High-temperature and high-pressure experiments to simulate the core of the young Earth demonstrate for the first time that hydrogen can bond strongly with iron in extreme conditions. This explains the significant presence of hydrogen in the Earth’s core that arrived as water from bombardments billions of years ago.
Using seismic data, researchers have determined that the Earth’s core is primarily made of iron, but its density, in particular that of the liquid part, is lower than expected.
This led researchers to believe that there must be an abundance of light elements mixed with the iron. Through laboratory experiments, they discovered that when water meets iron, most of the hydrogen dissolves into the metal while the oxygen reacts with iron and goes into the silicate materials. This explains the apparent lack of ocean water. Hydrogen is said to be iron-loving, or siderophile.
“This finding allows us to explore something that affects us in quite a profound way,” said Professor Kie Hirose, the team leader. “That hydrogen is siderophile under high pressure tells us that much of the water that came to Earth in mass bombardments during the formation might be in the core as hydrogen today. We estimate there might be as much as 70 oceans worth of hydrogen locked away down there. Had this remained on the surface as water, the Earth may never have known land, and life as we know it would never have evolved.”
https://phys.org/news/2021-05-hydrogen-earth-core-oceans.html