Scientists say they’ve confirmed a slowdown in Earth’s inner core rotation. Now what?

by | Jul 5, 2024 | Science

Sign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more.Deep inside Earth is a solid metal ball that rotates independently of our spinning planet, like a top whirling around inside a bigger top, shrouded in mystery.This inner core has intrigued researchers since its discovery by Danish seismologist Inge Lehmann in 1936, and how it moves — its rotation speed and direction — has been at the center of a decades-long debate. A growing body of evidence suggests the core’s spin has changed dramatically in recent years, but scientists have remained divided over what exactly is happening — and what it means.Part of the trouble is that Earth’s deep interior is impossible to observe or sample directly. Seismologists have gleaned information about the inner core’s motion by examining how waves from large earthquakes that ping this area behave. Variations between waves of similar strengths that passed through the core at different times enabled scientists to measure changes in the inner core’s position and calculate its spin.“Differential rotation of the inner core was proposed as a phenomenon in the 1970s and ’80s, but it wasn’t until the ‘90s that seismological evidence was published,” said Dr. Lauren Waszek, a senior lecturer of physical sciences at James Cook University in Australia.But researchers argued over how to interpret these findings, “primarily due to the challenge of making detailed observations of the inner core, due to its remoteness and limited available data,” Waszek said. As a result, “studies which followed over the next years and decades disagree on the rate of rotation, and also its direction with respect to the mantle,” she added. Some analyses even proposed that the core didn’t rotate at all.One promising model proposed in 2023 described an inner core that in the past had spun faster than Earth itself, but was now spinning slower. For a whi …

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[mwai_chat context=”Let’s have a discussion about this article:nnSign up for CNN’s Wonder Theory science newsletter. Explore the universe with news on fascinating discoveries, scientific advancements and more.Deep inside Earth is a solid metal ball that rotates independently of our spinning planet, like a top whirling around inside a bigger top, shrouded in mystery.This inner core has intrigued researchers since its discovery by Danish seismologist Inge Lehmann in 1936, and how it moves — its rotation speed and direction — has been at the center of a decades-long debate. A growing body of evidence suggests the core’s spin has changed dramatically in recent years, but scientists have remained divided over what exactly is happening — and what it means.Part of the trouble is that Earth’s deep interior is impossible to observe or sample directly. Seismologists have gleaned information about the inner core’s motion by examining how waves from large earthquakes that ping this area behave. Variations between waves of similar strengths that passed through the core at different times enabled scientists to measure changes in the inner core’s position and calculate its spin.“Differential rotation of the inner core was proposed as a phenomenon in the 1970s and ’80s, but it wasn’t until the ‘90s that seismological evidence was published,” said Dr. Lauren Waszek, a senior lecturer of physical sciences at James Cook University in Australia.But researchers argued over how to interpret these findings, “primarily due to the challenge of making detailed observations of the inner core, due to its remoteness and limited available data,” Waszek said. As a result, “studies which followed over the next years and decades disagree on the rate of rotation, and also its direction with respect to the mantle,” she added. Some analyses even proposed that the core didn’t rotate at all.One promising model proposed in 2023 described an inner core that in the past had spun faster than Earth itself, but was now spinning slower. For a whi …nnDiscussion:nn” ai_name=”RocketNews AI: ” start_sentence=”Can I tell you more about this article?” text_input_placeholder=”Type ‘Yes'”]
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