The Earth’s inner core may reflect its rotation


why does it matter: There are many mysteries related to the Earth’s core. One has to do with seismic fluctuations over the past several decades. Some scientists believe they are evidence of changes in the rotation of the inner core, but others disagree on their timing. Surface effects are likely to be negligible.

New study She suggests The Earth’s inner core has recently stopped rotating and is changing direction. The changing circulation may be behind slight fluctuations in day length from year to year.

In the January 2023 issue of Nature Geoscience, researchers Xiaodong Song and Yi Yang of Peking University of China claimed The planet’s inner core stopped rotating relative to the other layers around 2009. Later, the Earth’s interior, about 3,100 miles below our feet, made of hot iron and the size of Pluto, could rotate independently of the mantle and crust due to a liquid outer core. that surround it.

The researchers said that the inner core began to reverse its rotation after stopping and that this process is repeated approximately every 35 years. The last reversal occurred in the early 1970s. Next could be in the mid 40’s.

The study involved measuring seismic waves traveling through the Earth. These ripples date back to 1964 and were created by earthquakes and nuclear explosions. Waves that showed significant temporal changes in the early 1990s showed relatively little variation over the past decade, which could indicate that the core’s rotation has paused. The researchers found similar data from the early 1970s, and the data relates to changes in the length of the day.

John Fedel, a seismologist at the University of Southern California, disagrees. The inner core is believed to oscillate every six years based on data from nuclear explosions from the late 1960s to early 1970s. Other geophysicists have several theories, but Vidal doesn’t think any models adequately explain all the data.

One theory claims that the inner core moved significantly between 2001 and 2013 but has not moved since. In his research, Australian National University geophysicist Hrvoje Tkalczyk claimed that the core cycles back and forth every 20 to 30 years rather than changing in one direction every 35 years.

However, he also doubts the accuracy of all proposed theories. Seismic data provides only limited information about what is happening inside the Earth. Other theories posit that the inner core may have another core within it. Therefore, scientists have not yet reached a consensus about what is happening in the ground.



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