We're still not entirely sure how Mars formed: there are many questions about its amazing geology and its strange (but attractive) potato-shaped moons, which is unusual. But now, a study published in Geophysical Research Letters may have solved some of the Red Planet's old mysteries.
The hemispheres of Mars are geologically different from each other (smooth relief in the north, mountains and craters in the south) and the planet itself has a surface composition that is different from that of the earth. Moreover, the aforementioned potato moons serve as an additional addition to its mysteries. Researchers Stephen Moisis and Ramon Brasser have suggested that there can be only one explanation for all three phenomena: a giant asteroid collision.
After the first planets were formed, many space debris remained in the form of asteroids of various sizes in the early solar system. These asteroids crashed into the planets, with their bombardment they changed the relief (just remember our Moon) and the composition of the planet's surface, adding their own chemical elements to it. The giant impact model suggests that rocky inner planets of roughly the same chemical composition were originally smaller than they are today. Falls of asteroids increased their masses, as they absorbed the elements of this space debris, then they themselves changed.
The researchers carefully studied the Martian meteorites and realized that such a composition of metals in its mantle could have arisen after one, but large interaction with the asteroid. They calculated the size of an asteroid needed to deliver these metals, taking into account data on Mars, and got the final result: an asteroid the size of Ceres, about 1200 km wide, could have affected the planet about 4.43 billion years ago. After that, Mars was probably also hit by other asteroids, but with lesser consequences.
The asteroid likely ended up in the northern hemisphere of Mars, which would explain the fact that the planet's crust there is younger than that of other Martian regions. In this case, enough material was ejected from the surface to create a planetary ring. Perhaps this could later lead to the formation of two moons of Mars - Phobos and Deimos. This would also explain their composition: all three bodies are composed of Martian and non-Martian elements.
In cosmological science, we still do not know anything for sure, but the fact that this theory solves several mysteries of the origin and geological features of Mars and its satellites gives it weight.
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