Earth’s structure is layered like an onion—from the crust we walk on, down through the mantle, to the swirling liquid outer core, and finally to the solid iron inner core at the very center.

Changes in core spin — though they can be tracked and measured — are all but imperceptible to people on Earth’s surface, Vidale said. When the core spins more slowly, the mantle speeds up.

Strong new evidence suggests that primordial material from the planet’s center is somehow making its way out. Continent-size ...

Earth’s inner core, a solid metal ball gyrating within the molten outer core, may be both slowing down and changing shape. Recent analyses of earthquake waves have suggested that around 15 years ago, ...

Zotov predicts Earth’s rotation may soon decelerate once again. If he’s right, this sudden speeding-up could prove to be just ...

As meteorites bombarded one another in Earth’s early history, a reservoir of these precious metals developed when the core formed about 4.5 billion years ago.

Scientists say they’ve confirmed Earth’s inner core has been slowing down. Here’s what it could mean — and why the topic has been the subject of fierce debate.

WASHINGTON, D.C. — Earth’s inner core, a solid metal ball gyrating within the molten outer core, may be both slowing down and changing shape. Recent analyses of earthquake waves have suggested ...

Earth's magnetic field yanks at this solid ball of hot metal, making it spin. At the same time, the gravity and flow of the fluid outer core and mantle drag at the core.

For a while, the scientists reported, the core’s rotation matched Earth’s spin. Then it slowed even more, until the core was moving backward relative to the fluid layers around it.