What’s the source of the ice at the moon’s south pole?
Paul Scott Anderson in SPACE | October 19, 2019

A new study from Brown University suggests that different deposits of ice at the moon’s south pole not only originated from different sources, but also vary greatly in age.


Deep and shadowed Shackleton Crater near the moon’s south pole is one location where scientists have found deposits of water ice. The ice has the potential to reveal insights about the moon’s history, and the history of our solar system. And it’s potentially useful to future moon explorers. Image via NASA/Goddard Space Flight Center/Leonard David’s Inside Outer Space.
We tend to think of the moon as a dusty, bone-dry place, and for the most part, that is true. But the moon does have ice, in particular at its south pole, hidden in shadowed craters. Just how the ice got there has been a bit of a mystery, but now a new study suggests it may have various sources, both ancient and more recent.

The new peer-reviewed findings were published in Icarus on September 30, 2019.

This water ice has much value, both to scientists and future human explorers. According to Ariel Deutsch, lead author of the study and a graduate student at Brown University:

The ages of these deposits can potentially tell us something about the origin of the ice, which helps us understand the sources and distribution of water in the inner solar system. For exploration purposes, we need to understand the lateral and vertical distributions of these deposits to figure out how best to access them. These distributions evolve with time, so having an idea of the age is important.

The findings suggest that not only is some of the ice much older than the rest, but that there are probably different sources as well. Older ice could have come from water-bearing comets and asteroids or ancient volcanism. More recent ice deposits might be the result of pea-sized micrometeorites or implantation by solar wind.