Planetologists from the University of St. Andrews examined the isotopic composition of zinc in meteorites formed in the internal and external parts of the solar system, and the results show that much of the volatile matter of the Earth ' s atmosphere was formed away from our planet and was carried by space objects.
In their work published in the journal Icarus, the authors studied the isotopic composition of zinc in carbon hondrits, the most common type of meteorites formed in various parts of the solar system, and the study revealed significant differences in the variety of chemical elements of objects, while the composition of zinc isotopes on Earth is an intermediate option between meteorites formed inside and outside the asteroid belt.
The results show that between 5 and 6 percent of the Earth's mass consists of materials formed in the outer region of the solar system, a part of our planetary system containing gas giants.
Scientists note that although only a small fraction of the Earth's total mass came from the outer solar system, this material should be enriched by volatile matter; for example, an analysis of zinc isotopes shows that at least 30 per cent of this volatile substance is foreign; planetologists believe that for more volatile elements than zinc, the proportion will be even higher.
The origin of the volatile elements present on Earth is fundamental to the understanding of the evolution of our planet; these elements are crucial to the emergence of life; this study will help scientists understand how planets are formed and where other inhabited worlds are to be found.
Research like ours gives us a new idea of how and where the planets accumulate the kinds of elements that are crucial to sustaining life, but in a broader sense they give us more clues about how our early solar system behaved.