The research was led by Assistant Professor Haiyang S. Wang and Professor Anders Johansen, researchers from the Center for Star and Planet Formation<\/a>, part of the Globe Institute at the University of Copenhagen. They were joined by researchers from the Institute for Particle Physics and Astrophysics<\/a> at ETH Z\u00fcrich, the Nevada Center for Astrophysics<\/a> (NCfA), the Lunar and Planetary Laboratory<\/a>, and multiple universities. A paper detailing their findings was published in the scientific journal Nature Astronomy<\/a>. <\/p>\n The team’s approach focuses on specific elements located in the crust and mantle of Earth and Mars. Specifically, they focused on volatile elements like sodium, zinc, and potassium, elements that have relatively low melting points and evaporate at high temperatures. By analyzing the abundance of these elements, scientists are able to determine what processes the planet underwent during formation.<\/p>\n \u201cIt is a major detective job to figure out what happened back then when most of the evidence disappeared long ago,” said Johansen in a Globe Institute press release<\/a>. “But even after 4.5 billion years, the compositions of Earth\u2019s and Mars\u2019 mantles remain the same. You can think of them as an imprint of the formation process.”<\/p>\n Combined with advanced statistical modeling, they then calculated the most likely formation scenarios for the two planets. Their results demonstrated that volatile elements are lost from pebbles as they travel toward a planet\u2019s surface. Based on their relative abundance on Earth and Mars, this suggests that the two planets formed in different ways: Mars formed primarily through planetesimals colliding while Earth began largely as two protoplanets that grew through pebble accretion. As Wang summarized:<\/p>\n The most surprising result was that Earth and Mars appear to have formed in different ways. You might have expected that two planets formed side by side in the same solar system would share a more similar formation history.<\/p>\n At least 75 percent of Earth\u2019s mass appears to originate from two young planets, known as protoplanets, that grew large by accreting pebbles, while planetesimals contributed up to 25 percent. In contrast, roughly three-quarters of Mars\u2019 mass appears to come from planetesimals, with the remaining quarter originating from pebble accretion.<\/p>\n The researchers stress that their results are based on statistical modeling that contains uncertainties. These include the assumption of the chemical composition of the young Solar System’s accretion disk that would eventually form the planets. In addition, based on Mars’ similarities to Earth, it was also assumed that the planetesimal building blocks were chemically similar to the asteroid Vesta. <\/p>\n Lastly, it is traditionally assumed that volatile elements are lost more efficiently during pebble accretion than during giant impacts. But as Wang noted, even after the results are adjusted for these assumptions, the main conclusion remains the same:<\/p>\n The exact percentages may vary somewhat, but our analyses consistently indicate that Earth and Mars formed in two different ways. Our method provides a more precise and direct way of understanding planet formation than the more widely used isotope-based approach, which can often be interpreted in multiple ways.<\/p>\n What’s more, a better understanding of the formation pathways of rocky planets could help inform the ongoing search for habitable exoplanets. The Nancy Grace Roman Space Telescope<\/a>, which launched on August 30th, is equipped with a Wide Field Instrument<\/a> and a field of view that is at least 100 times larger than that of the Hubble Space Telescope. <\/p>\n![\"An](\"https:\/\/www.newsbeep.com\/nz\/wp-content\/uploads\/2026\/10\/eso1436f-1024x683.jpg\"\/)
<\/a> An artist’s depiction of a protoplanetary disk in which planets are forming. Credit: ESO\/L. Cal\u00e7ada<\/p>\n![\"Earth](\"https:\/\/www.newsbeep.com\/nz\/wp-content\/uploads\/2026\/10\/Earth-and-Mars-interiors-1024x409.jpg\"\/)
<\/a> Earth and Mars are both differentiated bodies, meaning they’re made up of different layers of material with different densities. Credit: (Earth) Kelvinsong, (Mars) NASA<\/p>\n![\"This](\"https:\/\/www.newsbeep.com\/nz\/wp-content\/uploads\/2026\/10\/eso1629e-1024x656.jpg\"\/)
<\/a> This artist\u2019s impression shows the planet Proxima b orbiting the red dwarf star Proxima Centauri, the closest star to our Solar System. Credit: ESO\/M. Kornmesser.<\/p>\n