Rare Helium Gas Reported Leaking From Earth's Core

Most of this gas in the universe, called helium-3 is primordial and was created right after the Big Bang occurred about 13.8 billion years ago.

Some of this helium-3 will merge with other gas and dust particles in the nebula, a vast cloud thought to have led to the creation of the solar system.

The discovery that earth's core likely contains a large reservoir of helium-3 is further evidence to support the idea.

Earth forms within a developing solar nebula, not on its periphery or during its waning phase.

"Helium-3 is a natural wonder and a clue to Earth's history, that there are still large amounts of this isotope on earth's interior," said Peter Olson, a geophysicist at the University of New Mexico.

Helium-3 is an isotope of helium that has one neutron. It is a rare gas, where it only composes 0.0001% of the helium on Earth.

The gas comes from a variety of processes, such as the radioactive decay of tritium, a rare radioactive isotope of hydrogen.

But because helium was one of the earliest elements to exist in the universe, it's more likely that helium-3 originated in the Big Bang.

Previously, experts had known that about 2 kg of helium-3 came out of the Earth's interior each year.

But experts aren't sure exactly how much helium-3 comes from the core versus the mantle and how much helium-3 is in Earth's reservoirs.

To investigate this, the research team modeled helium abundance during two important phases of Earth's history, namely the early formation of planets, when it was still collecting helium, and after the formation of the Moon, when earth lost much of this gas.

Experts think that the Moon formed when a colossal object the size of Mars collided with Earth about 4 billion years ago.

The event will melt the Earth's crust and allow most of the helium inside the Earth to leak.

However, Earth did not lose all helium-3 at the time. Earth still harbors some rare gases, which continue to seep out of the planet's stomach.

According to experts, the core would be a good place for such a reservoir because it is less susceptible to large impacts compared to other parts of the Earth system.

The research team combined modern helium-3 leakage rates with models of helium isotope behavior. These calculations reveal that between 22 billion pounds and 2 trillion pounds of helium-3 are in the Earth's core.

The number is very large, indicating that the Earth formed in a solar nebula with a high concentration of gas.

However, since these results are based on modeling, the number is uncertain. The team of experts had to make a number of other assumptions to determine the magnitude of helium-3 on Earth.