An international team of scientists was able to figure out the reasons for the deep differences in the composition of the Earth and Mars. The fact is that the Red Planet was not always where it is now, but much farther from our planet - in the Main Asteroid Belt. After its formation, it moved deeper into the solar system. This is what explains the strangeness in its composition. Scientists shared their research and findings in an article published in the scientific journal Earth and Planetary Science Letters.
After numerous analyzes of the Martian soil by the spacecraft landed on the Red Planet, as well as the detection and study of meteorites of Martian origin on Earth, scientists have questions as to why Mars is so different in composition from our planet. For example, Martian silicates are significantly inferior in density to their terrestrial counterparts. If the planets formed next to each other, then, in theory, their composition should be very close? The remark is correct, but in practice it turns out to be a completely different picture.
To solve this puzzle, the researchers simulated the formation processes of both planets according to the Great Maneuvering hypothesis. It offers the most compelling explanation for the oddities in the solar system to date. For example, why the mass of Venus and Earth is many times greater than Mars. According to the hypothesis, the gas giants Jupiter and Saturn, in the course of gravitational interaction with each other and with the Sun, first moved closer to our star (up to the present orbit of Mars), and then returned back to their places. As a result, they, like a vacuum cleaner, cleaned the area of the Main Asteroid Belt from protoplanetary bodies with their gravitational forces, effectively depriving them of the possibility of forming new planets there. As part of this process, the gas giants also partially captured the vicinity of the original Martian orbit by their gravitational influence, which ultimately led to the fact that the mass of the Red Planet is now nine times less than Earth's.
In some cases, modeling showed that Mars could have formed not where it is now, but about 1.5 times farther from the Sun - that is, somewhere in the main asteroid belt. In this case, its lower density, in comparison with the earth's, would be explained. Due to the "gravitational tractor" in the form of moving through the Jupiter belt, the densest and heaviest protoplanetary bodies were pulled into the inner boundaries of the system from there. As a result, only a part of the forming matter in the form of the lightest silicates got to the share of the still young Red Planet.
Due to the gravitational instability in the region, from the constant walking back and forth of the large planets, Mars eventually moved closer to the Sun. This, incidentally, may explain why young Mars was warmer than the current one, as well as why it could have more water than now. As you know, the asteroid belt is located farther from the Sun, therefore, water ice in this region evaporates under the influence of sunlight much more slowly. Initially, the planet had more water, and the atmosphere contained more gases. Mars lost the main part of its water reserves and gases after it moved closer to the Sun. A powerful solar wind and the planet's absence of its own protective magnetic field played an important role in this.
Nikolay Khizhnyak