Was the earth born dry or wet?

A question that baffled scientists for a long period of time, and because our planet has been relatively close to the scorching heat of the sun 4.5 billion years ago, the belief remained that the Earth was born dry, and that it later got its water, which constitutes 70% of its area, from the collision of asteroids and comets from the depths Cold and icy of the outer solar system.

However, in a new study published in the journal Science on August 28, 2020. A French research team reported that they have identified space rocks as the source of this water, and that our planet has been wet since its formation.

Hydrogen-laden rocks

Researchers from the University of Lorraine's Petrographic and Geochemical Research Center (CRPG, CNRS) (Center de Recherches Petrographiques et Geochimiques) analyzed 13 different enstatite chondrites, a class known to resemble space rocks that merged to form Earth more than 4.5 billion years ago.

The researchers found, that this type of rock contains a lot of hydrogen, which is an indication that our planet was not born dry, as the team's calculations indicate that the rocks that formed the Earth were home to at least 3 times the amount of water held by the current oceans of the planet.

"Our discovery shows that the building blocks of the Earth may have contributed significantly to the Earth's water," said study author Laureate Bayani. "Hydrogen-bearing materials were present in the inner solar system at the time of the formation of the rocky planet, although the temperatures were too high to be possible." Water that condenses. "

Ann Bessler, a researcher at NASA's Johnson Space Center in Houston, commented in a companion article in the same issue of Science, saying, "Maybe Earth's water simply came from nebulous matter." From which the planet originated. "

A piece of meteorite (Sahara-97096), one of the chondrite instate studied, water concentrations in it were measured at about 0.5% by mass (uric alart)

Prevailing theory

Bayani says the results contradict the prevailing theory that water was initially brought to dry Earth by comets or far-reaching asteroids.

And that according to the first models of how the solar system appeared, the large disks of gas and dust revolving around the sun and forming the inner planets were extremely hot, and this would explain the arid conditions on Mercury, Venus and Mars;

But our blue planet, with its vast oceans and wet faces, is not.

So the scientists assumed that water came after the formation of the earth, and the main source - according to the scientists - was meteorites known as carbon chondrites rich in water minerals.

The problem, however, was that its chemical composition did not closely match that of our planet's rocks.

This is the opposite of a group of meteorites, "the chondrite anastatite" (EC), which has a chemical match much closer to Earth's rocks and contains similar isotopes of oxygen, titanium and calcium, indicating that they were the building blocks of Earth and other inner planets.

The results show that early Earth's rocks may have contained enough water to provide at least 3 times the amount of water in the oceans (Bixby)

Amazing results

To test whether the chondrita anestatite rocks are as dry as they were thought due to their formation near the sun or the source of the rich water on Earth, Bianni and her colleagues used a technique called "mass spectrometry" to measure the hydrogen content of the anastatite chondrite.

The team found that the rocks contain enough hydrogen to supply Earth with three times the mass of water in its oceans, and possibly much more.

They also found that the isotopic composition of anestate chondritic hydrogen is similar to that found in water stored in the Earth's mantle.

The isotopic composition of ocean water also corresponds to a mixture containing 95% of the water from anastatic chondrites and only 5% of the water transported by comets or asteroids rich in water.

Bayani says that the research also does not exclude that there are other sources of water on Earth such as comets;

But he points out that instate chondrites made a significant contribution to Earth's water budget at the time it was formed.