14 DAY TRIAL // According to the conclusions of a new scientific study by researchers with the Department of Earth, Planetary and Space Sciences at the University of California in Los Angeles (UCLA), past researches may have overestimated that amount of water present on the Moon. These conclusions are based on a new analysis of the mineral apatite, which can be found in rock samples returned from the Moon.
The science group was led by Jeremy Boyce, who is an assistant researcher and adjunct assistant professor with the DEPSS. He and his colleagues were able to create a computer model capable of predicting exactly how the mineral would have crystallized from bodies of lunar magma, shortly after the natural satellite was produced following an impact between early Earth and a Mars-sized object.
Understanding the exact circumstances under which this crystallization process occurred is very important towards being able to accurately estimate the amount of water that may have been stored inside the Moon. One of the things that first drew researchers' attention to lunar apatite was the fact that it was unusually rich in hydrogen, Moon Daily reports.
This led many scientists to argue that these crystals could have only formed in a water-rich environment. The new investigation suggests that this may have not been the case. “The mineral apatite is the most widely used method for estimating the amount of water in lunar rocks, but it cannot be trusted,” says Boyce, who is based at the College of Letters and Science.
Details of the new study were published in a paper that appears in the March 20 online issue of the top journal Science. The work is scheduled to appear in print as well, in a future edition of the journal. “Our new results how that there is not as much water in lunar magma as apatite would have us believe,” Boyce says of the new study.
Until 2010, when the hydrogen-rich nature of apatite was discovered, most geologists believed that the Moon was almost entirely devoid of water. Subsequent analyses of the mineral hinted at an ore watery-rich past, but scientists failed to account for the deceptive nature of apatite, the UCLA team argues.
Boyce explains that apatite only incorporates hydrogen from water in its structure during the crystallization process if its preferred chemicals, fluorine and chlorine, are no longer available. “Early-forming apatite is so fluorine-rich that it vacuums all the fluorine out of the magma, followed by chlorine,” the investigator says.
“Apatite that forms later doesn't see any fluorine or chlorine and becomes hydrogen-rich because it has no choice,” he adds. Since this shift occurs only after a long period of time, the mineral's hydrogen content cannot be used as an accurate measuring stick for determining the original amount of water that existed on the Moon after it formed.
“We had 40 years of believing in a dry moon, and now we have some evidence that the old dry model of the moon wasn't perfect. However, we need to be cautious and look carefully at each piece of evidence before we decide that rocks on the moon are as wet as those on Earth,” Boyce concludes.