The internal nucleus of the earth is changing shape

The mysterious internal nucleus of the Earth is changing in shape

By Alexandra Witze & Nature Magazine

The internal nucleus of the earth is changing shape, scientists have found.

The discovery is resolved A controversy that has been in the heart of the planet for a long time ago – Which was thought for a long time that was solid and inflexible. But it also opens new questions about how changes in the nucleus could affect the length of our 24 -hour day, the magnetic field of the earth and more.

“After decades of research and debates, we are reaching a growing image of the changing internal nucleus,” says Xiaodong Song, a seismologist at Beijing University in Beijing, who did not participate in work.

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The researchers made the discovery analyzing how the seismic waves of the earthquakes traveled from the South Sandwiches Islands in the South Atlantic Ocean to the symmeters in Alaska and Canada, on the other side of the planet. The waveforms, or shapes, of some of the seismic signals changed between 2004 and 2008. Those changes occurred because the waves briefly penetrated the internal nucleus of the earth, which was changing shape, scientists say.

“For the first time we see that it is deforming,” says John Vidale, a seismologist at the University of Southern California in Los Angeles. He and his colleagues report the find today in Geoscience of nature.

A dynamic inner land

The internal nucleus of the Earth is surrounded by an outer nucleus, and the interface between the two, around 5,100 kilometers below the planet’s surface, is a mysterious kingdom. Previous seismic studies revealed that the internal nucleus is solid metal and rotates within a super hot external nucleus, also mainly made of metal, including iron and nickel. Researchers have tracked how this rotation accelerates and slows over time, and have discovered that it is rotating at a slightly different speed from the rest of the earth.

Some scientists have proposed that changes in the seismic signals that pass through the Earth are not caused by the rotational changes of the nucleus, but by the physical changes in the limit of the nucleus of the internal nucleus -subterrane. The new work suggests that both explanations are correct. Many changes in the waveforms of the earthquakes of the South Sandwiches islands can be attributed to the nucleus rotation, says Vidale. But others are probably caused by the deformation of the limit of the nucleus of the internal nucleus -underground through the development of bumps in some areas.

The study helps illuminate a dynamic internal land. The internal nucleus grows slowly over time, since the iron of the external nucleus crystallizes on it. This process drives in the external nucleus, which supports the magnetic field of the Earth. Changes in internal nucleus rotation can also affect the length of our day.

“Ideally, we would like to unite all these things we are seeing together” to make Deep Earth less mysterious, says Vidale.

This article reproduces with permission and it was First published February 10, 2025.