The first days of the Earth may have been quite different than previously imagined: new studies indicate that our planet may have appeared quite wet. Until today, the most accepted theory was that the blocks that built our home were dry, because they originated very close to the Sun. The water would only have arrived here after the impact of ice-filled comets and asteroids.
However, scientists at the Center for Petrographic and Geochemical Research at the University of Lorraine in Nancy, France, believe that water appeared on the planet with materials present in the Solar System itself and not through comets and asteroids coming from far more distant places. The research looked at 13 chondrite meteorites from enstatites, which are similar to the space rocks that formed Earth about 4.5 billion years ago.
“Our discovery shows that the Earth’s building blocks may have contributed significantly to the planet’s water,” says Laurette Piani, of the research center. “Hydrogen-containing materials were present in the Solar System at the time of the formation of the rocky planet, although the temperatures were too high for water to condense,” he adds.
For the researcher Lionel Vacher, from the University of Washington, in St. Louis, in the United States, the discovery is interesting because it shows that the chondrites of enstatites contain abundant amounts of water, contradicting the idea that they were practically dry. It is worth mentioning that this type of meteorite is quite rare, representing only 2% of the meteorites found to date.
However, these chondrites have isotopes of oxygen, titanium and calcium similar to those of Earth. The new research revealed that, in addition to these elements, enstatite chondrites also have hydrogen and nitrogen isotopes very similar to those found on our planet. Isotopes of space materials help to identify their origin.
“If enstatite chondrites are effectively the building blocks of our planet, as was strongly suggested by their isotope compositions, this research shows that they would have provided enough water to fill the Earth,” explains Vacher.
Scientists were careful to select the most primitive chondrites in existence, avoiding the risk of analyzing materials that could have been impacted by terrestrial water. For the analysis, the techniques of conventional mass spectrometry and secondary ionic mass spectrometry were used. The results were published in the journal Science last week.