Earth and Mars: Built from different cosmic recipes

Credit: CC0 Public Domain Four and a half billion years ago, Earth and Mars were born in the rotating cloud of gas and dust that would eventually become our solar system. Researchers at the University of Copenhagen have reconstructed the earliest stages of the planets' formation by analyzing their chemical composition. The study suggests that Earth and Mars formed in different ways, with Earth likely involving pebble accretion and Mars relying more on planetesimals. The findings are presented as a bulleted list: "- Earth and Mars formed in different ways, with Earth involving pebble accretion and Mars relying more on planetesimals. - 75% of Earth's mass comes from protoplanets that grew by accreting pebbles, while 25% came from planetesimals. - Mars' mass is mostly from planetesimals, with 25% from pebble accretion. - The chemical composition of Earth's and Mars' mantles remains the same after 4.5 billion years, providing an imprint of the formation process. - The study uses computer models to determine the most likely formation scenarios for the planets. - The research highlights the importance of volatile elements in revealing the formation processes. - The study supports the hybrid model of planet formation, offering a more explicit explanation of how Earth and Mars formed. - The findings could help in understanding how other planets form and in the search for habitable planets. The study is published in Nature Astronomy. The researchers emphasize that their models contain uncertainties, but the main conclusion remains consistent. The study's implications are significant for planetary science and the search for life-supporting planets.

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