Earth's inner core may have changed shape, say scientists

Scientists believe the Earth's inner core may have undergone a change in shape over the past 20 years.

The inner core is typically considered to be spherical in shape, however, its edges could have deformed by 100 meters or more in height, as suggested by research led by Professor John Vidale.

Earth's core is the core of our planet's life-support system, generating a magnetic field that shields life from the Sun's hazardous radiation.

The Earth's inner core rotates independently of its liquid outer core and the rest of the planet. If this movement did not occur, the Earth would cease to exist and would become similar to Mars, which lost its magnetic field billions of years ago.

The change in shape may be occurring at the point where the edge of the solid inner core meets the extremely hot liquid metal of the outer core.

The research is published in Nature Geoscience, a scientific journal. The researchers sought to understand why the inner core had slowed down to a slower pace than the Earth's rotation, only to speed up again in 2010.

Comprehending the Earth's core is crucial to understanding the magnetic field that shields the planet, and whether it could lose strength or cease altogether.

The inside of our planet remains a profoundly enigmatic region. The core is situated approximately 6,400 kilometers from the Earth's surface and, despite the most concerted efforts, scientists have yet to successfully access it.

Scientists are attempting to uncover the mysteries of earthquakes by analyzing the shockwaves that propagate through the Earth.

The way seismic waves travel reveals the type of material they have passed through, including in the Earth's inner core, and helps create a picture of what lies beneath our feet.

A new study examined seismic wave patterns from earthquakes that recurred in the same location between 1991 and 2023. This provided insight into how the inner core is evolving over time.

Professor Vidale, an earth scientist at the University of Southern California, discovered additional evidence to support the hypothesis that the Earth's inner core slowed down around 2010.

Researchers have also discovered evidence of the inner core's changing shape.

It seems to be occurring at the boundary between the inner and outer core, near the inner core's melting point. The liquid flow of the outer core and the uneven gravitational pull may cause the area to deform.

Dr. Hrvoje Tkalcic from the Australian National University, who was not involved in the study, stated that the paper offers "an intriguing idea that warrants further investigation".

He stated that it would enable researchers "to make more informed estimates of some significant material properties, such as the viscosity of the inner core, which is one of the least understood quantities in contemporary science".

The liquid outer core will gradually solidify to form the solid inner core, but this process will take billions of years to be fully completed.

This would likely mark the end of life on Earth, but by that point the planet would have already been engulfed by the Sun.

Professor Vidale's research is part of ongoing investigations by experts globally, who are examining and debating the dynamics at the core.

"We generally aim to study phenomena until we grasp their underlying principles," Prof Vidale says.

He says this discovery probably won't have any impact on our daily routines, but we're still very curious to know what's happening at the Earth's core.

There is a possibility that these changes are associated with fluctuations in the Earth's magnetic field.

The magnetic field has experienced sudden changes at various points over the past few decades, and we would like to determine if this is connected to the current activity at the boundary of the inner core.

Professor Vidale cautioned against exaggerating the significance of the research findings, emphasizing that they do not imply the core will cease rotating anytime soon.

He also emphasized that there are still many uncertainties.

"We're not 100% certain that we're accurately interpreting these changes," stating that the limits of scientific knowledge are always evolving, and like many, if not all, researchers, he has previously been mistaken.

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