Scientists Just Reported The First Unambiguous Detection Of Water On Moon

It’s official. There is water on the Moon.

We ᴀssumed there was for almost a decade, based ondetections announced in 2009, but the wavelengths used left space forinterpretation. Scientists announce the first unambiguous discovery using adistinct wavelength peculiar to water. Those 2009 conclusions appeared to be correct.

Because the 2009 detections were produced in the3-micrometer infrared region, the uncertainty emerged. Water or anotherhydroxyl molecule containing hydrogen and oxygen were the only options at thiswavelength.

A team of scientists led by NASA Goddard Space FlightCentre astronomer Casey Honniball sought to investigate the wavelength that mayvalidate or refute such conclusions. The 6-micrometer infrared band shoulddisplay a line that can only be formed by two hydrogen atoms and one oxygenatom – the H-O-H bend vibration.

However, establishing an unambiguous detection in thatspectrum is difficult. It necessitates the use of the Stratospheric Observatoryfor Infrared Astronomy (SOFIA), a one-of-a-kind telescope flying on an aircraftabove the most of the Earth’s atmosphere.

“SOFIA is the only current and plannedobservatory capable of these observations,” Honniball told ScienceAlert.

“Current lunar spacecraft do not have instrumentsthat can measure at 6 micrometres, and from the ground, Earth’s atmosphereblocks 6-micron light, and so it cannot be done from ground-basedobservatories. SOFIA flies above 99.9 percent of the Earth’s water vapour,which allows 6-micrometre light to pᴀss through and be observed. And luckilySOFIA’s FORCAST instrument can make 6-micrometre measurements and look at theMoon.”

The researchers used FORCAST to thoroughly study theregion where the 3-micrometer detections were made – high southernlaтιтudes near the south pole. They discovered the emission line they had beenlooking for – the one-of-a-kind signature that could only be produced by theH-O-H bend vibration.

Based on these findings, the team predicts waterabundances of 100 to 400 parts per million, which is compatible with MoonMineralogy Mapper 3-micrometre detections.

There are no liquid lakes splashing around on thelunar surface, and any frozen water would sublimate as soon as it was exposedto sunlight. However, there are several possibilities for the Moon stillharboring surface water.

“We mainly think the water is in glᴀss,”Honniball said. “When a micrometeorite impacts the Moon, it meltssome lunar material, which quickly cools and forms a glᴀss. If there is wateralready present, formed during or delivered during the impact, some of thewater can be captured in the structure of the glᴀss while it cooled.”

Another possibility – patches of persistent darknessin polar craters – was investigated in a separate article headed by astronomerPaul Hayne of the University of Colorado Boulder. High crater rims at highlaтιтudes produce places where sunlight never reaches.

Temperatures in these areas seldom rise above -163degrees Celsius (-260 degrees Fahrenheit), producing cold traps that mightharbor concealed patches of aqueous ice. Using data from NASA’s Lunar Reconnaissance Orbiter,Hayne and his colleagues determined that the permanently shadowed surface mightcover up to 40,000 square kilometers (15,000 square miles). And 60% ofthat is at the South Pole.

“The temperatures are so low in cold traps thatice would behave like a rock,” Hayne said. “A billion years if watergets in there.”

Both papers have far-reaching consequences for futurelunar expeditions. As part of the Artemis mission, NASA plans to create a lunarbase; if an adequate source of water can be located nearby, lunar occupantsmight utilize it for drinking, producing crops, and even splitting itusing electrolysis to produce hydrogen for rocket fuel.