A discarded rocket stage, set adrift by the invisible hands of solar winds and gravitational currents, will complete an unplanned journey by striking the Moon near Einstein Crater on Wednesday morning — a reminder that even our most carefully calculated departures can find unexpected destinations. The 4,000-kilogram Falcon 9 upper stage, launched in January, was meant to pass harmlessly into the void, yet the cosmos had other intentions. In its unintended arrival, science finds an opportunity: a rare artificial impact that may illuminate how humanity must reckon with the debris it leaves behin