NASA Uncovers Lunar Clues to Earth's Water Origins

New study challenges assumptions about meteorite contributions to our planet's oceans

Apr. 10, 2026 at 8:41pm

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A bold, abstract painting in earthy tones of green, blue, and brown, featuring sweeping geometric arcs, concentric planetary circles, and precise botanical spirals, conceptually representing the complex scientific forces and concepts behind the origins of Earth's water.A groundbreaking NASA study unravels the ancient history of the Moon and its role in shaping Earth's water supply.Houston Today

A NASA-led study has revealed groundbreaking insights into the ancient history of the Moon and its role in shaping Earth's water supply. By analyzing lunar regolith samples from the Apollo missions, researchers have discovered that meteorites arriving on Earth since approximately four billion years ago could not have been the primary source of our planet's water, challenging previous assumptions.

Why it matters

This finding raises intriguing questions about the origins of Earth's water and the importance of lunar regolith in preserving cosmic history. The study highlights the Moon's value as a unique archive, allowing scientists to decipher the impact history of Earth's neighborhood over billions of years.

The details

The study, published in the Proceedings of the National Academy of Sciences, reveals that even under the most optimistic assumptions, meteorites arriving on Earth since approximately four billion years ago could not have been the primary source of our planet's water. The researchers turned to triple oxygen isotopes in lunar regolith, offering a precise 'fingerprint' of the meteorite composition unaffected by external forces. The oxygen-isotope measurements showed that approximately 1% by mass of the regolith contained material from carbon-rich meteorites, which were partially vaporized upon impact with the Moon.

  • The study was published in April 2026.

The players

Tony Gargano

A postdoctoral fellow at NASA's Johnson Space Center and the Lunar and Planetary Institute.

Justin Simon

A planetary scientist at NASA Johnson's Astromaterials Research and Exploration Science Division.

Karen Fox

The lead author of the study.

Molly Wasser

The co-author of the study.

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What they’re saying

“The lunar regolith is a unique archive, allowing us to decipher the impact history of Earth's neighborhood over billions of years. The oxygen-isotope fingerprint helps us extract the impactor signal from a complex mixture of melted, vaporized, and reworked materials.”

— Tony Gargano, Postdoctoral fellow at NASA's Johnson Space Center and the Lunar and Planetary Institute

“Our research doesn't deny the presence of water in meteorites. Instead, it highlights the difficulty of late meteorite delivery being the dominant source of Earth's oceans, based on the Moon's long-term record.”

— Justin Simon, Planetary scientist at NASA Johnson's Astromaterials Research and Exploration Science Division

What’s next

The Artemis missions will unlock a new era of discoveries, offering a more comprehensive understanding of the Moon and its role in Earth's water history. The lunar samples collected during these future missions will provide additional insights into the origins of our planet's water supply.

The takeaway

This study challenges the long-held assumption that late meteorite delivery was the primary source of Earth's water, suggesting that other factors may have played a more significant role. The findings highlight the importance of lunar regolith as a time capsule, allowing scientists to decipher the impact history of our planet's neighborhood over billions of years.