A new study published in the journal Nature shows that the core internal of the planet Land For some years now, it has been experiencing a slowdown in relation to the planet’s surface.
According to him scientific discoverythe movement of core internal has been debated by the community scientific for two decades, and some research indicate that the inner core rotates faster than the surface of the planet.
The new one scientific investigation provides “unequivocal evidence that the inner core began to slow down around 2010, moving more slowly than the surface of the Land“.
“When I first saw the seismograms hinting at this change, I was perplexed,” said John Vidale, senior professor of Earth Sciences at USC, lead author of the study.
“But when we found two dozen more observations indicating the same pattern, the result was inescapable. The inner core had slowed down for the first time in many decades. Others scientists have recently advocated similar and different models, but our latest study provides the most compelling resolution.”
The relativity of recoil and deceleration It is considered that the core internal is reversing and receding relative to the surface of the planet because it is moving slightly slower rather than faster than Earth’s mantle for the first time in about 40 years. Relative to its speed in previous decades, the core internal is slowing down.
A solid sphere of iron and nickel
He core The inner core is a solid sphere of iron and nickel surrounded by the outer core of liquid iron and nickel. About the size of the moon, the inner core lies more than 3,000 miles beneath our feet and presents a challenge to researchers: it cannot be visited or seen. Scientists must use seismic waves from earthquakes to create representations of the movement of the inner core.
Vidale and Wei Wang of the Chinese Academy of Sciences used waveforms and repeated earthquakes in contrast to other research. The earthquakes Repeated seismic events occur at the same location to produce identical seismograms.
In this studythe researchers collected and analyzed seismic data recorded around the South Sandwich Islands from 121 repeat earthquakes that occurred between 1991 and 2023. They also used data from twin Soviet nuclear tests between 1971 and 1974, as well as repeat French and American nuclear tests from other studies. of the inner core.
Vidale said that the speed of deceleration of the core internal was caused by the agitation of the surrounding liquid iron outer core, which generates the Earth’s magnetic field, as well as by the gravitational pulls of the dense regions of the overlying rocky mantle.
The impact on the Earth’s surface
The implications of this change in the motion of the inner core for the surface of the Land They can only be speculated. Vidale said that the retreat of core internal can alter the length of a day in fractions of a second: “It is very difficult to notice, on the order of a thousandth of a second, almost lost in the noise of the churning oceans and atmosphere.”
Future research by USC scientists aims to chart the trajectory of the inner core in greater detail to reveal exactly why it is changing.
Video: stages of a science study
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