Earth’s core is leaking ancient helium and researchers are still scratching their heads as to why. They are surprised to find that our own planet was formed with this ancient isotope —- long counted on by futurists as a potential long-term source of safer-burning nuclear energy. The biggest surprise about this leakage, however, is that it indicates that our own Earth formed even earlier than thought.
The fact that Earth was able to accrete this Helium-3 so early in our solar system’s history indicates that our planet formed well inside the Sun’s early solar nebula. This shakes up the current paradigm about how close-in our Earth formed in relation to our young Sun, which has long been a subject of debate amount planetary formation theorists.
In a new paper just published in the American Geophysical Union (AGU) journal Geochemistry, Geophysics, Geosystems, researchers at the University of New Mexico posit that this rare isotope of helium gas, Helium-3, most of which formed during the big bang and was then gradually incorporated into Earth’s core as our planet formed.
“The solar nebula only lasted a short time — just a few million years,” the paper’s lead author Peter Olson, a geophysicist at the University of New Mexico, told me. “Helium-3 and other nebula gasses were incorporated into the Earth when it formed. This implies that Earth and terrestrial planets were in the process of forming very early in solar system history.”
The researchers posit that some 2,000 grams of helium-3 leak out of the Earth every year, about enough to fill a balloon the size of an average office desk. But until now, most geoscientists regarded our planet’s inner core basically as a closed system, with no mass exchange with the rest of the Earth. But Olson says that his team’s new models based on mass spectrometer measurements of helium-3 from volcanic basalts found in Iceland and Hawaii.
Helium-3 was dissolved into the basalt that formed Iceland and Hawaii, says Olson. Gas is extracted from those basalts and the helium-3 is measured in mass spectrometers, he notes.
“If you’ve been to Hawaii or Iceland, you may have inhaled a few molecules of primordial helium-3 from the core,” said Olson.
How could the core retain such helium-3?
The core offers a possible reservoir for helium-3 because it is less vulnerable to large impacts compared to other parts of the Earth system, is not subject to movements and outgassing from Earth’s giant tectonic plates, and has been in a liquid state over much of our planet’s history, the authors write.
Just how much of this helium-3 remains in the core?
Each year, about 2 kilograms of helium-3 escapes from Earth’s interior, mostly along the mid-ocean ridge system, say the authors. Geochemical evidence indicates the Earth has deep reservoirs of helium-3, but their locations and abundances remain uncertain, they note.
Earth’s mantle lost most of its helium-3 during and after our Moon’s impact formation, says Olson. It’s now being re-supplied from the core, he says.
What’s most puzzling about this core leakage?
“Why there is any Helium-3 coming out of the interior, now, after 4.56 billion years of Earth history,” said Olson.