The Earth's core is important because it generates the planet's electromagnetic field - which seems to be weakening.

BBC: Planet Earth

Specifically, what the scientists have found is that the iron adopts a crystalline structure, like a diamond, in the Earth's core.

BBC: Planet Earth

So clear are the steaming pools that to stare down into them is like staring down into a cave that leads to the earth's core.

FORBES: Magazine Article

They constructed levees that, in all but the most extreme circumstances, overcame gravity's force and held back hundreds of millions of tons of water that would otherwise seek a route to the Earth's core via New Orleans.

NPR: Defying Gravity, and Odds, in New Orleans

The research could help test simulations of how the outer, fluid core generates the Earth's magnetic field, which shields our planet and the teeming life on it from harmful cosmic rays.

BBC: NEWS | Science/Nature | Earth's core runs ahead of crust

The inner core, made of very pure, solid iron, rotates along with the outer core, dragging the Earth's magnetic field with them.

BBC: Earth's wobbles reveal deep secrets

The planet has no internal magnetic field, which might be due to its core failing to circulate in the way the Earth's does.

ECONOMIST: Planetary science