Research has not yet taken into account hydrogen at the core of the Earth.
It is one of the greatest mysteries of our secular house. Where did the water come out on Earth?
The answer to this question has a wider, in fact, secular meaning. It shows if water is also common to the stone exoplanets of the distant universe.
A new study by Arizona State University scientists argues that Earth's water comes not only from asteroids but also directly from the plant nebula in the solar system. This means that water can also be abundant in the exoplanets that have never suffered from asteroids bombardments.
Research paper published by the Journal of Geophysical Research: Planets.
Many researchers believed that water was falling from the sky. On Earth it was as part of the asteroids. For example, asteroids can contain more than 20% water.
One such scenario suggested the isotopic composition of the oceans. In particular, the ratio of heavy deuterium hydrogen (still contains a hydrogen) to a slight hydrogen process.
"It's like a blind spot of a professional community," says co-author Steven Desch. "Scientists measured the proportion of isotopes in the ocean and found that it corresponded to the proportion of asteroids, so they believed that all the water came from asteroids."
Surprises from the depth
However, recent research has found that the isotopic composition of ocean water is not representative. Hydrogen samples from the debris, particularly from the core region and the earth's shell, contain much less hydrogen.
Rare sulfur and neon gases with an isotopic composition of stunning origin were found in the same area. They seem to come straight from the vegetable nebulizer that creates the sun.
The deep creatures of the planet brought us another important finding. Although the core of the earth is mainly iron and nickel, about 7% of its weight corresponds to light elements.
Among others, hydrogen. At the time of the formation of the Earth, it had to be ironed, and with it it fell to the center of the planet.
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Water on Earth seems to have a dual origin.
Although hydrogen is only a fraction of the mass of the Earth's core, the whole is obviously enormous.
"Geochemical evidence indicates that the Earth's core contains a quantity of hydrogen that corresponds to several oceans, and may even contain most of the Earth's hydrogen," the researchers said in a study.
Scientists add that research has not yet taken into account how the iron binding process has affected the isotopic composition of the residue that remained near the surface.
"When the hydrogen molecule collapses, the more easily isotope bound to metals, so the isotopic composition of the environment is changing," the investigators explain.
At least one hundred molecules
Scientists from the Arizona State University have taken this influence into account in their calculations. They found the initial isotopic composition of Earth's hydrogen, which revealed what resources and how much they contributed to it.
The results of the study show that part of the terrestrial hydrogen – and therefore water – does not come from asteroids, but directly from the plant nebula in the solar system.
"For each molecule of terrestrial water, one or two come from the sun's nebula," says lead author Jun Wu.
"Charging" of hydrogen
The Earth has acquired sunflower hydrogen at a very early stage of development. At a time when violent clashes with the fetuses of other planets melted in part to create hundreds of miles of deep magma oceans.
At this time, gases from the sunny nebula were gravitationally packed. Except sun and neon and hydrogen.
The nebula contained less hydrogen than the asteroids. But in contact with the magmatic ocean, light iron was connected with iron clumps. The heavy deuterium remained near the surface.
The iron eventually fell into the melt in the center of the body and formed (mainly) the metal core. Together with the absorbed hydrogen, whose isotope ratio differed from the later oceans to the surface.
Good news for life
Researchers from the Arizona State University recall that planets in other planetary systems may not have sufficient supply of asteroid-rich water.
But the findings of their study show that water from such a world will not be lost. An insignificant amount of feedstock – hydrogen – is taken directly from the plant nebula.
"From our model, it seems that the emergence of water will necessarily arise on every planet of the exoplanet," says Jun Wu. "The emergence of water is an inevitable consequence of the formation of quite large planetary planets outside the solar system."