For decades, scientists have puzzled over the "density deficit" in Earth's core, a discrepancy between the expected density of a solid iron core and the lower density observed through seismic measurements.

The Discovery

A recent study published in Nature Communications suggests that this deficit could be explained by the presence of vast amounts of hydrogen trapped within the core, reducing its overall density. The research also offers new insights into the origin of liquid water on Earth.

The Experiments

The researchers conducted experiments simulating the extreme conditions present in the core during Earth's formation, heating iron metal with lasers to a fully molten state, reaching temperatures up to 8,700°F and pressures millions of times greater than those on Earth's surface. They then searched for the presence of hydrogen in nanostructures made of silicio and oxygen, estimating that the hydrogen percentage in the core is between 0.07 and 0.36 percent, equivalent to 9-45 times the amount of hydrogen present in all of Earth's oceans.

Implications for the Origin of Water

The study supports the hypothesis that most of Earth's water comes from the early stages of planet formation, rather than from comets arriving later. However, the researchers point out that hydrogen alone may not fully explain the density deficit, suggesting that other light elements or compounds, such as water itself, may also contribute.