Moon’s Metal-Rich Craters Challenge Popular Theories About Its Origin

schwit1 shares a report from UPI: The most popular theory of the moon’s origins contends the satellite was formed when a Mars-sized object collided with Earth, vaporizing large portions of Earth’s upper crust. While Earth’s upper crust is poor in metals, new research — published Wednesday in the journal Earth and Planetary Science Letters — suggests the moon’s subsurface is surprisingly metal-rich, undermining the satellite’s proposed origin story. Authors of the new study suggest planetary scientists consider alternative theories for the moon’s formation. It’s possible the collision that forged the moon was more violent than scientists thought, gouging out even deeper portions of Earth’s crust and mantle. It’s also possible the moon experienced an unusual cool-down process, post-collision — a process that left the moon with large concentrations of metal.