Earth’s core may contain up to 45 oceans’ worth of hydrogen, a groundbreaking study reveals. This estimate suggests that the planet formed from a gas-and-dust disk that was abundant in the universe’s lightest element. The research, recently published in Nature Communications, indicates that Earth’s water has likely been present since the planet’s formation, challenging previous theories that suggested water arrived later through impacts from comets and other icy bodies.
The core of Earth, primarily composed of iron, contains lighter elements that provide insights into the planet’s formation. Due to the core’s inaccessibility, researchers rely on computer simulations and high-temperature experiments using diamond anvil cells to mimic the extreme conditions at the center of the Earth.
Hydrogen, being a light and diffusive element, poses challenges in these experiments. However, a team led by Dongyang Huang from Peking University in China developed a method to accurately measure hydrogen content. By subjecting iron and hydrous silicate glass samples to high temperatures and pressures, the researchers were able to extract precise data on hydrogen’s presence in Earth’s core.
The results of the study suggest that hydrogen constitutes between 0.07 and 0.36 percent of the core by weight, equivalent to the amount of hydrogen in nine to 45 oceans’ worth of water. This significant finding implies that the hydrogen in Earth’s core originated during the planet’s initial formation, approximately 4.5 billion years ago.
The presence of hydrogen in the core played a crucial role in Earth’s evolution, contributing to the development of the planet’s magnetic field. This magnetic field, generated by an ancient geodynamo resulting from the crystallization of hydrogen, silicon, and oxygen within the core, is essential for Earth’s habitability.
The study’s findings shed new light on the origin of Earth’s water and the processes that shaped the planet’s early history. By unraveling the mysteries of Earth’s core composition, researchers are uncovering crucial insights into the planet’s formation and evolution.

