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USC scientists have made groundbreaking discoveries about the nature of the mysterious inner core of the Earth, revealing for the first time that this 1,500-mile wide ball of iron and nickel is changing. .
The inner core of a planet was previously thought to be a hard, solid sphere. However, new research shows that when pressing liquid iron and nickel in the core outside the Earth, its edges are realized and softer than the actual changing shape.
“It is widely known that the melted outer core is a turbulent flow, but that turbulence has not been observed to destroy neighbors on human timescales,” said USC, who led the study. Professor John Vidale of Earth Sciences said. “The first thing we’re looking at in this study is the outer core that probably disrupts the inner core.”
Vidale said it is likely that the outer core is deforming the shape of the inner core, pushing 1km or 2km in the area that rubs with the force. These findings were published Monday in a study conducted with researchers from the University of China Science, Cornell University and the University of Utah.
When his team members embarked on their research, they were not expecting to document the structural changes in the inner nucleus of the Earth. Instead, they were focused on learning more about slowing down that spin.
Previous studies have shown that inner core rotation slows compared to outer crust rotation, causing minor changes in Earth rotation, which can subtly affect the length of the day. There is. These time changes are estimated to be a problem with milliseconds a year, but can accumulate over many years.
Vidale said he was busy studying graphs that recorded ground vibrations caused by seismic waves when one dataset “stood stand out from the rest.”
“Later I realized I was staring at evidence that my inner core was not solid,” he added.
His team was studying seismic data from 121 repeated earthquakes at 42 locations near the Southern Sandwich Islands of Antarctica that occurred between 1991 and 2024.
Repeated earthquakes are earthquakes of the same size and location. If a pair of repeated earthquakes occur while the inner nucleus of the Earth is in the same location while rotating, the scientists assume that the recorded seismic data is the same for both earthquakes.
However, the strange dataset that Vidale encountered ignored this logic and encouraged his team to recognize that the differences they observed are likely to be caused by changes in the shape of the inner core. Ta.
“We see these subtle differences,” he said. “And if not [caused by] Turning the inner core, the most likely possibility is that there is some deformation in the outermost soft inner core. ”
The scientific meaning of this revelation is not yet clear, but Vidale hopes that it will help researchers to solve further mysteries related to their inner core and lead to a better understanding of the Earth’s thermal and magnetic fields. Masu.
“I hope it has a broader meaning,” he said. “The reason we do this is because we want to solve the mystery, and the strangers and hard-liness who we can solve will make us happy.”
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