Mysterious ‘Doughnut’ Discovered in Molten Metal Inside Earth’s Core

Earth’s core, a massive ball of liquid metal located about 2,890 kilometers beneath the surface, has revealed a surprising new feature. Scientists have discovered a ring-like structure in the outer core, which resembles a doughnut and runs parallel to the equator, according to a study published in the journal *Science Advances*.

Co-author of the study, Prof. Hrvoje Tkalčić, a geophysicist at the Australian National University, explained that current technology does not allow us to directly reach the Earth’s core. Instead, the team relied on seismic waves generated by large earthquakes to study the inner layers of the planet. They analyzed how these waves traveled through the Earth, comparing data from detectors located near the poles with those closer to the equator.

The researchers observed that seismic waves slowed down near the top of the outer core, just below the mantle. “By understanding the geometry of the wave paths and how they move through the outer core, we were able to reconstruct their travel times through the Earth,” Tkalčić explained.

They discovered that the seismic waves decelerated in an area that mathematically forms a torus, which resembles a doughnut shape. Tkalčić noted that the waves detected closer to the poles moved faster than those near the equator.

Understanding the outer core is crucial, Tkalčić emphasized, because it plays a key role in generating Earth’s magnetic field. This magnetic field protects the planet from the constant bombardment of charged particles from the sun. The movement of molten iron and nickel in the core creates electric currents that function like a “giant dynamo,” which generates and sustains the magnetic field. The presence of this dynamo has long puzzled scientists, as it is unique to Earth compared to other planets.

Earth’s core is slightly larger than Mars, leading Tkalčić to describe it as “a planet within our own planet.” While the exact size of the doughnut-shaped structure remains uncertain, it likely extends a few hundred kilometers beneath the core-mantle boundary.

The structure is thought to be composed of lighter chemical elements, such as silicon, sulfur, oxygen, hydrogen, or carbon.