Earth’s Inner Core Is Changing Shape, Scientists Reveal
In a remarkable scientific breakthrough, researchers have discovered that Earth’s inner core is not as stable as once believed. A new study published in Nature Geoscience reveals that the planet’s innermost layer—a solid metal sphere about 70% the size of the moon—is undergoing shape changes over time.For decades, scientists have theorized that the inner core, composed mainly of iron and nickel, could deform as it spins. Now, using earthquake data spanning from 1991 to 2023, they have found the first concrete evidence of these deformations.
“It’s almost science fiction to visualize what’s happening on the surface of the inner core,” said Dr. John Vidale, lead author of the study and a professor of Earth sciences at the University of Southern California. “But seismic waves from powerful earthquakes have given us a way to peek inside.”
The Inner Core’s Mysterious Movements
In a surprising twist, scientists previously discovered that the inner core’s rotation slowed down around 2010 and even started spinning backward relative to the rest of the planet. Now, they’ve identified that its shape is changing as well.
These findings were made possible by analyzing seismic waves from earthquakes near the South Sandwich Islands. Subtle differences in these waves revealed deformations in the inner core’s surface, possibly caused by “landslide-like” movements or shifts in its topography.
What’s Causing the Changes?
Researchers believe that the molten outer core, which surrounds the solid inner core, may be exerting pressure and causing the inner core to shift and reshape slightly over time. This dynamic interaction between Earth’s core layers is crucial because it helps generate the magnetic field that protects our planet from solar radiation.
“The inner core is slowly growing as it solidifies, drawing material from the outer core,” explained Vidale. “Eventually, in billions of years, the entire core may become solid, which could lead to the loss of Earth’s magnetic field.”
Why It Matters
While these changes won’t affect daily life anytime soon, they offer critical insights into Earth’s long-term evolution. Understanding the inner core’s behavior helps scientists predict how the magnetosphere, which shields us from harmful space weather, might change in the future.
“This research adds a new layer to our understanding of the inner core,” said Dr. Yoshi Miyazaki, an Earth sciences professor at Rutgers University. “It’s not just about rotation anymore—the shape itself is evolving.”
Though the idea of Earth’s core shifting might sound like a plot from a sci-fi movie, for scientists, it’s a thrilling step forward in decoding the mysteries buried 4,000 miles beneath our feet.
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