A meteorite from Alaska challenges the theory of how Earth acquired its water

Researchers find Earth may have had its own hydrogen source to form water.

: Researchers have discovered significant quantities of hydrogen in the LAR 12252 meteorite, challenging the theory that asteroids delivered Earth's water. The enstatite chondrite meteorites, like LAR 12252, share compositional similarities with early Earth, suggesting Earth could generate water independently. The X-ray examinations revealed substantial hydrogen sulfide in the matrix, implying intrinsic hydrogen content. This discovery, led by scientists James Bryson and Tom Barrett at the University of Oxford, suggests water formation may be a natural planetary process.

The longstanding hypothesis that asteroids brought water to Earth has been critically evaluated with new evidence from the LAR 12252 meteorite. This meteorite, an enstatite chondrite found in Alaska, has provided groundbreaking insights into Earth's ancient hydrogen sources, indicating that water generation on the planet was likely independent of asteroid impacts. Enstatite chondrites are known for their compositional similarity to Earth 4.55 billion years ago, making them valuable proxies for understanding early planetary conditions.

James Bryson from the University of Oxford's Department of Earth Sciences, a co-author of the study, emphasized the importance of these findings, stating, “This finding supports the idea that the formation of water on Earth was a natural process, rather than a fluke of hydrated asteroids bombarding our planet after it formed.” The research used sophisticated X-ray technology to investigate the meteorite's matrix for sulfur compounds, leading to the discovery of hydrogen sulfide, a marker for intrinsic hydrogen.

The methodical examination of LAR 12252 revealed that the hydrogen in the matrix far exceeded that found in any previous study of the meteorite's terrestrial contamination-prone areas. Tom Barrett, the lead author and researcher at Oxford, noted, “We were incredibly excited when the analysis told us the sample contained hydrogen sulfide—just not where we expected.” This observation corroborates the notion that Earth was naturally pre-equipped with the hydrogen necessary for its abundant water.

These findings not only reassess the source of Earth's water but also add a new layer of understanding to planetary formation processes in our solar system. They suggest that other celestial bodies might also have acquired water independently of external sources, reshaping our perspective on water's prevalence in the universe.

Insights from the LAR 12252 meteorite offer crucial evidence supporting the theory that Earth’s wetness is inherent to its own geological composition. Such revelations continue to shape our understanding of how life-sustaining resources are distributed across the cosmos.

Sources: Margherita Bassi, NASA, University of Oxford

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