NASA reveals direct evidence of water on the moon...

[TheGreenGoblin]

Scientists have gathered some of the most compelling evidence yet for the existence of water on the moon – and it may be relatively accessible. The discovery has implications for future missions to the moon and deeper space exploration.

With no significant atmosphere insulating it from the sun’s rays, it had been assumed that the moon’s surface was dry – until the 1990s, when orbiting spacecraft found indications of ice in large and inaccessible craters near the moon’s poles.

Then in 2009, imaging spectrometers onboard India’s Chandrayaan-1 spacecraft recorded signatures consistent with water in light reflecting off the moon’s surface. Even so, technical limitations meant it was impossible to know if this really was H2O (water) or hydroxyl molecules (consisting of one oxygen atom and one hydrogen atom) in minerals.

Now, Casey Honniball at Nasa’s ASA Goddard Space Flight Center in Maryland, US, and colleagues have detected a chemical signature that is unambiguously H2O, by measuring the wavelengths of sunlight reflecting off the moon’s surface. The data was gathered by the Stratospheric Observatory for Infrared Astronomy (Sofia), a modified Boeing 747 carrying a 2.7-metre reflecting telescope.

The water was discovered at high latitudes towards the moon’s south pole in abundances of about 100 to 400 parts per million H2O. “That is quite a lot,” said Mahesh Anand, professor of planetary science and exploration at the Open University in Milton Keynes. “It is about as much as is dissolved in the lava flowing out of the Earth’s mid-ocean ridges, which could be harvested to make liquid water under the right temperature and pressure conditions.”

https://www.theguardian.com/science/202 ... ts-confirm

[Karearea]

^ interesting video.
Have heard SOFIA fly over a couple of times en route to the Southern Ocean, remarkable sound.

[G-CPTN]

If there is no atmosphere to retain water vapour, surely it is only a matter of time before all water evaporates?

[TheGreenGoblin]

If there is no atmosphere to retain water vapour, surely it is only a matter of time before all water evaporates?

Moon water ice will sublimate in sunlight, i.e. go from ice to water vapour that is then decomposed into hydrogen and oxygen molecules that are lost into space lost but in the darker extremely cold areas areas of craters and areas near the poles this process hasn't occurred it seems. The fact that this recent water was discovered in areas that are in sunlight implies that the water must be held in suspension in the soil I guess.

https://phys.org/news/2020-10-sofia-sun ... -moon.html

"Without a thick atmosphere, water on the sunlit lunar surface should just be lost to space," said Honniball, who is now a postdoctoral fellow at NASA's Goddard Space Flight Center in Greenbelt, Maryland. "Yet somehow we're seeing it. Something is generating the water, and something must be trapping it there."

Several forces could be at play in the delivery or creation of this water. Micrometeorites raining down on the lunar surface, carrying small amounts of water, could deposit the water on the lunar surface upon impact. Another possibility is there could be a two-step process whereby the Sun's solar wind delivers hydrogen to the lunar surface and causes a chemical reaction with oxygen-bearing minerals in the soil to create hydroxyl. Meanwhile, radiation from the bombardment of micrometeorites could be transforming that hydroxyl into water.

How the water then gets stored—making it possible to accumulate—also raises some intriguing questions. The water could be trapped into tiny beadlike structures in the soil that form out of the high heat created by micrometeorite impacts. Another possibility is that the water could be hidden between grains of lunar soil and sheltered from the sunlight—potentially making it a bit more accessible than water trapped in beadlike structures.