A new, high-resolution topographic map of the lunar surface indicates that the outer layers of the moon are likely bone dry. The new data, obtained from a laser-mapping instrument onboard the Japanese SELENE satellite, also known as Kaguya, shows that the moon's surface is rigid, not buoyant and flexible as would be expected if a significant amount of water flowed underneath it.
"The surface can tell us a lot about what's happening inside the moon, but until now mapping has been very limited," study co-author C. K. Shum, a professor of earth sciences at Ohio State University, said in a statement. "For instance, with this new high-resolution map, we can confirm that there is very little water on the Moon today, even deep in the interior. And we can use that information to think about water on other planets, including Mars."
Mars, Shum and his colleagues write, may have more interior water than the moon, as it is already known to have water ice on the surface and boasts an increasingly interesting hydrological history. But based on its surface composition and present lack of plate tectonics, the outer layers of the Red Planet are likely fairly parched as well.
The findings, along with a suite of other studies from Kaguya, were presented in this week's Science.