LOS ANGELES (KTLA) – Researchers at the University of Southern California say they have unraveled the mystery of why the inner nucleus of the Earth is slowing down and gradually changing the length of the day.
For decades, scientists have assumed that Earth’s moon-sized core was made of solid iron and nickel, trapped with the planet’s surface. However, in 2010, for the first time in documented history, it began to show signs of slowing down.
“When I was analyzing decades of earthquake records, one dataset of seismic waves stood out strangely from the rest,” said John Vidale of the USC Dornsife College of Letters, Arts and Sciences. . “Later I realized I was staring at evidence that my inner core was not solid.”
This study analyzed seismic data including 121 repeat earthquakes at 42 locations near the Southern Sandwich Islands of Antarctica from 1991 to 2024. Researchers looked at waveforms from receiver stations in Alaska and Canada.
According to the university, the data shows “non-characteristic properties” that the team has never seen before, with the inner core of the Earth changing shape and movement, initially faster than the rest of the planet. , indicating that it is later.
“The melted outer core is widely known to be turbulent, but that turbulence has not been observed to destroy neighbors on human timescales,” Bidale said. “The first thing we’re looking at in this study is the outer core that probably disrupts the inner core.”
USC researchers said the findings shed light on why the length of the day is not constant, usually measured at 24 hours or 86,400 seconds. Scientists believe the day continued 600 million years ago, just 21 hours ago.
Other factors include the magnetic field of the Earth, the effects of the sun and moon tides, and the distribution of masses on planets.
The study was published on Nature Geoscience on Monday.
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