientist from China's Nanjing University, China, Heju Hui, who took part in the analysis, said the glass beads were the size of one to several hairs. Here a single strand of hair measures 0.12 millimetres in width. So, the amount of water in these minuscule glass globules is also very small. But consider that there are billions of such glass beads on the moon's surface. If it is possible to extract the water the glass beads contain and if the water proves to be drinkable, one day moon explorers might be able to get substantial amount of water from the moon.

However, mining this water from those glass beads will not be easy. Maybe, high-tech robots will be used someday to do the job. But where do these water-containing glass beads come from in the first place? Glass may be created by the impact of asteroids on the moon's surface. Cooled molten lava from lunar volcanic eruptions may be another source. Lunar soil brought to Earth by Apollo lunar missions half a century ago also contained such glass beads. But how could water enter those glass pellets? Solar wind that constantly bombards the moon's surface contains protons, which make hydrogen's nucleus. And this hydrogen ion interacts with mineral oxide present in the moon's soil. The oxygen thus released from the mineral oxide bonds with the solar wind's hydrogen ion, that is proton, to produce water. And that water gets trapped in the glass beads.This discovery is of great significance, for it promises to provide scientists with a clue about the origin of water both on the moon and the earth.

However, it is not from the water-filled glass beads that scientists for the first time came to know that there is water on the moon. By studying the samples of moon's soil brought to earth by the US, Russian and, lastly, the Chinese exploratory missions to the moon, scientists have found signs of water on the surface of the earth's natural satellite. Add to it the photographs taken by probes sent from time to time to circle the moon. All these crewed and uncrewed space missions to the moon collected data on different aspects of this celestial body including the possibility of its holding water.

And scientists finally confirmed that the moon is not purely a waterless dust ball as it was believed until recently. Space missions flying past the moon's permanently shadowed polar craters where sunlight never reaches have detected large quantities of water in the form of ice. In 2009, for instance, NASA, the US space agency that conducts civil space programmes, launched the robotic Lunar Reconnoissance Orbiter (LRO) along with Lunar Crater Observation and Sensing Satellite (LCROSS). LCROSS was made to crash along with the upper stage of the rocket that carried LRO into a dark crater on the moon's south pole. LCROSS, which flew into the cloud of debris created by the impact, detected the existence of 155 kilogrammes of water. Proof of the existence of water on any celestial body including the moon is of great interest to scientists. Because water is another name for life.

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