Thursday, July 21, 2016

The unusual structure of the Sea of ​​Rains was not formed by an asteroid – BBC

Region called Imbrium Sculpture, surrounding one of the lunar maria, consists of grooves and grooves extending 1,250 km along the entire circumference of the crater. Some of these grooves, say scientists, were formed fragments of the object that created the crater, not a substance in the territory after the impact. With the help of digital simulations and laboratory researchers were able to calculate the size of the impact of the object – almost half of the diameter of the asteroid Vesta. The text of the study can be available publication in Nature

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The dimensions of the proposed planetesimals, dented on the surface of the moon, can talk about its belonging to the asteroid belt, the objects of which participated in the bombardment of the planets and formed the left region of the moon. Late heavy bombardment, according to numerous assumptions, occurred between 4.1 billion and 3.7 billion years ago.

It is believed that during this process many craters on the moon were formed .

Later, due to the impact formed numerous elongated craters, ditches and furrows, which now we can observe in the northwest of the visible side of the Moon. Initially it was believed that the whole structure encircling one of the lunar maria, was formed as a result of one of the giant oblique stroke (about 30 degrees).

In order to determine the size of the impact of the object that created the sea structure Rains during simulation scientists took positioned perpendicular line crossing the large round pool and surrounding formation, a path to the additional distance from the center of the pool. With the intersection of these lines with circular formations on the surface, determine their trajectory, the researchers created a histogram. These areas, which never crossed the path of the original sea Imbrium basin evolved from fragments from the object side shock, which soon broke away from it. In this part of the impact of an asteroid, survived the impact, help to explain the traces which are inside the pool.

The following simulation experiments have shown that fragments of percussion objects have walked on the surface of the satellite before the soil on the surface of the forming structure, and to release lava surface. Moreover, their trajectories can be tracked in the area of ​​first contact with the impact object, along with some lines. These lines, as the analysis shows, the impact reaches the edges of the field.

is also one of the done research clearly corresponds to the position indicated by trenching, arranged around the Moscow Sea.

Thus, the simulations show that many objects surrounding the Sea of ​​Rains, have luchevidnoy form on this pool that speaks to their endogenous or structural origin

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According to their paper, the authors study, Peter Schultz and David Crawford, as a result of asteroid impacts during the bombing of change on the surface took place in several stages. Primarily due to the high temperature of the attacks took place flooded with lava, and the edge of the crater formed at the same time higher than its center. Rock fragments ejected at very high speeds close to the speed with which the impact occurs. The separated part of the impact of an asteroid due to irregularities on the surface spread further around the circle. In the end, during the late stage of the formation of the crater rocks formed by shock dilution is the free surface, took a luchevidny appearance in relation to the center.

This theory suggests that fragments have been in place long before the circle of the crater stage of formation of lava rocks.

The study also found that the size of the drum object created by the sea Schrödinger, Moscow and the East Sea, were about 45, 100 and 110 km, respectively.

These factors, and data on other percussion fragments that formed pools, suggest that in the asteroid belt, where they came from, these drums facilities, there are much more elements to the depletion zone, caused by the orbital migration of Jupiter and Saturn

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In addition, laboratory experiments that reproduce the impact, showed that numerous fragments (greater than 2% the original diameter) from each oblique impact that generated the pools should have to go through the planetary collision and to participate in the late heavy bombardment.

Thus, as a result of research, scientists have concluded that the impact object once belonged to the group protoplanets asteroid belt and its size is about half the diameter of the asteroid Vesta, namely 247 km in diameter.

in addition, the scientists say, that many huge fragments of the object was able to avoid collisions, forming large swimming pools.

The same could and “inner” planets – Mercury, Venus, Earth and Mars, which are so called because their orbits, closely located to the sun. Based on the size of the object, faced with the surface of the moon, the researchers believe that a substance formed as a result of shock and covered the moon and other planets during the late heavy bombardment, was in greater quantities than previously thought.

Mare Imbrium is one of the largest of the lunar maria, formed during the late heavy bombardment. Scientists estimate that, taking into account the diameter of the free-fall acceleration shock of the object that created the Sea of ​​Rains, was about 2.5 × 1022 (taking into account the volume of the asteroid’s density, constituting 2,5 g cc-1). Consequently, the total mass passing through alone the moon during the late heavy bombardment, was much greater than previously supposed 1021 g.

However, the impact of objects created by Sea of ​​Rains, was just one of many protoplanets, came as scientists assume with asteroid belt type E, which has been destabilized because of the great planetary migration.

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