The Earth is like a giant balloon filled with helium. Sadly, it seems to be leaking. According to new research every single year up to 2,000 grams of the helium-3 isotope leak from the Earth’s core. Most of it comes from the time of the Big Bang and it got inside the planet when it was born.
Helium-3 is an extremely rare isotope of helium which can be found on the surface of the Earth only in very limited quantities. It comes from truly ancient times as the majority of it was created during the Big Bang itself. One place where it isn’t created is the Earth’s core. So, the question is, how did it get there? Some minerals in the Earth’s crust may be a source as it can be created in them as a result of radioactive decay. But it can also leak from the Earth’s core.
Geophysicist Peter Olson from the University of New Mexico and his colleagues claim that the main source of helium-3 on the Earth’s surface is the Earth’s core. But at the same time, helium is one of the oldest elements in the Universe. The majority of it comes from the Big Bang and that is also true for the it’s isotope helium-3. Currently, the majority of helium-3 can be found in nebulas.
So, how did it get into the Earth’s core? When the planets of the Solar system were being born the absorbed the material in the nebula around it. So, if the Earth’s core were to have a lot of helium-3 as Olson and his coworkers claim the Solar system would have to be born in the core of a full-blooded nebula – a stellar nursery. Not at its edge or when the nebula was slowly coming to the end of its life.
According to Olson and his team every year about 2,000 grams of helium-3 leak from the Earth’s core. That would allow you to fill a balloon about the size of a table. He also says this is a miracle of nature and a song from ancient times that tells us that deep beneath us there is still a lot of helium-3 from the very dawn of the Universe.
Olson’s team modeled this on top of the known scenarios about how the Earth and the Moon were born. When the protoEarth collided with the protoplanet Theia the Moon was created but also the Earth’s crust melted. This means the Earth balloon popped and the majority of the helium is gone. But there is still plenty there and it leaks.
The researchers took models of helium-3’s behavior into consideration and calculated that there should be roughly 10 Tg (Teragrams) to 10 Pg (Petagrams) of this isotope in the Earth’s core at this time. This seems to indicate that Earth was born in the center of a nebula full of matter with helium-3. To confirm these assumptions we could search for other gases from the original nebula that could be leaking similarly to helium-3. Perhaps hydrogen?