A new study shows that the inner core changed shape in just a few decades, challenging previous assumptions and revealing hidden dynamics deep within Earth.

Scientists of course cannot cut into Earth and directly observe its insides. Instead, their knowledge is inferred from the vibrations generated by earthquakes that pass through the planet. The speed and the direction of the seismic vibrations change depending on the density and the elasticity of the rocks.

Researchers found evidence that the Earth's inner core is changing shape, suggesting unseen processes affecting its movement over time.