Why is the Co-accretion theory generally considered insufficient to explain the Moon?
Answer
It does not explain the lack of iron in the Moon
The Co-accretion theory posits that the Earth and Moon formed simultaneously from the same cloud of gas and dust. If this were true, both bodies should have similar chemical compositions, including a comparable proportion of iron. However, the Moon has a significantly smaller iron core relative to its size than the Earth. The Giant-Impact Hypothesis solves this by explaining that the Moon formed primarily from the rocky, iron-poor mantles of the colliding bodies, while the metallic iron cores had already migrated to the centers of the planets prior to the impact.
Related Questions
What is the primary scientific name for the theory explaining the origin of the Moon?Approximately how large was the protoplanet Theia that collided with Earth?Which elements serve as isotopic evidence for the shared heritage of the Earth and the Moon?Why is the Co-accretion theory generally considered insufficient to explain the Moon?Approximately how long ago did the impact involving Theia occur?What do recent computer simulations suggest about the speed of the Moons formation?Why does the Moon lack water and other volatile compounds compared to the Earth?What became of the remnants of the protoplanet Theia after the collision?What does the angular momentum of the Earth-Moon system reveal about the impact?Why are fragments of Theia not easily found on the surface of the Earth today?