American geologists say that the Earth’s inner core could not have developed 4.2 billion years of the Earth in the form in which scientists imagine it today, since this is not possible from the point of view of physics, according to an article published in the journal EPS Letters.
“If the nucleus of the young Earth consisted entirely of a pure, homogeneous liquid, then the inner nucleolus should not exist in principle, since this matter could not cool down to the temperatures at which its formation was possible. Accordingly, in this case the nucleus may be inhomogeneous on composition, and the question arises as to how it became so, this is the paradox we discovered, “says James Van Orman of the Case Western Reserve University in Cleveland, USA.
In the distant past, the core of the Earth was completely liquid, and not consisted of two or three, as some geologists now suppose, of layers – an inner metal core and the surrounding melt of iron and lighter elements.
In this state, the nucleus quickly cooled and lost energy, which led to a weakening of the magnetic field produced by it. After some time this process reached a certain critical point, and the central part of the nucleus “froze,” turning into a solid metallic nucleolus, which was accompanied by a surge and growth in the strength of the magnetic field.
The time of this transition is extremely important for geologists, as it allows us to estimate approximately at what speed the core of the Earth is cooling today and how long the magnetic “shield” of our planet will last, protecting us from the action of cosmic rays, and the earth’s atmosphere from the solar wind.
Now, as Van Orman notes, most scientists believe that this happened in the first moments of the life of the Earth thanks to a phenomenon, an analog of which can be found in the atmosphere of the planet or in soda filling machines in fast food restaurants.
Physicists have long ago discovered that some liquids, including water, remain liquid at temperatures considerably lower than the freezing point, if there are no impurities inside, microscopic ice crystals or powerful oscillations. If it is easily shaken or put a speck of dust into it, then such a liquid almost instantly freezes.
Something similar, according to geologists, occurred about 4.2 billion years ago inside the core of the Earth, when part of it suddenly crystallized. Van Orman and his colleagues tried to reproduce this process using computer models of the planet’s interior.
These calculations have unexpectedly shown that the inner core of the Earth should not exist. It turned out that the process of crystallization of its rocks is very different from how water behaves and other super-cooled liquids – this requires a huge temperature difference, more than a thousand degrees Kelvin, and the impressive size of a “speck of dust,” whose diameter should be about 20-45 kilometers.
As a result, the two scenarios are most likely – or the core of the planet should freeze completely, or it should still have been completely liquid. Both are not true, since the Earth does have an internal solid and external liquid core.
In other words, scientists have no answer to this question. Van Orman and his colleagues suggest to all geologists of the Earth to think how a large enough “piece” of iron could form in the mantle of the planet and “drown” in its core, or find some other mechanism that would explain how it was divided into two parts.