Where does the Moon come from? From the earth. According to a new theory developed by researchers at Harvard University (USA),the Moon was part of the Earth itself until its mass was shot into space during the collision with another body. This would explain why our planet and its satellite have such a similar chemical composition, according to the authors in the journal.Science.
At the time the Moon was formed, the Earth was shaped like a spheroid and was spinning on itself much faster than it does today. So much so that the Earth day lasted around 2.3 hours. Circling at such a speed, it is foreseeable thatan impact against a body half the size of Marscause the excision of sufficient material to form another body with the same isotope composition (isotopic fingerprint), which had previously been shown to share both celestial bodies. In simulations, the study authors suggest that the body that caused the collision penetrated to the Earth’s core, temporarily forming a deep hole in our planet. The Earth, according to this new theory, reached its current spin speed (one turn every 24 hours) due to the gravitational interaction between its orbit around the Sun and the Moon’s orbit around Earth.
This scenarioagrees with the masses of the Earth and the Moon, the low iron content of the satellite and the coincidences in the chemical composition of the mantles of both objects. The investigators also assure that, if the events were as they describe, for a timethe Moon was 20 times bigger in the skyat its time of closest approach to Earth.
