The moon was formed by the collision of the Earth with the planet Theia. Scientists have found further evidence of this hypothesis.
According to this theory, the Moon formed about 4.5 billion years ago as a result of the collision of the Earth with a planet the size of Mars called Theia. The fragments of the Earth and Theia make up our satellite. The hypothesis appeared in the 1970s and remains the most popular in scientific circles to this day. Firstly, because of the similarity of the chemical composition of the Earth and the Moon, and secondly, because the Moon has practically no iron core.
In this case, however, our satellite should mainly consist of the matter of the planet Theia, but the composition of the Moon is more similar to that of the Earth. This could mean that Earth and Theia had a similar chemical composition. But previous studies have limited the possibility of this to only one percent. The new experiment showed different results.
Scientists' simulations have increased this probability to 20-40%. Why could Earth and Theia be so similar? The researchers explain this by the fact that the planets were "not far" from each other (therefore, they probably collided), in close parts of the protoplanetary disk, from which they once formed, at approximately the same distance from the Sun.
The hypothesis is also confirmed by the data of the measurements of the content of the isotope of tungsten-182, which occurs after the decay of hafnium-182, in the soils of the Moon and the Earth, carried out by the US astronauts during the Apollo mission. After all, then it turned out that on the surface of the Moon this isotope is more than on Earth (by 27 parts per million). This is due to the fact that the Earth intensively accumulated the matter of asteroids and comets.
The Earth and the Moon are not twins, born from the same planet, but they are sisters in the sense that they grew up in the same environment.