Deep in the depths of the earth, her core surrounds a couple of mysterious structures, as if gigantic headphones. Lifting through the bottom robe to a height of up to 1000 kilometers, they resemble clusters of huge bubbles. It was possible to detect them due to the slowdown in these "bubbles" of seismic S-waves, which is associated with relatively high density, so formally they are called "large areas with low shift speed" (LOW-SHEAR-VELOCITY PROVINCES, LLSVP). One of them runs under Africa, the other is under the Pacific Ocean.
These dense "bubbles" are the largest structures of the earthly mantle, which take up to six percent of the entire volume of the planet. However, that they represent themselves when it is and how they appeared until it is known. There are only a number of hypotheses - for example, about crystallization in the primary magmatic ocean of the Earth. Another version associates LLSVP with the most ambitious blow, which 4.5 billion years ago almost destroyed the planet, but in the end he led to the appearance of her moon.
Such a hypothesis was considered by geologists from the University of Arizona, who spent with her on the 52nd lunar and planetary conference. In fact, some evidence suggests that "bubbles" existed at least immediately after the collision.
It is believed that the Heavenly Body Body - Tayya faced with the Earth - was about three times less than her, approximately with modern Mars. Although a geologist from the University of Arizona Steven Desch (Steven Desch) believes that Tayya was much more. The fact is that part of its material entered the moon. Analysis of lunar samples shows that the ratio of hydrogen isotopes - duration to deuterium - in them higher than on Earth. To keep the excess of the lightest atoms, it turns out a walk, Tayya must be a massive and dense body.
The modeling conducted by Arizonian geologists showed that as a result of the impact, its kernel merged with the earth, and in the outer surface of the formed nucleus could be preserved separate clots of the Tayya dense mantle (1.5-3.5 percent denser than the earth). Thus, most of the dead planet may be hiding in LLSVP: according to scientists' estimates, the total mass of the "bubbles" of the guise of the larger mass of the moon. However, while this model remains only early hypothesis, speculation, and it is required to develop and clarify before we find out the true picture.
Source: Naked Science