collision between Earth and Théia, an impactor the size of the planet Mars. The outlines of this catastrophic scenario are today validated by most astronomers. But the timing of the collision continues to be debated. And according to researchers from the German Center for Aeronautics and Astronautics (DLR), our planet would have been violently struck by Théia 4.425 billion years ago – to within 0.025 billion years. It’s only 140 million years after the birth of the solar system. But still 85 million years later than what astronomers previously thought. “Data-reactid =” 12 “> The Moon would have formed from the debris of a collision between Earth and Théia, an impactor the size of the planet Mars. The outlines of this catastrophic scenario are today validated by most astronomers. But the timing of the collision continues to be debated. And according to researchers from the German Center for Aeronautics and Astronautics (DLR), our planet would have been violently struck by Théia 4.425 billion years ago – to within 0.025 billion years. It’s only 140 million years after the birth of the solar system. But still 85 million years later than what astronomers previously thought.
ocean of magma which then covered the Moon – and the Earth – over a depth of 1,000 kilometers. If a rocky mantle quickly formed, it slowed the solidification of the rest of the ocean.“Our model shows that the moon’s magma ocean has taken nearly 200 million years to solidify”, says Maxime Maurice, DLR astronomer, in a communicated. “Whereas the old models gave a solidification period of only 35 million years. ““data-reactid =” 13 “> To arrive at this result, the astronomers used a new indirect method. They studied the process of solidification of theocean of magma which then covered the Moon – and the Earth – over a depth of 1,000 kilometers. If a rocky mantle quickly formed, it slowed the solidification of the rest of the ocean. “Our model shows that the moon’s magma ocean has taken nearly 200 million years to solidify”, says Maxime Maurice, DLR astronomer, in a communicated. “Whereas the old models gave a solidification period of only 35 million years. “
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In this diagram, the anatomy of the very young Moon. In gray, a rocky crust in formation and in yellow, an ocean of magma. In red and blue, the temperatures, more or less hot, at the heart of the Moon. © Maxime Maurice, DLR
Solidification models in the age of the Moon
To determine the age of the Moon, scientists had to go further. They calculated how the composition of silicate minerals rich in magnesium and iron – which formed during the solidification of the magma ocean – has varied over time. And they have highlighted a drastic change in the composition of the ocean of magma as it solidifies. A discovery that has …
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