•Water on the Moon has two potential sources: water carried by comets and other bodies that impact the Moon, and in situ production. The latter is theorized to occur when hydrogen ions in the solar wind (protons) chemically combine with oxygen atoms in the Moon’s minerals (oxides, silicates, etc.) to form water or hydroxyl groups, the possible precursors to water. Water (H2O) and its chemical compound, the hydroxyl group (-OH), exist as hydrates and hydroxides of the Moon’s minerals. There is strong evidence that these compounds are present in low concentrations over much of the Moon’s surface. In fact, adsorbed water has been estimated to be present in concentrations of 10 parts per million to 1,000 parts per million. This mineral-bound water, or hydroxylated regolith, should not be confused with water ice.
Uncertain evidence of the presence of liquid water on the Moon has been found in various models that assume the presence of bound hydrogen. Moon scientists have been debating the possibility of water deposits for decades. Now, they are writing a report saying that they are “confident that the decades-long debate is over.” “There is water on the Moon, everywhere, not just in minerals, but in fragmented form on the surface and probably in the form of ice blocks or slabs deep down.” In 1961, Caltech researchers Kenneth Watson, Bruce C. Murray and Harrison Brown first suggested that there might be ice in the bottoms of polar lunar craters. In 1978, it was reported that the samples returned by the Soviet Luna 24 probe contained 0.1% water by mass. In 1998, the Lunar Prospector spacecraft measured the amount of hydrogen in the regolith near the polar regions. This instrument is a neutron spectrometer that can detect the amount and location of hydrogen within 50 parts per million. In 2009, the Moon Mineralogy Mapper (M³) instrument on the Chandrayaan-1 spacecraft detected absorption characteristics on the Moon’s surface at around 2.8-3.0 micrometers. On November 13, 2009, NASA announced that the spectral presence of water had been confirmed in the debris cloud created by the impact of the LCROSS spacecraft on the Cabeus crater. However, what was detected was the hydroxyl group (·OH), which is thought to be water. The principal mission scientist, Anthony Colaprete, stated that the impact appeared to contain ice in a crystalline structure that carried water. Subsequent analysis determined that the concentration of water was “5.6% ± 2.9% by mass.”
Inga kommentarer ännu