The Moon Assembled from a Swarm of Earth's Fragments ⚡ экспресс
It turns out that the Moon may have been born not from one monstrous collision, but from many small 'splashes.' The early Earth was bombarded by asteroids, ejecting chunks of its mantle. Those that flew in the direction of the protolunar cloud's rotation stuck to it, like snowflakes to a snowball, while the ones going the opposite way fell back. This explains why the Moon is poor in iron and more similar to Earth's crust.
When countless asteroids pummeled the young Earth, they tore chunks from its mantle. These fragments spiraled in a cosmic disk around the planet and, like a snowball in a blizzard, fused into the Moon.
The same scenario applies to Pluto's moon Charon and hundreds of binary asteroids in the Solar System. Importantly, fragments moving in the same direction as the disk's rotation stayed in orbit and contributed to growth, while those coming the opposite way fell back. Thus, some material destined for the Moon scattered over Earth: we walk on rocks that once traveled through space.
🎯 The Moon is iron-poor, which long didn't fit the single-impact hypothesis: such a collision would have mixed crust and mantle material, enriching the satellite. The new multi-impact model naturally solves this puzzle.