Scientists Say Earth’s Mysterious Inner Core Is Changing Shape
Scientists have found evidence that Earth’s inner core is changing shape. Recent research indicates the inner core, traditionally thought to be a solid sphere, may be deforming, with some areas changing in height by 100 meters or more.Key points about the Earth’s inner core and the new research:
Composition and location The inner core is a hot, solid sphere mainly made of iron, surrounded by a liquid metal outer core, located approximately 3,000 miles beneath the Earth’s surface.
How it was studied Because the inner core is impossible to observe directly, scientists analyze seismic waves from earthquakes to understand its properties.
What the study revealed Scientists discovered the inner core’s surface is dynamic and changing shape. The inner core may undergo viscous deformation, causing changes in its shape and shifts at its shallow boundary.
Why this is happening The liquid flow of the outer core and gravitational irregularities may be causing the inner core to deform. Density variations or convective flow in the outer core could also be factors.
Why it matters Understanding the dynamics of the Earth’s core is crucial because the core generates a magnetic field that shields the planet from harmful solar radiation. The changes in the core’s shape may provide insights into the forces that drive the magnetosphere.
The study, published in Nature Geoscience, analyzed seismic wave patterns from earthquakes between 1991 and 2023 to understand how the inner core evolves. The research team, led by Professor John Vidale, also found evidence that the inner core slowed down around 2010 and is now rotating in the opposite direction compared to the rest of the planet.
Recent studies indicate that Earth’s inner core is undergoing changes in shape and rotation. These findings, published in Nature Geoscience, challenge long-held beliefs about the inner core’s stability and composition.
Shape Alterations: Evidence suggests the inner core’s outer boundary has noticeably changed shape over the past few decades. Some areas may have deformed by 100 meters or more. The surface of the inner core appears to be dynamic, changing shape as it rotates.
Rotation Changes: The inner core, which once spun faster than the Earth itself, began to slow its rotation around 2010. It is now rotating in the opposite direction compared to the rest of the planet.
Seismic Wave Analysis: Researchers analyzed seismic waves from earthquakes between 1991 and 2023 to understand these changes. These waves, which penetrate the Earth’s center, provide clues about the materials they encounter, including the inner core.
Composition and Dynamics: The Earth consists of an outer crust, a semi-liquid mantle, a molten outer core, and a solid inner core. The inner core, a heated, solid sphere composed of metal, is encased by a liquid metal outer core. The liquid flow of the outer core, combined with the uneven gravitational field, may be causing the inner core to deform.
Impact and Significance: The inner core plays a vital role in generating a magnetic field that shields the planet from harmful solar radiation, making its dynamics essential for sustaining life. Changes in the inner core could affect the length of the day and Earth’s magnetic field.
Expert Opinions: Professor John Vidale, who led the study, noted the changes might be connected to changes in Earth’s magnetic field. Professor Hrvoje Tkalcic from the Australian National University said the study presents “an interesting concept that should be explored further,” potentially allowing for more informed estimates of the inner core’s viscosity.
Future Implications: The interaction between the inner and outer core is believed to be the cause of these structural changes. Understanding these dynamics may lead to a better understanding of Earth’s thermal and magnetic fields.
