image: Water and their precursors were stored in lunar silicates and released into the gas phase by (micro)meteorite impact. view more
Credit: Molecules and data courtesy of Cheng Zhu and Ralf I. Kaiser; background image courtesy of NASA/Goddard/Conceptual Image Lab.
Researchers report a plausible mechanism for water formation on the moon. Recent observations support the existence of water ice on the moon, but the origin of this water remains uncertain. Ralf Kaiser and colleagues irradiated samples of a substitute of lunar material, anhydrous olivine, with deuterium ions, a proxy for solar wind, under ultra-high vacuum conditions and at the extreme low temperatures of regions on the moon. No water was detected following irradiation, even after increasing the temperature to lunar mid-latitude daytime temperatures. However, molecular deuterium was detected following warming, suggesting that ions from the solar wind can be implanted and stored in the lunar rock. In a second set of experiments, irradiation of the olivine by deuterium ions was followed by laser-heating to simulate the thermal effects of micrometeorite impacts. A burst of ions with charge-to-mass ratios matching that of ionized D2O was observed in the gas phase during the laser pulse. Water continued to be produced during laser pulses after the temperature was increased, suggesting that the olivine was storing D2O precursors that were released by laser-heating. The results suggest that micrometeorite-induced thermal shocks to solar wind-exposed silicates could potentially generate and liberate water on the moon and other airless bodies in the Solar System, according to the authors.
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Article #18-19600: "Untangling the formation and liberation of water in the lunar regolith," by Cheng Zhu et al.
MEDIA CONTACT: Ralf I. Kaiser, University of Hawaii at Manoa, Honolulu, HI; tel: 808-956-5731, 808-255-5727; e-mail: ralfk@hawaii.edu; Jeffrey Gillis-Davis, University of Hawaii at Manoa, Honolulu, HI; tel: 808-956-5738, 808-294-2055; e-mail: gillis@higp.hawaii.edu
Journal
Proceedings of the National Academy of Sciences