The inside of the moon might not be all wet after all. A new study suggests that, contrary to recent work, the lunar interior is as bone-dry as scientists thought 40 years ago, when NASA astronauts lugged home the first moon rocks.
New analyses of chlorine in those rocks, published online August 5 in Science, indicate that the moon contains just one-10,000th to one-100,000th the water that the Earth’s interior does.
Studying the wateriness of different worlds can illuminate how they evolved, says geochemist Zachary Sharp of the University of New Mexico in Albuquerque, lead author of the new paper. “It’s a window into processes that shaped the solar system soon after it formed.”