The Earth’s core may contain a surprisingly vast reservoir of hydrogen – potentially up to nine times more than all of the planet’s oceans combined. This discovery, published February 10, 2026, in Nature Communications, is reshaping our understanding of the planet’s internal structure and the origins of Earth’s water.
Researchers estimate the hydrogen could represent between 0.36% and 0.7% of the core’s total weight. This finding positions the Earth’s core as the largest known storage of hydrogen on the planet, dwarfing the amount found in surface water, which covers approximately 70% of the Earth’s surface. The implications of this discovery extend to our understanding of planetary formation and the evolution of life.
The research team, led by Dongyang Huang, assistant professor at the School of Earth and Space Sciences at Peking University, arrived at these conclusions by simulating the extreme temperatures and pressures found within the Earth’s core. They used iron as a proxy for the core’s metallic composition and observed how hydrogen interacted with silicon and oxygen at those conditions.
“The technique is fundamentally different from previous methods,” Huang explained. Researchers refined samples into needle-like shapes approximately 20 nanometers in diameter, then subjected them to a precisely controlled high voltage. Atoms within the samples were then ionized and counted individually.
The study suggests that Earth likely acquired most of its water – and therefore its hydrogen – during its formation, rather than through later impacts from comets, a theory previously proposed by some scientists. “The Earth’s core would have stored most of the water in the first million years of Earth’s history,” Huang stated. The mantle and crust hold the next largest amounts, with the surface containing the least.
The presence of hydrogen within the core is thought to have played a role in the generation of Earth’s magnetic field, which is essential for protecting the planet from harmful solar radiation. The interaction between silicon, oxygen, and hydrogen observed in the experiments provides clues about how heat was released from the core to the mantle, initiating this process.
Scientists have long theorized about the amount of hydrogen hidden within the Earth’s core, but quantifying it proved challenging due to the extreme conditions and the element’s small size. Previous research relied on X-ray diffraction to analyze iron crystals, but results varied widely. This latest method offers a more direct measurement.
Rajdeep Dasgupta, professor of Earth and Planetary Science at Rice University in Texas, who was not involved in the study, emphasized the importance of hydrogen’s presence during the Earth’s early development. “Hydrogen could only enter the metallic liquid that forms the core if it was available during the main phases of Earth’s growth and participated in core formation,” he said.
While the findings are significant, researchers caution that further work is needed to confirm and refine the estimates. Uncertainties remain regarding potential hydrogen loss during decompression and other chemical interactions within the core. Kei Hirose, a professor at the University of Tokyo who studies the Earth’s core composition, noted that previous research suggests the hydrogen content could be even higher, ranging from 0.2% to 0.6% of the core’s weight.
Understanding the origin and distribution of hydrogen is crucial for unraveling the mysteries of planetary formation and the emergence of life on Earth. This research provides a new perspective on the Earth’s deep interior and its role in shaping our planet’s history.
The-CNN-Wire
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Mindy Weisberger is a science writer and media producer, and her work has appeared in Live Science, Scientific American, and the magazine How It Works. She is the author of “Rise of the Zombie Bugs: The Surprising Science of Parasitic Mind-Control” (Hopkins Press).
