In the long story of humanity reaching outward into space, even our accidents leave marks. A SpaceX Falcon 9 upper stage, set adrift by solar forces and gravity after its 2022 launch, struck the Moon at extraordinary velocity this week — and South Korea's Danuri orbiter was there to witness the aftermath, transmitting images of a freshly darkened crater carved into terrain that had remained undisturbed for eons. The collision was unintended, but the record it leaves is permanent, and the scientific community is already gathering around it as an unexpected window into lunar geology.