From the Atlantic
...Ever since Apollo astronauts toted chunks of the moon back home, the story has sounded something like this: After coalescing from grains of dust that swirled around the newly ignited sun, the still-cooling Earth would have been covered in seas of magma, punctured by inky volcanoes spewing sulfur and liquid rock. The young planet was showered in asteroids and larger structures called planetisimals, one of which sheared off a portion of Earth and formed the moon. Just as things were finally settling down, about a half-billion years after the solar system formed, the Earth and moon were again bombarded by asteroids whose onslaught might have liquefied the young planet—and sterilized it.
Geologists named this epoch the Hadean, after the Greek version of the underworld. Only after the so-called Late Heavy Bombardment quieted some 3.9 billion years ago did Earth finally start to morph into the Edenic, cloud-covered, watery world we know.But as it turns out, the Hadean may not have been so hellish. New analysis of Earth and moon rocks suggest that instead of a roiling ball of lava, baby Earth was a world with continents, oceans of water, and maybe even an atmosphere. It might not have been bombarded by asteroids at all, or at least not in the large quantities scientists originally thought. The Hadean might have been downright hospitable, raising questions about how long ago life could have arisen on this planet.
“Although, if you go back to the original Greek Hell, Hades, you had to cross a river. It’s a cool, wet place. So maybe the joke is on us,” says Mark Harrison, a geologist at the University of California at Los Angeles...
...“So maybe the Hadean was not so Hades-like,” Reimink says.
Wadhwa says lunar samples and zircon samples are so limited that we still can’t paint a full picture of the Earth’s turbulent early days. In one sense, everyone might be a little bit right. Earth might have been nice and calm in the time between major impacts. Or some areas might have been molten, while some areas might have been solid and covered in oceans, she says.
One thing is clear, however: Harrison says there has never been any evidence to support the canonical hellish vision of magma lakes and tar-colored volcanos showered in fiery meteors.
“There is absolutely not a single scrap of observational evidence that requires that scenario ever took place. We as a scientific community created an origin myth that has no more intellectual value than 1 Genesis,” Harrison says. “Although we’re very quick to criticize those that operate on faith, that’s exactly what we did.”
...Ever since Apollo astronauts toted chunks of the moon back home, the story has sounded something like this: After coalescing from grains of dust that swirled around the newly ignited sun, the still-cooling Earth would have been covered in seas of magma, punctured by inky volcanoes spewing sulfur and liquid rock. The young planet was showered in asteroids and larger structures called planetisimals, one of which sheared off a portion of Earth and formed the moon. Just as things were finally settling down, about a half-billion years after the solar system formed, the Earth and moon were again bombarded by asteroids whose onslaught might have liquefied the young planet—and sterilized it.
Geologists named this epoch the Hadean, after the Greek version of the underworld. Only after the so-called Late Heavy Bombardment quieted some 3.9 billion years ago did Earth finally start to morph into the Edenic, cloud-covered, watery world we know.But as it turns out, the Hadean may not have been so hellish. New analysis of Earth and moon rocks suggest that instead of a roiling ball of lava, baby Earth was a world with continents, oceans of water, and maybe even an atmosphere. It might not have been bombarded by asteroids at all, or at least not in the large quantities scientists originally thought. The Hadean might have been downright hospitable, raising questions about how long ago life could have arisen on this planet.
“Although, if you go back to the original Greek Hell, Hades, you had to cross a river. It’s a cool, wet place. So maybe the joke is on us,” says Mark Harrison, a geologist at the University of California at Los Angeles...
...“So maybe the Hadean was not so Hades-like,” Reimink says.
Wadhwa says lunar samples and zircon samples are so limited that we still can’t paint a full picture of the Earth’s turbulent early days. In one sense, everyone might be a little bit right. Earth might have been nice and calm in the time between major impacts. Or some areas might have been molten, while some areas might have been solid and covered in oceans, she says.
One thing is clear, however: Harrison says there has never been any evidence to support the canonical hellish vision of magma lakes and tar-colored volcanos showered in fiery meteors.
“There is absolutely not a single scrap of observational evidence that requires that scenario ever took place. We as a scientific community created an origin myth that has no more intellectual value than 1 Genesis,” Harrison says. “Although we’re very quick to criticize those that operate on faith, that’s exactly what we did.”
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