An international group of scientists explained the deep differences in the composition of the Earth and Mars by the fact that the Red Planet was formed not where it is now, but much further – in the Main Asteroid Belt. Only then did it migrate into the interior of the solar system, which explains the strangeness in its composition. The corresponding article is published in Earth and Planetary Science Letters.
After the landing of earthly vehicles on Mars and the discovery of meteorites of Martian origin on Earth, the question arose as to why the Red Planet is so different in composition from ours. For example, silicates found on it in density are much inferior to terrestrial ones. At the same time, the composition of the solid planets that formed so close to each other as Mars and the Earth in theory should be very close.
The authors of the new work tried to simulate the process of formation of both planets in the framework of the Great Maneuvering hypothesis. This is the dominant explanation for the basic oddities of the solar system today-for example, the mass of Venus and Earth is many times larger than Mars. According to this hypothesis, Jupiter and Saturn in the course of gravitational interaction with each other and with the Sun first migrated closer to the light – up to the orbit of today’s Mars – and then returned back. Along the way, they, like a “vacuum cleaner”, cleared the area of the Main Asteroid Belt from protoplanetary small bodies, why there were no new planets. Along the way, Mars’s orbit was also partially “cleansed,” making its mass nine times smaller than the Earth’s.
However, in a few percent of the cases in the modeling of the researchers it turned out that Mars was formed not in the place where it is now, but 1.5 times farther from the Sun – in the Main Asteroid Belt. In this case, it really should have a lower density. Due to the “gravitational vacuum cleaner”, in the form of migrating through the belt of Jupiter, the heaviest and densest protoplanetary bodies were captured from there. Therefore, the youngest Mars only got the lightest silicates.
Then, due to gravitational instability from the passage of large planets, Mars migrated closer to the Sun. This can also explain why the early Mars was warmer than today and it had more water. The asteroid belt is farther from the Sun, and the water ice from there is weaker evaporated by the sun’s rays. Therefore, at first the young planet had more water and light gases. Only then did it lose their main part under the action of the solar wind in the absence of its own protective magnetic field.