New research shows that if even a moderate amount of water delivered by asteroids to the Moon were buried in thickness, the lunar poles would contain gigaton deposits (1 billion metric tons) of ice in sheltered craters and beneath the surface.
By simulating over 4 billion years of history of impacts on the moon, the researchers were able to trace the origin and possible amount of ice that may be hidden from view under the lunar surface.
“We have studied the entire history of ice deposition on the Moon,” said Kevin Cannon, a planetary scientist based in Golden and lead author of a new study published in AGU Geophysical Research Letters.
Cannon and his team used conservative estimates of the amount of water that asteroids could contain when hitting the moon, and how much of it is likely to remain after the dust settles. Their results indicate that the Moon may contain much more water below the surface than previously thought.
“If the oldest regions were stable and accumulated ice for billions of years, then some of them could have very significant deposits, but the water in them could be buried at depths of 10 meters or more,” Cannon said.
Despite this depth, reserves of polar ice are likely to be available to astronauts on future lunar missions. Ice in sufficiently significant amounts can potentially be used as drinking water, oxygen and rocket fuel.
Scientists first hypothesized the existence of water on the moon many years before Neil Armstrong and Edwin “Buzz” Aldrin set foot on its surface. The moon is riddled with craters, some of which are deep enough to cast permanent shadows on their crests, under which ice, sheltered from the constant onslaught of the solar wind, has accumulated for potentially billions of years.
However, despite evidence of its existence, scientists have only recently confirmed that our closest neighbor contains water in abundance. Recent research has provided the first conclusive evidence of ice in sunlit parts of the Moon, where it is likely trapped in ice created by strong impacts, or in small quantities between grains of moon dust.
However, most of the ice on the Moon is trapped at the poles, where light is scarce and temperatures remain below -163 ° C.
Scientists have conducted a number of direct observations of ice at the poles of the Moon, but due to their extreme antiquity – most of the ice on the surface was formed more than 3 billion years ago during the nascent stages of the Moon’s development – most of the ice was covered with debris from asteroid impacts or was buried on depths inaccessible for detection by satellite ultraviolet and radar devices.
Consequently, estimating the amount of ice on the moon has been challenging. Most of the research done over the past few decades concludes that the deposits on the moon have only a shallow layer of snow or ice about a meter thick.
However, based on recent estimates, it is believed that even medium-sized craters at the poles can contain huge amounts of ice.