NASA's LRO Spies Water Molecules Moving Around Dayside Of The Moon

NASA has leveraged an instrument that is aboard the Lunar Reconnaissance Orbiter called the Lyman Alpha Mapping Project or LAMP. That instrument can measure the layer of molecules that are temporality stuck to the surface of the moon, allowing it to report on changes in lunar hydration throughout a day.

The moon, was in the past, considered to be arid with any water that existed on the moon being stuck as pockets of ice in craters that are permanently shaded at the moon's poles. What we know now is that surface water is found in pockets of molecules that are bound to the lunar soil.

The amount of water and location of the water changes as the day goes on. Water is more common at higher latitudes according to NASA, but the molecules move around the surface of the moon as it heats. Water molecules stay bound to the lunar soil until surface temperatures peak near lunar noon.

When that temperature peak hits, the molecules thermally desorb and can bounce to any nearby location cold enough for the molecule to stick or populate the moon's atmosphere. LAMP's light collection mode was converted recently to allow the instrument to measure reflected signals on the lunar dayside more precisely allowing improved tracking of where water is and how much is present.

As for where water molecules on the lunar surface come from, scientists hypothesize that the source is hydrogen ions in the solar wind. However, if that was true when the moon is behind the Earth and shielded from the solar wind, NASA says the "water spigot" should turn off, but it doesn't. LAMP observations suggest that water builds up over time rather than "raining" onto the lunar surface from the solar wind. Scientists say that the latest data from LAMP is important in advancing our understanding of the lunar water cycle.