Almost all stocks of organics, nitrogen, water and other “bricks of life” were brought to Earth not by asteroids or comets, but by Theaia, the ancestor of the Moon. This is stated by geologists, who published an article in the journal Science Advances.
“The isotopic composition of the rocks, the fraction of sulfur, carbon and nitrogen and their total amount in the crust and mantle suggest that they had to get to Earth at a time when it was faced by a progenitor of the Moon the size of Mars. All the other scenarios can not explain the mass of these substances, nor the time of their appearance, “- said Damanveer Grewal (Damanveer Grewal) from the University of Rice in Houston (USA).
The Earth and other planets of the Solar System were formed inside a gas dust nebula surrounding the newborn Sun for several hundred million years of its life.
Originally, our world was a hot ball, the surface of which simply could not exist volatile elements and substances, including water, carbon and nitrogen compounds, as well as organic “bricks of life”.
The question then arises why all these substances are found on the surface of the Earth and in the Earth’s crust in great abundance. Scientists have several theories on this subject. For example, the presence of water is explained by the fact that it could have been “brought” to our planet by asteroids and comets that bombed the Earth’s surface about 3.8 billion years ago.
Recently, as Greval notes, scientists have begun to doubt these theories. The fact is that the ratio of carbon to nitrogen in the Earth’s rocks and asteroids-chondrites, presumably “suppliers” of water and organics, turned out to be very different. The first element on Earth is about twice as large as the wreckage of the former solar system “building blocks”.
American geologists have found an extremely unexpected explanation for this anomaly, studying how the chemical composition of the Earth’s core could affect how various elements, including carbon and nitrogen, were distributed over its mantle and crust.
The fact is that scientists have long suspected that the iron core of our planet can contain large amounts of sulfur. It, in turn, can make it less prone to absorbing carbon, nitrogen, oxygen and other volatile elements, of which the bark and mantle contain too much compared to chondrites.
Guided by this idea, Greval and his colleagues conducted a series of experiments with the analogues of core matter in their laboratory, compressing, heating and changing the proportion of sulfur in them. These data were used by scientists to create a computer model of the young Earth and to calculate different scenarios of its formation.
As these experiments and calculations have shown, the appearance of sulfur in the core affected the behavior of other “bricks of life” in a different way – it “pushed” carbon from the metal core into the silicate mantle, but with almost no effect on the behavior of nitrogen. This, as noted by researchers, well explains the current composition of the earth’s rocks.
Where could sulfur come from in the core of the Earth? According to the authors of the article, only one object can claim the role of its “carrier” – Teia, a protoplanet the size of Mars. She faced our world about 4.5 billion years ago, and as a result, her sulphur-rich nucleus drowned and “dissolved” in the Earth’s core, and the remains thrown into space became the Moon.
The same collision, as the American geologists’ calculations show, was supposed to bring to Earth almost all of its water, organic and other volatile substances needed for the birth of life.
Their mass, as scientists emphasize, exactly corresponds to the expected weight of Teija. This “coincidence” speaks in favor of their theory, and explains why the rocks of the modern Moon, as recently analyzed by the Apollo samples, contain an unusually large amount of water.