Apollo Rocks Show Traces of Water: Study May Shed Light on Moon Formation and Evolution
Cowen, Ron, Science News
A new analysis of moon rocks has revealed that the moon isn't as bone dry as researchers had thought, whetting the appetite of scientists who seek a deeper understanding of how Earth's natural satellite arose and evolved.
Because the moon is believed to have coalesced from the debris created when a Mars-sized body struck Earth some 4.5 billion years ago, the finding also suggests that Earth acquired a substantial supply of water earlier in its history than some scientists had suspected.
When the moon rocks were brought back to Earth by the Apollo astronauts, the tiny, volcanically formed glass beads inside showed no signs of water. But Alberto Saal of Brown University in Providence, R.I., and colleagues have reexamined the rocks with a more sensitive instrument, using a narrow beam of cesium ions.
The new measurements reveal that the concentration of water in the rocks is less than 50 parts per million, says co-investigator Erik Hauri of the Carnegie Institution for Science in Washington, D.C. A critical finding he notes, is that the concentration of water decreases dramatically from the center to the rim of the beads, suggesting that 95 percent of the water once held by the moon was lost when volcanic eruptions belched water vapor and other volatile gases. …