Volcanic Eruptions Gave the Ancient Moon a Temporary Atmosphere

Earth's moon art
An artist's impression of Earth's moon shows lavas erupting, venting gases and producing a visible atmosphere. (Image credit: NASA MSFC)

Earth's moon doesn't have much of an atmosphere today. However, it may have had a more prominent atmosphere 3 billion to 4 billion years ago, when volcanic eruptions spewed giant clouds of gas above the lunar surface, a new study has found. 

Today's moon is covered in dead volcanoes and dark maria, or plains that consist of hardened lava. The lunar atmosphere is so thin it's not even technically an atmosphere — instead, it's considered an "exosphere," with molecules that are gravitationally bound to the moon but are too sparse to behave like a gas. 

A new study from scientists at NASA's Marshall Space Flight Center in Huntsville, Alabama, and the Lunar and Planetary Institute (LPI) in Houston suggests that the moon's ancient volcanoes produced a temporary atmosphere that lingered for 70 million years before dissipating into space. [How the Moon Evolved: A Photo Timeline]

Samples of volcanic glasses collected by Apollo astronauts in the 1970s revealed that magma beneath the lunar surface billions of years ago "carried gas components, such as carbon monoxide, the ingredients for water, sulfur, and other volatile species," LPI officials said in a statement

In the new study, the researchers calculated how much gas rose from the lavas that flowed from the lunar volcanoes. They determined that enough gases accumulated around the moon to form an atmosphere, and that this atmosphere grew faster than it could escape into space. 

LPI officials said that the findings may have big implications for future exploration of the moon, because it "quantifies a source of volatiles that may have been trapped from the atmosphere into cold, permanently shadowed regions near the lunar poles and, thus, may provide a source of ice suitable for a sustained lunar exploration program." 

The study was published online Sept. 25 in the journal Earth and Planetary Science Letters

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Hanneke Weitering
Contributing expert

Hanneke Weitering is a multimedia journalist in the Pacific Northwest reporting on the future of aviation at FutureFlight.aero and Aviation International News and was previously the Editor for Spaceflight and Astronomy news here at Space.com. As an editor with over 10 years of experience in science journalism she has previously written for Scholastic Classroom Magazines, MedPage Today and The Joint Institute for Computational Sciences at Oak Ridge National Laboratory. After studying physics at the University of Tennessee in her hometown of Knoxville, she earned her graduate degree in Science, Health and Environmental Reporting (SHERP) from New York University. Hanneke joined the Space.com team in 2016 as a staff writer and producer, covering topics including spaceflight and astronomy. She currently lives in Seattle, home of the Space Needle, with her cat and two snakes. In her spare time, Hanneke enjoys exploring the Rocky Mountains, basking in nature and looking for dark skies to gaze at the cosmos.