How did Earth’s inner core freeze solid? Rost9/Shutterstock
A high concentration of carbon within Earth’s inner core could explain a long-standing mystery about how the deepest part of our planet froze solid – a process that kick-started the magnetic field protecting life on the surface.
Earth’s inner core presents a paradox for geophysicists: it first formed as a massive liquid ball of mostly iron, then began to solidify within the last billion years. In order for that freezing process to start in a pure iron object, it would have had to cool by at least 700 kelvin in…
Article amended on 19 November 2024
We clarified the proportion of carbon needed for freezing under 250 K of cooling
