Astronauts May One Day Drink Water From Ancient Moon Volcanoes
There are no active volcanoes on the Moon to be found today, but recent discoveries show that the Moon was far longer geologically active than previously believed.
From 4 to 2 billion years ago, a series of volcanic eruptions broke loose on the Moon, covering large parts of its surface in basalt lava. As the lava cooled down, it created the dark blotches, or Maria, that give the face of the Moon its familiar appearance today.
Now, new research from CU Boulder suggests that volcanoes may have left another lasting impact on the lunar surface: sheets of ice that dot the Moon’s poles and, in some places, could measure dozens or even hundreds of meters thick.
“We envision it as a frost on the Moon that built up over time,” said Andrew Wilcoski, lead author of the new study and a graduate student in the Department of Astrophysical and Planetary Sciences (APS) and the Laboratory for Atmospheric and Space Physics (LASP) at CU Boulder.
The researchers drew on computer models to try to recreate conditions on the Moon long before complex life arose on Earth. They discovered that ancient Moon volcanoes spewed out huge amounts of water vapor, which then settled onto the surface forming stores of ice that may still be hiding beneath more recent layers of dust and debris.
“It’s possible that 5 or 10 meters below the surface, you have big sheets of ice, a potential resource for future Moon explorers who will need water to drink and process into rocket fuel,” says study co-author Paul Hayne, an assistant professor in APS and LASP.
The new study adds to a growing body of evidence that suggests that the Moon may be awash in a lot more water than scientists once believed. In a 2020 study, Hayne and his colleagues estimated that large areas of the lunar surface could be capable of trapping and hanging onto ice, mostly near the Moon’s north and south poles. Where all that water came from in the first place is unclear.
“There are a lot of potential sources at the moment,” Hayne says. “Volcanoes could be a big one.” The planetary scientist explained that from 2 to 4 billion years ago, tens of thousands of volcanoes erupted across its surface, generating huge rivers and lakes of lava, not unlike the features you might see in Hawaii today, only much more immense. “They dwarf almost all of the eruptions on Earth.”
Recent research from scientists at the Lunar and Planetary Institute in Houston shows that these volcanoes likely also ejected towering clouds made up of mostly carbon monoxide and water vapor. These clouds then swirled around the moon, potentially creating a thin and short-lived atmosphere.
Based on this scenario, the new study simulated what happened to this atmosphere.
The team used estimates that, at its peak, the Moon experienced one eruption every 22,000 years, on average. The researchers then tracked how volcanic gases may have swirled around the Moon, escaping into space over time. And, they discovered, conditions may have gotten icy. According to the group’s estimates, roughly 41 percent of the water from volcanoes may have condensed onto the Moon as ice.
“The atmospheres escaped over about 1,000 years, so there was plenty of time for ice to form,” Wilcoski said.
The group calculated that about 5,000 cubic-kilometers of volcanic water could have condensed as ice during that period. That’s more water than currently sits in Lake Michigan. And the research hints that much of that lunar water may still be present today. Most of that ice has likely accumulated near the Moon’s poles and may be buried under several meters of lunar dust and debris deposited by meteorite impacts in the past 2 billion years.
The paper “Polar Ice Accumulation from Volcanically Induced Transient Atmospheres on the Moon” is published in the journal The Planetary Science Journal (2022). Materials provided by the University of Colorado at Boulder.