The water locked in the soil on the moon has been found to consist of solar wind particles, more commonly known as charged particles released from the sun.
When NASA's Lunar crater Observation and Sensing satellite (LCROSS) crashed into the lunar crater in 2009, it proved that the long-held belief that the moon is dry is wrong. Materials ejected from the moon after the crash were found to be rich in water ice.
Now, researchers have found that the soil on the moon consists of water that is mainly made up of solar wind particles.
U-M's Youxue Zhang and colleagues from the University of Tennessee and the California Institute of Technology presented the findings that support solar-wind production of water ice on the moon. This study was published online Oct. 14 in the journal Nature Geoscience.
The first author of the paper is Yang Liu of U-T. She is a U-M alumna who earned her doctorate under Zhang, who is a professor in the Department of Earth and Environmental Sciences.
In the paper, the researchers present infrared spectroscopy and mass spectrometry analyses of Apollo samples that reveal the presence of significant amounts of hydroxyl inside glasses formed in the lunar regolith by micrometeorite impacts. Most of the infrared spectroscopy work was done at Zhang's U-M lab, and the mass spectroscopy was conducted at Caltech.
"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," said Zhang, the James R. O'Neil Collegiate Professor of Geological Sciences. "Lunar regolith is everywhere on the lunar surface, and glasses make up about half of lunar regolith. 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."
