An Immense Reserve Of Hydrogen Would Be Buried In The Heart Of Our Planet

When we approach the subject of energy transition, hydrogen comes up very often in debates and in the media. And for good reason, if it is produced ecologically (green hydrogen), it is a powerful energy vector, which could, in the long term, decarbonize our most polluting industries and be exploited by the automobile industryeven if for the moment, only Toyota and BMW have set their sights on this molecule.

Here, we are not going to approach hydrogen from an industrial prism, but from a geophysical angle. A study published in the journal Nature Communications on February 10, 2026 reported a staggering discovery: the largest stock of hydrogen on the planet is stored deep in the earth’s core. We are talking about a monumental quantity, up to 45 times the mass of all our oceans combined, or approximately 1,350 to 6,750 trillion tons. As it is trapped at a depth of 2,900 km, it is obviously impossible to drill down to this deposit to hope to extract even the slightest gram.

So why is it so important? Because this reservation is proof that the theory of the great late bombardment would have played only a secondary role in the history of the appearance of water. This states that approximately 4.1 to 3.9 billion years ago, the Earth would have been riddled with icy comets and asteroids which would have brought the first water molecules to our planet. An external contribution which would then have been only a small drop of water, since our planet already had in its bowels this gigantic reservoir.

Hydrogen: the missing piece of geophysics

In order to validate their theory without having to descend to a depth of 2,900 km, the team of Dongyang Huang, from Peking University, had to be inventive. Since it is physically impossible to pay a quick visit to the Earth’s core, they chose to bring the earth’s core to them; at least by simulating its characteristics.

To do this, they used a diamond anvil cella device that harnesses one of nature’s hardest minerals to generate titanic pressures. The pressure (P), in physics is defined by the ratio of the normal force (F) on the area of the contact surface (S). So, by applying this equation (P=F/S) and by exerting a moderate force on the tip of an extremely fine diamond (a few tens of microns), the pressure obtained at the point of contact is titanic.

By placing a sample of iron and hydrogen into the diamond anvil cell, researchers have managed to recreate the hell from the depths of our planet. The sample, confined in a tiny hole drilled in the center of a metal gasket, was compressed to 111 gigapascals, or more than a million times atmospheric pressure.

To complete the simulation, the natural transparency of the diamond made it possible to use an infrared laser to heat the mixture to 5,100 kelvins. Under these conditions, the chemical properties of the metal have mutated; the iron has been transformed; in liquid form, it dissolved the hydrogen, incorporating it into its atomic structure and thus changing its density. Since the hydrogen atom is the lightest element in the periodic table, its presence within the much heavier iron lattice reduces the overall mass per unit volume.

They thus solved a first enigma dating from the 1950s: the density deficit of the earth’s core. Since that time, seismologists have observed that waves traveling through the center of the Earth have a different speed than they would have if they were propagating in an iron-nickel alloy, the main elements constituting the core (90% iron, 10% nickel).

In wave physics, the speed depends on the density and elasticity of the medium; however, the core was found to be approximately 10% too light compared to the calculations. A light element was missing from the alloy to explain why the Earth’s core was not as dense as expected: this element was therefore hydrogen, which is lodged in the interstices left by the large atoms of iron and nickel.

The origin of water: a scientific revolution

Second dogma that researchers have just shaken up with this experiment: the exogenous cometary contribution. By proving that liquid iron can absorb enormous amounts of hydrogen under high pressure, the team demonstrated that the early Earth already had stored its own water reserves internally upon formation.

In fact, hydrogen being one of the two fundamental constituents of the water molecule (H₂O), its capture by iron removed it from spatial evaporation to restore it later, via volcanism, in the form of water vapor filling our oceans. Even if the comets did make a small contribution through the large late bombardment, the overwhelming majority of planetary water is endogenousand it is this reservoir which allowed life to appear on its surface approximately 3.8 to 3.5 billion years ago.