The material originated from Earth and Mars
A more detailed comparison with the date of the isotope composition of Earth, Mars and some types of meteorites has now provided new insights into the formation of planets in the inner solar system: Mars and Earth formed mainly from matter from the inner sun. Not from the structure and beyond the orbit of Jupiter – as well as from “lost building materials”.
Mars meteorite Elephant Moraine (EETA) 79001. Scientists have studied these and other Martian meteorites in their study.
Image: NASA / JSC [Groansicht]
Earth and Mars are mostly made up of objects from the inner solar system; Only a small fraction of the “building materials” of these two planets form beyond Jupiter’s orbit. This is the result of a study by a team of researchers led by Westfilm Wilhelms-University (WWU) Mnster. In it they present a very detailed comparison with the isotopic composition of Earth, Mars and the date of the original building materials of the inner and outer solar system. Some of these materials are still found today mostly in unmixed meteorites. The results of the study have long-term effects on our perceptions of the formation process of the planets closest to the Sun, Mercury, Venus, Earth and Mars. This refutes the theory that the four rocky planets grew to their current size by accumulating only millimeters of dust from the outer solar system.
When our solar system was born about 4.6 billion years ago, a disk of dust and gases orbited the still younger Sun. Two theories explain how inner rocky planets evolved from this original building material over millions of years. According to the old theory, dust accumulated in larger and larger pieces, which gradually reached the size of our moon in the inner solar system. Mercury, Venus, Earth and Mars emerged from a combination of these precursors.
On the other hand, the most recent theory describes a different growth process: thus, millimeters of dust migrated from the outer solar system toward the sun. On their way, they met the forerunners of the inner solar system, where they anchored and, gradually, aided their present size. Both theories are based on model calculations and computer simulations that simulate the conditions and movements of the early solar system; Both describe the possible path for the formation of planets. But which is right? What process really happened?
To answer this question, Mnster’s researchers Cte d’Azur Observatory Nice, from California Institute of Technology In the United States, the Berlin Museum Fur Naderkunde and the Free University of Berlin saw the perfect combination of the rocky planets Earth and Mars. “We wanted to find out if the building material of Earth and Mars came from the outer or inner solar system,” he said. Christoph Burkhardt from Mnster. Isotopes of rare metals such as titanium, zirconium and molybdenum are found in small traces in the outer, silicate-layered layers of the two planets that provide decisive clues. Isotopes refer to different types of the same element, differing only in their atomic weight.
Scientists believe that these and other metal isotopes were not evenly distributed in the early solar system. Conversely, their frequency depends on the distance from the sun. Isotope frequencies provide information about where a body’s building material originated in the early solar system. Researchers use two types of meteorites specifically for the original isotope presence in the outer and inner solar systems. These rocks typically find their way to Earth from the asteroid belt between the orbits of Mars and Jupiter. Since the beginning of the solar system they have been considered a largely unchanged object.
When carbonaceous chondrites containing small amounts of carbon appeared on the other side of Jupiter’s orbit, they were transferred to the asteroid belt as a result of the influence of the growing gas giant, carbon dioxide non-carbonaceous relatives, real children of the inner solar system. The exact isotope composition of the Earth’s accessible, outer rock layers and the two types of meteorites have been researched for some time, and so far there is no comparable detailed analysis of the Martian rocks.
In their current study, the team studied samples of 17 Martian meteorites that could be assigned to six regular Martian rocks. In addition, scientists for the first time followed the path of three different metal isotopes. Samples of Mars meteorites were first pulverized and chemically pre-treated. With the help of a multi-collector plasma mass spectrometer at the Institute for Planetology at the University of Munster, researchers discovered small-scale titanium, zirconium and molybdenum isotopes. A computer was then used to simulate the ratio of construction materials found today to carbonaceous and non-carbonaceous chondrites to reproduce the measured values.
Results show that the outer rock layers of Earth and Mars are somewhat similar to the carbonaceous chondrites of the outer solar system. Their share of the original building materials on both planets is only four percent. “If the predecessors of Earth and Mars had collected dust mainly from the outer solar system, this value would have been almost ten times higher,” said Professor Dr. Thorsten Kleine of Mnster is also the director of the Max Planck Institute for Solar System Research in Gttingen. “Therefore we cannot confirm this theory of the formation of inner planets.”
But the composition of Earth and Mars does not exactly match the meaning of non-carbonaceous chondrites. Sample calculations suggest that other, different types of construction materials must be involved. “This third type of building material must have appeared inside the solar system. This can be inferred from the isotopic composition shown by our calculations,” Burkard explains.
Since the rock masses from very close to the Sun were not scattered on the asteroid belt, they were almost completely absorbed by the inner planets. They do not occur in meteorites. “It’s about lost building materials, we don’t have direct access today,” Klein said. The surprising discovery does not change the results of the study of theories about planetary formation. “Earth and Mars are mainly objects in the inner solar system that go well with the formation of planets from large body clusters in the inner solar system,” Burkard emphasizes.
The panel reports its findings in a special article in the journal Scientific advances Has appeared.
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