A research conducted by a team from University of California, Los Angeles (UCLA) has confirmed that soil samples from the Earth and Moon have the same combination of oxygen isotopes, which implies that both worlds originate from a direct collision between ancient planetary bodies.
REMNANTS OF A LONG-GONE WORLD
It has been long thought that the Moon was born in a huge clash of planetary bodies in the ancient times of our Solar System. Familiar as the “Giant Impact Hypothesis” (or the “Big Splat”), it suggests that an embryonic planet had the bad luck to form in a Trojan orbit with Earth.
About 100 millennia after the Solar System was born, Earth and this intruder clashed, because it is impossible for two planets to be in the same orbit for very long time.
The result of this collision was the present Earth-Moon system.
There is a theory that Theia—a poetic name given to the long-gone world, taken from the Titaness of Greek mythology who gave birth to the Moon—just side-knocked our planet at a 45-degree angle, or bigger.
If this were true, it could be supposed that the Moon is consisted in major part from the crustal material of Theia, and the Earth and its satellite would not have same chemical signatures. A research in 2014 conducted by a German team presented this idea.
However the new study, conducted by a team from UCLA, has confirmed that the Earth-Theia collision was a direct one that resulted in the birth of two brand new, co-orbiting planets, the Earth and the Moon.
The proof appears in a shape of oxygen isotopes—which is atoms with varying quantities of neutrons—fossilized inside the crustal rocks of the Earth and its satellite. Most of the oxygen appears as O-16, regular oxygen atom with 8 protons and 8 neutrons; however small amounts of heavier isotopes, O-17 and O-18, compose an exceptional blend that characterizes the chemical signature of any planetary body.
Earth has a one of a kind pair of oxygen isotopes, as well as Mars, Venus, Mercury, and so forth.
The team examined seven Moon rocks and six earth volcanic rocks.
It was established that there is no difference between the Earth’s and the moon’s oxygen isotopes.
WHERE DID ALL THE WATER GO?
It is clear is that the material of Theia is equally dispersed through both the Earth and Moon, implying that whatever preceded was destroyed and re-composed into something new.
In fact it is not an impact between Theia and the “Earth,” but a clash between Theia and some other, obscure and anonymous planet that used to be in the same orbit. The two planets were devastated, and—just like the phoenix—were once again reborn as the present Earth and Moon.
But then there is the matter with Earth’s water. The clash must have vaporized the water on both planets; maybe, following impacts with H2O-bearing asteroids and comets brought the Earth’s future water.
The Solar System was still forming.