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space rocks

New research suggests we were wrong about the origins of the moon

Is everything we know about how the moon was formed a lie?

Until the last decade, everyone pretty much agreed on the most likely theory on the formation of the moon. Back when Earth was young, a huge rock crashed into it, taking part of the Earth's mass with it and forming it as a satellite that orbits our planet. The "Giant Impact Hypothesis," as it's called, makes some sense — but recent analysis of moon rocks have put some holes in that theory.

Now, new research suggests a slightly different story for how the moon came into being: Maybe it was hot magma.

At the time of the "Giant Impact," this new theory says, the Earth may have been really, really hot — so hot that large parts of it were entirely molten. If the Earth was covered in an "ocean of hot magma," then it makes sense that the impact from another space rock could have actually launched huge amounts of the molten matter into space, thus forming the moon, NBC News explained. That would answer the question of why so much of the moon's makeup is so similar to Earth, rather than the other rock that supposedly formed it.

The research into magma's effect on the moon, published on Monday in Nature Geoscience, suggests that instead of hitting our planet full-on, the rock that crashed into it simply knocked it aside and went on its way. But under the force of such an impact, enough magma was propelled away from the surface of the Earth to form the entirety of the moon.

"The magma ocean is one of the most important things for the moon-forming giant impact," said the study's lead author, Natsuki Hosono. Learn more about this new development at NBC News.