Study Suggests

When we think of Earth’s core, most of us imagine a fiery, molten sphere at the center of our planet. But recent discoveries by scientists at the Australian National University have uncovered something unexpected deep beneath our feet: a doughnut-shaped region in Earth’s liquid outer core that could change how we understand the dynamics of our planet’s magnetic field.

The Discovery: A Hidden Structure in Earth’s Core

This newly discovered region is located thousands of kilometers beneath the surface, confined to low latitudes and sitting parallel to the equator. What makes this discovery so remarkable is that it had remained hidden until now, despite decades of research into Earth’s core.

The Earth’s core consists of two layers: a solid inner core and a liquid outer core, both surrounded by the mantle. The doughnut-shaped structure was found at the top of the outer core, right where it meets the mantle. Seismologists detected slower seismic waves in this region compared to the rest of the outer core, indicating that the structure has unique properties.

A New Way to Study Seismic Waves

Traditional methods of observing seismic waves generated by earthquakes usually focus on signals within the first hour after the event. However, the ANU scientists took a different approach. By analyzing the similarities between waveforms many hours after the earthquake origin times, they managed to reconstruct the paths of the waves through the Earth and reveal the existence of this doughnut-shaped region.

Professor Hrvoje Tkalčić, a geophysicist and co-author of the study, explained that the region has low seismic speeds, which suggests a high concentration of light chemical elements. These elements, along with temperature differences, likely contribute to the unique dynamics within the outer core.

Implications for Earth’s Magnetic Field

The discovery of this structure has significant implications for our understanding of Earth’s magnetic field. The liquid outer core is predominantly made of iron and nickel, and its movement generates the magnetic field that protects Earth from harmful solar radiation. Knowing more about the composition and dynamics of the outer core, including the role of light elements, is crucial for predicting the future behavior of the magnetic field.

“The magnetic field is a fundamental ingredient that we need for life to be sustained on the surface of our planet,” said Professor Tkalčić. “Our findings could promote more research about the magnetic field on both Earth and other planets.”

This research, published in Science Advances, opens new avenues for studying the deep Earth and highlights the importance of interdisciplinary efforts in solving the mysteries of our planet’s core.