What is happening in the very center of our planet is largely a mystery.
The truth is that no human has ever gone through the crust or drilled deep enough to penetrate the Earth's mantle, let alone its liquid iron core, so we don't know what types of interactions take place there.
The core of our planet is far beyond our technological reach – at least for the time being – and yet, thanks to clever theoretical models, scientists have found answers to some of the mysteries beneath our feet.
New research is now showing that Earth's molten core can actually lose iron into the upper mantle, which is a thousand degrees colder than the liquid core.
For decades, scientists have debated whether the core and mantle exchange physical material.
(L. O'Dwyer Brown, Aarhus University)
The powerful magnetic field of the Earth and its electric currents certainly mean that there is a lot of iron in the core. In addition, samples of mantle rocks ejected to the surface also show significant iron contents, leading some to assume that the material comes from the core.
To get some idea of whether this is possible, the researchers conducted laboratory experiments showing how iron isotopes move between different temperature regions at high pressures and temperatures.
Using this information to create a model, the group's results show that heavy isotopes of iron can migrate from the hotter core of the Earth into the colder mantle. While the light iron isotopes will do the opposite and go from cold to hot back to the core.
These results are still theory, but they can teach us something important about how the interior of our planet works.
Using computer simulations, the authors were even able to show how this core material could travel all the way to the Earth's surface, with heavier isotopes moving upward in a hot mantle plume similar to those found in Samoa and Hawaii – a possible signature of a 'leaking' core Earth.
New simulations only show that high temperature and pressure leakage from the core to the mantle is possible, and this may explain why mantle rocks contain much more iron than meteorites: in short, iron liquid comes from the heart.
The study was published in the journal Nature Geoscience.
Sources: Photo: NASA
