A new Nature paper suggests that the moon formed as a result of a more violent space collision than previously believed. The prevailing Moon-formation theory is that the Moon formed after a Mars-sized body grazed Earth in a relatively low-energy collision. New evidence implies that the impact was more “like a sledgehammer hitting a watermelon.”
“We need a much, much bigger impact to form the Moon according to our study,” explained Kun Wang, assistant professor at Washington University who is the lead author of the paper. “The giant impact itself should be called extremely giant impact.”
Tests of isotope signatures came back nearly identical, except for more of a heavy-potassium isotope in the lunar samples, which would have required incredibly hot temperatures to separate out. A violent collision between the Earth and the Mars-sized impactor could have caused those incredibly high temperatures. In this model, the temperatures were so high and the force so powerful that the impactor and even much of Earth vaporized on contact. That vapor then expanded out over an area 500 times the size of the Earth before finally cooling and condensing into the moon.
“Our understanding of the early solar system has changed,” said Wang. “It’s much more violent than we thought.”
The researchers will continue to study the Apollo lunar samples to try and pull yet more clues from them. Even now, they suspect that these samples that we’ve been holding on to for decades could have more secrets to reveal.
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Posted by: Soderman/SSERVI Staff
Source: Ria Misra/Gizmodo