Image: Artist's impression of a Mercury-sized body that smashed into Earth early in the solar system's history. Credit: Image by A. Passwaters/Rice University based on original courtesy of NASA/JPL-Caltech When a Mercury-sized body smacked into the young Earth 4.4 billion years ago, the cosmic collision likely made carbon more available for life to thrive today, a new study suggests.
The finding would explain a paradox puzzling scientists, which is how our planet still has carbon on the surface when it should have disappeared long ago. Theories suggest that early carbon on the surface would have boiled into space, or would have been stuck in the planet's core.
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"The challenge is to explain the origin of the volatile elements like carbon that remain outside the core in the mantle portion of our planet," said Rajdeep Dasgupta, who co-authored the study with lead author and former Rice postdoctoral researcher Yuan Li, in a statement.
Previously, some studies suggested the carbon could have come from meteorites, which are small rocks that whiz around the solar system and occasionally crash into Earth. But further study revealed some problems with the theory.
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