Some beads were made millions of years ago when asteroids impacted the Moon, while others were formed by ancient volcanoes. Scientists think the water was formed by a chemical reaction between hydrogen ions generated by the sun and oxygen atoms within the beads, which were brought to the lunar surface by solar winds. The water-filled beads are very small, measuring “tens of micrometres to a few millimetres.” Yet, there are enough on the Moon’s surface to furnish (theoretically) an estimated 270 trillion kilos of water – enough to fill 100 million Olympic-sized swimming pools.
