So you know that planet that crashed into Earth billions of years ago and formed the Moon? Geochemists who’ve been studying this phenomenon think that the impact occurred much earlier than we thought — which means that the Earth and Moon are also older than we’d calculated.
Before this new study,  which was recently presented at the Goldschmidt Geochemistry Conference in Sacramento, Earth’s atmosphere was thought to have formed about 100 million years after the solar system did. However, a team from the University of Lorraine in Nancy, France, have been analyzing xenon gas found in Australian and South African quartz dated to 2.7 and 3.4 billion years ago, respectively. Comparing the isotopic ratios of this gas to modern xenon allows the scientists to calculate around when the ancient planet Theia collided with Earth. Because the atmosphere would had to have formed after that impact (it would not have remained intact otherwise), these new estimates put the Earth’s atmosphere as having formed only 40 million years after the solar system, or 60 million years earlier than originally thought — give or take about 20 million years.
“This might seem a small difference, but it is important,” scientist Bernard Marty explained. “These differences set time boundaries on how the planets evolved, especially through the major collisions in deep time which shaped the solar system.”
Of course, it’s not possible to calculate an exact date for Earth’s formation — partly because it was so long ago that it’s difficult to pin down anything concrete, but also because she straight-up refuses to tell us. What else have you hiding, Earth? Is your mantle actually full of hibernating lizard people just as we always suspected? Reveal your secrets, you filthy planet!
Oh, also, sorry about all the filth. That’s on us.
(via Phys.org, image via NASA)
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