October 15, 2012
Solar Winds Could Play Role In Formation Of Lunar Water
redOrbit Staff & Wire Reports - Your Universe Online
The researchers studied soil samples brought back from the lunar surface during the Apollo missions, and discovered that they contained compounds known as hydroxyls, which are essentially substructures of an H2O molecule, according to Telegraph Science Correspondent Nick Collins.
Yang Liu from the University of Tennessee and colleagues believe that the molecules were probably formed on the Moon's surface by the solar wind -- a stream of charged particles that originates from the sun. Their theory is that a reaction between hydrogen ions in the solar wind and loose surface soil on the moon known as regolith was responsible for the formation of the hydroxyls, the AFP added.
The team used infrared spectroscopy and mass spectrometry to study samples brought back from the Apollo 11, 16 and 17 missions to discover what they called "significant" amounts of hydroxyl formed within the regolith. They then combined that data with Fourier transform infrared spectroscopy and secondary ion mass spectrometry techniques to unearth which chemical form of the hydrogen the soil contained, as well as its isotopic composition.
"We found that the 'water' component, the hydroxyl, in the lunar regolith is mostly from solar wind implantation of protons, which locally combined with oxygen to form hydroxyls that moved into the interior of glasses by impact melting," University of Michigan Geological Sciences Professor Youxue Zhang, who was involved in the study, said in a statement Sunday.
"Lunar regolith is everywhere on the lunar surface, and glasses make up about half of lunar regolith," Zhang added. "So our work shows that the 'water' component, the hydroxyl, is widespread in lunar materials, although not in the form of ice or liquid water that can easily be used in a future manned lunar base."
According to the Ann Arbor-based university, the discovery suggests that the moon's cold traps, which as essentially polar craters that exist in perpetual shadow, could contain hydrogen atoms originating from the solar wind. If that is true, Liu said that it could also mean that Mercury and some asteroids could also harbor water in some form.
"Until now, the source of water in the inner Solar System, the region extending to the asteroid belt between Mars and Jupiter, is believed to be comets and other water-rich rocks which whack into planets and other bodies," the AFP reported. "So if the study is right, hydrogen from the solar wind could be a second, hitherto unimagined source."