Between 2 and 4 billion years ago, the moon was a volcanic hotspot. Tens of thousands of volcanoes were erupting on the surface, releasing hundreds of thousands of square kilometers of lava onto the lunar surface.
This activity created massive lava rivers and lakes similar to features of today’s Hawaii, but on a much larger scale.
“They dwarf almost all eruptions on Earth,” said Paul Hayne, assistant professor in the Department of Astrophysical and Planetary Sciences and the Laboratory of Atmospheric and Space Physics at the University of Colorado at Boulder, in a statement.
When these lunar volcanoes erupted, it is also likely that they released giant clouds consisting of carbon monoxide and water vapor. These clouds were moving and could have created thin, temporary atmospheres.
But it’s also possible that water vapor deposited on the lunar surface and formed layers of ice that might have existed in craters at the lunar poles today. These ice caps could be between tens and hundreds of feet thick.
“We think of it as frost on the moon that has built up over time,” said lead author Andrew Wilcoski, a doctoral student in the Department of Astrophysical and Planetary Sciences and the Atmospheric and Space Physics Laboratory at CU Boulder. , in a press release.
If humans had been alive on Earth when this happened, a shadow of frost might have been visible at the border of night and day on the lunar surface, the researchers said.
As NASA’s Artemis mission prepares to return humans to the moon and land at the lunar south pole for the first time later this decade, this ice could provide drinking water and serve as a fuel resource for rocket, Hayne said.
“It’s possible that 5 or 10 meters (16 to 33 feet) below the surface you have large patches of ice,” he said.
Scientists tried to figure out where the water came from, which led researchers to the volcano theory. They imagined the clouds of water vapor forming like frost on the lunar surface, the same way they form on Earth after a cold night.
Wilcoski and Hayne teamed up with Margaret Landis, a research associate at CU Boulder’s Atmospheric and Space Physics Laboratory, to model what the moon looked like a few billion years ago.
At the time, the moon experienced a volcanic eruption roughly every 22,000 years. The team calculated that 41% of the water vapor released during eruptions could then form ice on the lunar surface.
That’s about 18 quadrillion pounds (8.2 quadrillion kilograms) of volcanic water — more water than Lake Michigan’s current level — turning into lunar ice, according to the study. The thick polar caps may have once been visible from Earth.
“The atmospheres escaped over about 1,000 years, so there was plenty of time for the ice to form,” Wilcoski said.
Although most of this ice may still exist on the moon today, it is likely buried under several feet of lunar regolith or dust.
“We really have to dig and look for it,” Wilcoski said.