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A new study finds the gases which formed the Earth's atmosphere as well as its oceans did not come from inside the Earth but from comets and meteorites hitting Earth during the Late Heavy Bombardment period. A research team tested volcanic gases to uncover the new evidence. They found a clear meteorite signature in volcanic gases which could not have contributed in any significant way to the Earth's atmosphere. Therefore the atmosphere and oceans must have come from somewhere else, possibly from a late bombardment of gas and water rich materials similar to comets.
According to the theory of the Late Heavy Bombardment, the inner solar system was pounded by a sudden rain of solar system debris only 700 million years after it formed, which likely had monumental effects on the nascent Earth. So far, the evidence for this event comes primarily from the dating of lunar samples, which indicates that most impact melt rocks formed in this very narrow interval of time. But this new research on the origin of Earth's atmosphere may lend credence to this theory as well. Until now, no one has had instruments capable of looking for these subtle signatures in samples from inside the Earth.
Source: universetoday
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Sam
