Scientists discover how Earth’s interior took shape in its first 100 million years

Scientists have discovered fascinating new insights into what Earth looked like before it was fully formed. A study led by Charles-Édouard Boukaré, physicist at York University, reveals that our planet’s essential features were established within its first 100 million years. Published in Nature, the research combines geochemistry with advanced computer simulations and sophisticated modeling techniques to show how Earth’s molten interior cooled and solidified into distinct layers that continue to shape its geology and tectonic activity today. These results challenge long-standing theories of planetary formation and provide a new perspective not only on Earth’s origins but also on how rocky planets across the universe form, evolve, and sustain potentially habitable conditions.According to a study published in Nature, Earth’s early history was defined by a violent and chaotic period. Instead of a stable planet, Earth was a vast magma ocean, a molten, turbulent mass surrounding a glowing core.For decades, scientists believed the planet’s lower mantle solidified slowly under immense pressure deep below the surface. However, Boukaré’s team discovered that many of the crystals which influenced the mantle’s chemistry actually formed closer to the surface at much lower pressures. This surprising insight reshapes our understanding of how Earth’s internal structure developed during its earliest epoch.The research team used multiphase flow simulations to model how molten materials cooled and separated within Earth’s interior. Some crystals sank, while others floated, creating distinct chemical layers that remain today. Boukaré likened this stage to childhood energy, noting that young planets, like children, behave chaotically due to their high energy. The study suggests that Earth’s lower mantle, responsible for plate tectonics, heat transfer, and magnetic field generation, was forged during this unstable youth. This finding highlights how turbulence in the planet’s first 100 million years left a permanent mark on its structure and behaviour.One of the most intriguing aspects of the study is the possibility that some crystal patterns preserve conditions from before Earth was fully formed. During this period, material was still accreting from the solar nebula, the cloud of dust and gas that birthed our solar system. If confirmed, these ancient crystals could represent geological features that predate Earth itself, offering one of the oldest records of planetary formation. This raises the exciting prospect that Earth carries chemical fingerprints from a time when it was still assembling from cosmic building blocks, potentially reshaping scientific understanding of planetary origins and evolution.The implications of this research extend far beyond Earth. By linking early thermal and chemical conditions to present-day planetary structures, scientists can better predict the evolution of other rocky planets such as Mars, Venus, and Mercury. This framework may also be applied to exoplanets orbiting distant stars, offering clues about their habitability, internal dynamics, and ability to generate magnetic fields. As Boukaré explained, knowing the starting conditions and key processes allows researchers to predict planetary evolution. This breakthrough provides a vital new tool for planetary science and the ongoing search for life beyond Earth.Also read | James Webb Space Telescope reveals stunning star-forming cluster Pismis 24 in Lobster Nebula