As we know, water covers 70% of the earth’s surface and is vital to life, but how water gets here has been a long-term scientific debate.
Laurette Piani, the cosmic chemist who led the research, told AFP that this discovery contradicts the popular theory that water was brought into the initially dry by a far-reaching comet or asteroid. The Earth’s.
According to early models of how the solar system formed, the massive disks of gas and dust that revolve around the sun and eventually form inner planets are too hot to sustain ice.
This can explain the barrenness of Mercury, Venus, and Mars, but it cannot explain our blue planet, because it has a vast ocean, a humid atmosphere and abundant geological conditions.
Therefore, scientists believe that water comes with water, and the main suspect is meteorites, called carbonaceous chondrites, which are rich in hydrated minerals.
But the problem is that their chemical composition does not match the rocks of our planet.
Carbonaceous chondrites also formed in the outer solar system, which made it unlikely to hit the early Earth.
Another group of meteorites, called encumbrite meteorites, are more chemically matched and contain similar oxygen, titanium and calcium isotopes (types).
This shows that they are the building blocks of the Earth and other inner planets.
However, because these rocks were formed close to the sun, they are considered too dry to explain the abundant reservoirs on earth.
To test whether this is true, Piani and her colleagues at the Recherches Petrographiques et Geochimiques Center (CRPG, CNRS/University of Lorraine) used a technique called mass spectrometry to measure the hydrogen in 13 types of enstatite meteorites. content.
These rocks are now very rare, accounting for only 2% of the known meteorites in the collection, and it is difficult to find uncontaminated primitive rocks.
The research team found that these rocks contain enough hydrogen to provide the earth with water at least three times the mass of its ocean water, and possibly more.
They also measured the two isotopes of hydrogen because their relative proportions are very different from one celestial body to another.
Piani said: “We found that the hydrogen isotopic composition of enstatite chondrites is similar to that of water stored in the mantle.”
Studies have found that the isotopic composition of the ocean is consistent with a mixture of water containing 95% of the gabbro meteorite, which further proves that these isotopes constitute most of the earth’s water.
The author further discovered that the nitrogen isotopes in the encumbrite meteorites are similar to those of the earth, and proposed that these rocks may also be the source of the most abundant components in our atmosphere.
Piani added that the study did not rule out that comet meteorites made a significant contribution to the Earth’s water budget when they formed.
NASA planetary scientist Anne Peslier (Anne Peslier) wrote in the accompanying editorial that the work “brought a vital element of elegance to this puzzle.”
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