Before the appearance of the moon, our planet had to experience many catastrophes that led to the emergence of unstable and short-lived satellites.
Of all the versions of the origin of the Moon, the impact hypothesis enjoys the greatest authority. According to her, the satellite was formed as a result of the collision of the young Earth with another protoplanet - from the mixed matter of both bodies, thrown into orbit. At the same time, it is unlikely that such a catastrophe was the only one: in that turbulent era, the Earth must have experienced such impacts many times. What happened to the "proto-satellites" that probably appeared as a result of this?
This issue is addressed in an article published by Israeli and European astronomers in the Monthly Notices of the Royal Astronomical Society. The authors modeled the impact formation of many "protosatellites" and their gravitational interactions with the planet and with each other. Calculations have shown that such chaotic interactions lead to their merging into larger bodies, and then either to their ejection outside the Earth's orbit, or to their final fall to the planet's surface.
Such a "moonfall" could be of great importance for the earth's geology and the entire further evolution of the planet. Of course, the direct traces of the collisions that took place in the Catarchee more than four billion years ago were long ago destroyed by multiple changes in the lithosphere. However, simulations of the collisions showed that they should have affected the planet's rotation rate. In addition, their traces can be found in the heterogeneity of the composition of the earth's crust: for example, small differences in the content of isotopes, which have been preserved until the present time.
Sergey Vasiliev