# LuV The/Chapter IV
## REVERENCE FOR MARS

If we admit that the Moon was formed in the Main belt but deliberately began to elude co-orbital drifting with other planetesimals, than we should trace its possible walk line. An inward migration scenario means that it should somehow intersect the path of Mars.
Let's take a view on this terrestrial planet. We know that it is approximately half the diameter of Earth, it's heliocentric period is slightly less than our 2 years and the distance from the Sun is 1.5 times farther than that of Earth.
Near the equator we can find a huge canyon called Valles Marineris. To the west from it lay the Tharsis region with high ancient volcanoes. Westmost, at the edge of this plateau elevates Olympus Mons – the tallest planetary mountain in the Solar System.
Probably the most outstanding geological feature on Mars is a sharp contrast in elevation between the Southern and the Northern hemispheres. We know from Wikipedia, that average thickness of the Martian crust in the North is 32 km, and in the South it is 58 km. In other words, two-thirds of the Martian surface are the southern highlands, and the rest one-third belongs to relatively flat North Polar Basin.
There are several theories on how the North Polar Basin was created. One of them states that a single mega-impact with a planetary-sized body occurred more than 4 billion years ago. If confirmed, it would be the largest impact basin yet discovered.
This enormous basin has an elliptical shape and spans 10,600 by 8,500 km, or roughly 4 times the size of the Moon's largest crater. We remember that there was a conjecture about possible elliptical structure of the South Pole–Aitken basin. Is this a coincidence?
Earlier we proposed a theory that the lunar basin was formed by a vertical impact, but this collision was softened by icy crust of the body. Probably there is possibility of forming slightly ovate crater even during a vertical impact, if we suppose that bodies had a little moment of sliding when ice began to melt.
Yes, we think that the second body of this cosmic collision was Mars itself. During inward migration the Moon slammed into the Red Planet, and that led to formation of the biggest basins on both astronomical bodies. (But this scenario imply that the present poles of them were not poles before interaction.)
If the Moon really impacted Mars more than 4 billion years ago, some Martian cataclysms would be easier to explain:
* Mega-impact could slightly displace the orbit of Mars comparatively to its center. We know that Mars' eccentricity is greater than that of every other bigger planet. But it seems to be circular enough with only a shifted center. So probably difference between the aphelion and perihelion was minimal before the impact event.
* Huge magmatic waves should have appeared after such collision. Apparently they could be the reason why volcanic activity started on Mars. Since that very hot material waves couldn't pass through all circle of mantle layer, they had to break through in areas near the equator.
* Countless shatters and chips of the icy crust should have fallen on Martian surface within this scenario. They could form relatively sustainable hydrosphere on the Red Planet.
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