Instead of a single catastrophic strike, the Moon could have been formed from many massive impacts, creating a collection of small moons that merged into one.
More than 4 billion years ago, when the Earth was still a massive asteroid disorder, it was believed that another planetary body the size of Mars (hypothetical world - Theia) crashed into our children's planet, causing subsequent development. Because of this collision, molten rock erupted from the rubbish of two objects and hardened into the shape of the moon, which we know today. But is there an alternative scenario that does not require a catastrophic effect?
During the formative years of the Solar System, massive blows were common, and planetary bodies gravitationally pushed each other’s orbits. In the end, everything was relatively stabilized, and the planets settled on the orbits that we are seeing today. Many moons formed around this time. Some came from the planets, others were asteroids (or exiled from other planets) trapped by gravity. In the case of the Earth, which was rapidly gaining mass from countless asteroids, massive blows became a natural state.
The study, published Monday in the journal Nature Geoscience, states that these multiple hits may have created many satellites, united to create a Moon. In this case, the influence of Theia is not required. “Our model assumes that the ancient Earth created a series of moons, each of which was formed from collisions with the proto-Earth,” said Hagai Peretz from Technion (Israel Institute of Technology). - “It is likely that they collided with the Earth or with each other and formed larger satellites”.
This suggests that in the process of the formation of our planet, it experienced many massive blows, each of which threw debris into an orbit connected by mutual gravity, forming mini-moons. Having formed, they took their place in orbit. But the new satellites influenced the older ones, which caused some destabilization. Because of this, some mini-moons detached from orbit, while others fell to the surface of the planet. The rest merged, creating a growing object - the modern moon.
“It is likely that small satellites could cross orbits, collide and unite,” said Raluca Rufu of the Weizman Institute in Israel.
This chain of effects is consistent with the formation model of the early Earth and does not suggest that there was only one catastrophic impact. “A long series of such contacts“ moon-moon ”gradually formed one large object,” Peretz added.
This is a hot topic in the astrogeological community. However, many secrets remain, and this model will be considered as a convincing alternative idea.