A team of scientists has made a recent discovery that could explain the ebbs and flow of the magnetic field protecting all life on Earth.
The study published on May 6, Monday, discovered that molten iron alloys that contain silicon and oxygen form two liquids that have similar conditions as those within the core of the planet. The process is called immiscibility and the team compared it to vinaigrette in a salad.
"We observe liquid immiscibility often in everyday life, like when oil and vinegar separate in salad dressing," shared Sarah Arveson, a graduate student at Yale University. "It is surprising that liquid phase separation can occur when atoms are being forced very close together under the immense pressures of Earth's core."
Arveson is the lead author of the study published in the journal Proceedings of the National Academy of Sciences.
The Earth's Core As A Salad Dressing
The magnetic field is produced by convection that takes place within the outer core. The hot fluids are mostly well mixed together, but there is still a separate layer at the top where seismic waves travel more slowly compared to the rest of the outer core.
In their study, Arveson and colleagues reproduced the conditions within the Earth's outer core using laser-heated diamond-anvil cell experiments (to mimic the extremely high pressures beneath the surface) and computer simulations. They demonstrated two liquid layers: the first one was an oxygen-poor iron-silicon liquid and the other was an iron-silicon-oxygen liquid. The latter was less dense, which meant that it rose to the top and formed its own distinct layer.
The experiment, according to the researchers, is proof of the immiscible iron alloys that form layers at the outer core.
"Our study presents the first observation of immiscible molten metal alloys at such extreme conditions, hinting that immiscibility in metallic melts may be prevalent at high pressures," stated Kanani K.M. Leem an associate professor at Yale.
Understanding The Earth's Magnetic Field
The team claims that the study could offer a better understanding of the Earth's magnetic field, the planet's conditions back when it was still young, and how it evolved throughout history.