The heart of the Earth, the inner core, may be smaller than expected and rich in iron, with a radius of just 650 kilometers. The study published in the journal Nature Communications and carried out by Thanh-Son Pham and Hrvoje Tkalčić, both of the Australian National University in Canberra, indicates that a small ‘inner core’ exists within the Earth’s core.
What is inside the planet is still shrouded in many shadows today, in fact there is no technology capable of penetrating the depths of the Earth and directly showing its structure or composition. The only concrete tool available are the seismic waves which, crossing the entire planet, are reflected and refracted thus providing, like the acoustic waves used in an ultrasound, information on how the Earth is structured. Thanks to these analyses, it was possible to understand that the planet is composed of a series of concentric layers that are distinct from each other: crust, mantle, outer core and inner core.
By now analyzing a huge amount of data relating to the propagation of seismic waves detected by increasingly large and sensitive detection networks installed in recent years, the Australian researchers have dusted off an old idea first proposed about twenty years ago. The idea is that the planet’s inner core is in turn made up of two layers: an external one that is not very homogeneous and a very compact inner one with a radius of just 650 kilometers. Supporting this thesis is the sensitivity achieved by the most recent seismographs: the traces of this ‘internal core’ are in fact almost imperceptible and recognizable only thanks to the sensitivity of new technologies. The presence of a possible stratification of the inner core, the researchers explain, could indicate that the history of our planet has been even more complex than expected.
Source: Ansa
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