The earth is unique in our solar system: it is the only Earth planet with a great deal of water and a relatively large moon that stabilizes the axis of the Earth. Both are essential for the development of life on Earth. Planetologists from the University of Münster (Germany) have already been able to show for the first time that the water has come to Earth with the formation of the Moon about 4.4 billion years ago.
The moon was formed when the Earth was hit by a Mars-sized body, also called Theia. Until now, scientists have assumed that Thea originates from the inner solar system near the Earth. However, researchers from Münster can now show that Thea comes from the external solar system and supplies large amounts of water to Earth. The results are published in the current issue Nature Astronomy,
From the outer to the inner solar system
Earth is formed in the "dry" internal solar system and therefore it is a bit surprising that there is water on Earth. To understand why this is so, we need to go back to the time when the solar system was formed about 4.5 billion years ago.
From earlier studies, we know that the solar system is structured so that "dry" materials are separated from "wet" materials: the so-called "carbon" meteorites, which are relatively rich in water, come from the external solar system. while the drier non-carbonate meteorites come from the inner solar system.
While previous studies have shown that carbon materials are probably responsible for the supply of water to Earth, it was not known when and how this carbon material – and thus water – came to Earth.
"We used molybdenum isotopes to answer this question. Molybdenum isotopes allow us to clearly distinguish between carbon and non-carbon material, and as such represent a "genetic footprint" of material from the outer and inner solar systems, "explains Dr. Gerrit Budd of the Institute of Planning in Münster and the lead researcher.
The measurements made by the Münster researchers show that the isotopic composition of molybdenum on Earth lies between those of carbon and non-carbon meteorites, indicating that part of the Earth's molybdenum originates from the external solar system. In this context, the chemical properties of molybdenum play a key role because, since it is an iron-loving element, most of the molybdenum on Earth is in the nucleus.
"The molybdenum, which is available today in the mantle of the Earth, therefore originates from the late stages of Earth formation, while the molybdenum from earlier phases is entirely in the nucleus," explains Dr. Christoph Burckhard, second author of the study.
The results of the scientists show for the first time that the carbon material from the external solar system arrived on Earth late.
But the scientists are taking another step further. They show that most of the molybdenum in the mantle of the Earth is delivered by the Theia protoplanet, whose clash with the Earth 4.4 billion years ago has led to the formation of the moon.
However, since much of the molybdenum in the mantle of the Earth originates from the external solar system, it means that Tea herself also originates from the external solar system. According to scientists, the collision has provided enough carbon material to take into account the total amount of water on the Earth.
"Our approach is unique because it first allows us to connect the origin of the water on Earth with the formation of the moon. In simple terms, without the Moon, there will probably be no life on Earth, "said Thorsten Klein, a professor of planetary science at the University of Münster.
Please donate today
Did you like this article? Then, please consider donating today to ensure that the Eurasia Review will continue to be able to provide such content.