Earth’s Inner Core Is Changing Shape, And Scientists Are Puzzled As To Why This Is Happening
Not only is Earth’s inner core spinning and growing, but it’s also changing shape, according to new research. Our planet’s inner core is a hot, solid ball of iron that is roughly 1,500 miles wide.
Scientists have found evidence of deformation at its boundary with the liquid outer core. They believe that interactions between the Earth’s inner and outer cores are causing the inner core to change its shape.
Since it’s deep in the center of the Earth, scientists are unable to access the inner core, so they use other sources of information to understand it.
Knowing how the Earth’s core works is important because it improves our understanding of the magnetic field that protects the planet.
The research team analyzed the seismic waves from 121 earthquakes that occurred between 1991 and 2023.
The waves had passed through the inner core as they traveled to North America from the South Sandwich Islands in the southern Atlantic Ocean. They compared the earthquakes to determine if their wave signals had changed over the years.
They found variations in some of the waves that pointed to deformations in the inner core. Seismic waves that traveled through the core’s outermost region were the ones that showed changes, indicating that the shifts were taking place around the outer boundary of the inner core.
“This is kind of the first time we’ve seen the evidence for this kind of motion,” said John Vidale, the lead author of the study and a seismologist at the University of Southern California.
“The surface of the inner core is moving around in ways we hadn’t detected and still don’t understand very well.”
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The study follows after previous research conducted by the same team about how the inner core’s spin has been slowing down.
Last summer, they proposed that the rotating core changes its speed in a cycle—it alternates between spinning faster and slower than the Earth’s surface.
They were originally trying to figure out why the inner core decelerated to a pace slower than the Earth’s rotation before speeding back up again in 2010.
However, some experts disagreed with the idea. They argued that fluctuations in the core’s shape rather than changes in speed could explain the differences in the core’s spin. Now, the current study suggests that the core’s spin is due to both changes in speed and shape.
Fortunately, our lives are not really impacted by what’s going on deep beneath the Earth. The researchers hope their work can lead to more discoveries about the inner core.
“We hope it has broader implications,” said Vidale. “The reason we do this is we like to solve riddles, and the stranger and harder the riddle that we can solve, the happier we are.”
The details of the full study were published in the journal Nature Geoscience.
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