The interior of the earth can be roughly divided into three concentric layers with different compositions and properties: the core, the mantle, and the crust. The core of the earth is the core part of the earth. It is mainly composed of iron and nickel. The temperature is very high. The core of the earth cannot be observed directly, and researchers mainly observe it through seismic waves. Using data from a series of experiments from 1969 to 1974 at the U.S. Air Force’s Large Aperture Seismic Array (LASA) in Montana, researchers discovered the rotational speed of the Earth’s inner core, according to a study published in the journal Science Advances. About 0.1 degrees per year. Using a novel beamforming technique developed by University of Southern California professor John Vidale, the study analyzed beams produced by the Soviet Union’s 1971-1974 underground nuclear bomb tests on Novaya Zemlya in the Arctic, and on Amchitka Island in 1969. Data from two underground nuclear bomb tests of the “Milrow” and the “Cannikin” in 1971. By measuring the longitudinal waves produced by a nuclear explosion, they found that the rotation direction of the Earth’s core changed once in six years.
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