Space & Astronomy
Where did the Earth get all of its water from ?
By T.K. Randall
August 28, 2020 · 6 comments
Was the Earth's water here all along ? Image Credit: CC BY-SA 3.0 NikoLang
A new study has cast doubt on the prevailing theory of how our planet came to possess so much water.
For years, it was generally believed that most of the Earth's water was not present when our planet originally formed but instead arrived later via water-rich comets and meteorites.
This is because, due to the Earth's proximity to the Sun, it was thought that the temperature would have been too high for ice to have combined with rock and dust during the Earth's formation.
Now however, a new study by CRPG researcher Laurette Piani and colleagues has cast doubt on this idea by measuring the hydrogen content of certain types of meteorites.
The meteorites in question - known as enstatite chondrites - were chosen because their chemical make-up is much the same as the material that came together to form the Earth 4.5 billion years ago.
Surprisingly, they were found to contain quite a significant amount of hydrogen - enough to ensure that the newly formed Earth had more than enough water to cover the planet's surface.
"I was happy because it makes it nice and simple," said NASA planetary scientist Anne Peslier.
"We don't have to invoke complicated models where we have to bring material, water-rich material from the outer part of the solar system."
"So here, we just don't need Jupiter. We don't need to do anything weird. We just grab the material that was there where the Earth formed, and that's where the water comes from."
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