Earth’s inner core changing shape? Scientists reveal it may have 'deformed by over 100 meters'

A recent study has proposed that Earth's inner core too may not be as stable as previously thought

The Earth is continuously changing, with constant transformations occurring both on its surface and within its core. The movement of tectonic plates, climate shifts, and the drifting of the magnetic poles all play a part in the planet's ongoing evolution.

A recent study has proposed that Earth's inner core too may not be as stable as previously thought. The findings suggest that the inner core is undergoing structural changes, which could influence its rotation and potentially cause a slight change in the length of a day.

These changes may be occurring at the boundary where the solid inner core meets the extremely hot, liquid metal of the outer core.

The Mysterious Inner Core

Understanding Earth's internal structure may help understand the significance of this finding. Below the crust, where life exists, the planet is made up of layers-the mantle, followed by the molten, iron-rich outer core, and at the center, the solid inner core. While the outer core has been known to be volatile, its influence on the inner core within human timescales has been uncertain.

Understanding how the inner core works is crucial for understanding the magnetic field that shields our planet.

The Earth's core acts as the planet's driving force, generating a magnetic field that protects life from harmful solar radiation.

The inner core spins independently of the liquid outer core and the rest of the Earth. Without this motion, Earth would become desolate, similar to Mars, which lost its magnetic field billions of years ago.

Uncovering the Secrets Through Seismic Waves

The study featured in the scientific journal Nature Geoscience was initially conducted to explore why the inner core appeared to slow down to a rate slower than Earth's rotation before picking up speed again in 2010.

The Earth's interior is an incredibly mysterious area. The core is situated roughly 4,000 miles beneath the surface, and despite extensive attempts, scientists have been unable to reach it.

In an effort to unlock its secrets, some researchers study the shockwaves generated by earthquakes as they move through the Earth.

By observing how the waves travel, scientists can determine the types of materials they pass through, including in the inner core, which helps to form a better understanding of what lies beneath the Earth's surface.

The new analysis examined seismic wave patterns from earthquakes that occurred in the same location between 1991 and 2023. This data helped reveal how the inner core has been changing over time.

Professor Vidale, an earth scientist at the University of Southern California, found additional evidence supporting the theory that the inner core slowed down around 2010 during those years.

However, his team also uncovered evidence that the inner core's shape is changing.

Though the inner core is generally thought to be spherical, Prof. John Vidale, who led the research, believes its edges may have deformed by over 100 meters in some areas.

This change seems to be occurring at the boundary between the inner and outer core, where the inner core is close to its melting point. The movement of the liquid outer core, along with the pull from an uneven gravity field, could be causing this deformation.

What Do the Researchers Say About the Inner Core?

Prof. Vidale's research is part of ongoing global investigations by experts examining and debating the processes occurring in the Earth's core.

"In science, we generally try to look at things until we understand them," says Prof. Vidale.

"In all likelihood, this finding doesn't affect our daily lives one iota, but we really want to understand what's happening in the middle of the Earth," he adds.

It's possible that these changes are linked to alterations in Earth's magnetic field.

"The magnetic field has had jerks at various times in the past few decades, and we'd like to know if that is related to what we're seeing at the inner core boundary," he said.

Prof Vidale urged caution about hyping the findings into ideas that the core is going to stop rotating any time soon.

He also added that there are still lots of uncertainties.

"We're not 100% sure we're interpreting these changes correctly," saying that the boundaries of scientific knowledge are always changing and, like many if not all researchers, he has been wrong in the past.