The spinning core at Earth’s center may have recently stopped spinning, relative to the surface, as part of a seven-decade cycle, scientists have said.
A study has found that the inner core, which is the size of Pluto, could have stopped spinning around 2009.
This could be possible because the inner core is mostly a ball of solid iron floating in a liquid outer core, so its rotation isn’t necessarily tied to that of the rest of the planet.
The scientists also said that the inner core may have started spinning in the opposite direction instead.
If so, there is probably something going on with the magnetic and gravitational forces that cause the core to spin.
The research could help better understand how changes in the core can impact things on Earth’s surface, such as day length and navigation.
The seismic waves of earthquake that passed through the inner core of the planet were analyzed as part of the study.
Tracking waves found there had “little change over the past decade” in trajectories that previously showed “significant temporal shifts”.
The process is part of an “oscillation of about seven decades”, reports the study.
Peking University scientists in China believe that “this globally consistent pattern suggests that the rotation of the inner core has recently come to a halt”.
They wrote: “We compared this recent pattern to Alaska seismic records of the South Sandwich Islands doublets dating back to 1964 and it appears to be associated with a gradual reversal of the inner core as part of an oscillation of about seven decades, with another turning point in the early 1970s.”
Their observations, published in the journal Nature Geoscience, provide further evidence of “dynamic interactions” between the Earth’s different layers that can influence magnetic field and surface changes.
The Earth’s core is said to be a solid ball that has a radius of about 800 miles and a temperature similar to the surface of the sun.
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Previous research has shown that the core is separated from the rest of the planet by a liquid metal outer core, allowing it to spin independently and at a different rate from the rest of the Earth.
Other scientists have noted the research, but believe it may take several years before they can determine if it is accurate.