Scientists have discovered another body in the solid core of the Earth
This work by Australian researchers may force school textbooks to be rewritten. Scientists say that in the solid core of the Earth, whose radius is about 1200 km, there is another body with a radius of about 650 km. They came to this conclusion by studying how seismic waves generated by earthquakes are reflected from the earth's core.
Recall that the inner solid core of the planet was discovered by the Danish seismologist Inge Lehmann in 1936. It “floats” in the center of the outer liquid core and consists of an alloy of iron and nickel, as well as lighter elements. It is the inner core that participates in the planetary geodynamo; the behavior of the Earth’s magnetic field and its magnetic poles depends on it.
The fact that there could be another metal sphere in the solid core was first discussed by scientists about 20 years ago. This was indicated by some oddities in the pattern of reflected seismic waves. However, at that time it was difficult to confirm this hypothesis due to the lack of global seismic stations. Now, thanks to a more sophisticated and widely deployed monitoring network, researchers are providing new evidence for this hypothesis.
Using the “echo” of seismic waves reflected from the nucleus, Australian scientists have discovered an unusual fact. The so-called P-waves, traveling at an angle of 50° to the Earth’s axis of rotation, turned out to be 4 slower than similar waves at other angles. That is, they are reflected weaker than the rest. The reason, according to scientists, is that in the center of the solid core there is a second with a radius of 650 kilometers.