A recent NASA study sheds light on the Moon’s history of meteorite impacts and how they relate to water on Earth. This research helps clarify how much water meteorites could have provided to our planet over time.
Scientists believe meteorites played a key role in delivering water to Earth during the early solar system. A team led by Tony Gargano from NASA’s Johnson Space Center examined lunar soil, or regolith, using new techniques. Their findings suggest that, even with the best-case scenarios, meteorite impacts over the last four billion years contributed only a small fraction of Earth’s water.
Unlike Earth, where weather and geological processes erase impact records, the Moon’s surface retains these ancient marks. However, studying regolith isn’t straightforward. Traditional methods often focus on metal elements that can be altered by impacts, complicating researchers’ efforts to understand what the original meteorites contained.
To overcome this challenge, the team turned to triple oxygen isotopes. These isotopes serve as reliable “fingerprints” of meteorite composition. They discovered that around 1% of the regolith originated from carbon-rich meteorites that partially vaporized upon impact. By understanding these meteorites’ properties, they estimated how much water might have been delivered.
“The lunar regolith offers a time-capsule view of impacts in Earth’s vicinity,” Gargano explained. “The oxygen-isotope fingerprints help us untangle the complicated history of what has hit the Moon.”
The study’s insights also influence our understanding of water sources on both Earth and the Moon. When adjusted for Earth’s higher impact rates, the results indicate that meteorite contributions were likely minimal compared to the vast amounts of water in our oceans. Co-author Justin Simon stated, “This research doesn’t rule out meteorites delivering water, but it challenges the idea that they were the main source.”
On the Moon, while the amount of water from meteorites since 4 billion years ago is small concerning Earth’s oceans, it’s still significant for lunar exploration. Most of the Moon’s accessible water is found in permanently shadowed areas at the poles, offering potential resources for future missions, such as NASA’s Artemis program.
This ongoing exploration could lead to exciting discoveries. The samples the team analyzed came from areas near the Moon’s equator, where Apollo missions gathered rocks and dust more than 50 years ago. These samples have provided crucial insights, yet they only represent a tiny fraction of the Moon’s surface. Future missions under the Artemis program promise to bring back more samples, opening doors for new scientific breakthroughs.
“As a part of the next generation of Apollo scientists, I’m excited about what we can learn from Artemis,” Gargano said. “The Moon offers us tangible material to study, grounding our understanding of the solar system.”
For more details on NASA’s research, check out their [Astromaterials Research and Exploration Science Division](https://science.nasa.gov/astromaterials).
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Astromaterials, Earth's Moon, Johnson Space Center
