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Remove much of the Earth's mass. The giant impact hypothesis states that about 4 billion years ago, when Earth was but a wee protoplanet, a Mars-sized object dubbed "Theia" hit it at an angle of 4...
Answer
#1: Attribution notice removed
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System
·
2020-06-01T14:13:42Z (over 4 years ago)
Source: https://worldbuilding.stackexchange.com/a/8429 License name: CC BY-SA 3.0 License URL: https://creativecommons.org/licenses/by-sa/3.0/