In a groundbreaking new study, researchers from Peking University’s SinoProbe Lab at School of Earth and Space Sciences employed seismic waves from earthquakes to examine the Earth’s inner core. They discovered that the core had ceased spinning.
Astonishingly, Earth’s core may have also reversed direction, something it appears to on cycle approximately every 60-70 years. This discovery may answer questions about climate and geological phenomena that occur within the same time frame, ones that impact life on Earth.
Nestled at the center of our planet is a solid metallic core that’s about three-fourths as big as the Moon. Scientific research has proven Earth’s inner core travels at different directions and speeds, and rotates independently from our planet due to being encased in liquid material. There are still unanswered questions such as whether its velocity changes over time or not.
The Earth’s core lies approximately three thousand miles beneath the surface and experiences levels of heat comparable to the Sun’s surface. This remoteness means the core remains one of its most enigmatic realms on Earth. It impacts processes that make Earth possible to live on, such as our protective magnetic field, the length of days, and even climatic patterns. Despite being difficult to explore, scientists are determined to uncover its secrets.
Scientists Yi Yang and Xiaodong Song said about their research, “There are two major forces acting on the inner core. One is the electromagnetic force. The Earth’s magnetic field is generated by fluid motion in the outer core. The magnetic field acting on the metallic inner core is expected to drive the inner core to rotate by electromagnetic coupling. The other is gravity force. The mantle and inner core are both highly heterogeneous, so the gravity between their structures tends to drag the inner core to the position of gravitational equilibrium, so-called gravitational coupling.”
“If the two forces are not balanced out, the inner core will accelerate or decelerate,” they continued. “Both the magnetic field and the Earth’s rotation have a strong periodicity of 60-70 years. We believe that the proposed 70-year oscillation of the inner core is driven by the electromagnetic and gravitational forces.”
Song and Yang are trying to gather data and test models that would confirm where the changes from, looking back at seismic wave data since the 1960s. They looked for events where more than one earthquake had “identical waveforms at common receivers.” By doing this they have come to believe the core stopped spinning around 2009, and before that in the 1970s.
“Our results further support the inner-core rotation, and more interestingly, reveals the multidecadal pattern of the rotation,” they said.
They have expectations about how the core with rotate over the coming years and will develop new models that will hopefully provide more answers.
