You've got a plane that's thousands of feet up in the air, going at hundreds of miles an hour, and you're trying to drop an object, a bomb, towards some stationary target in the face of all kinds of winds and cloud cover and all kinds of other impediments.
Tenemos un avión a miles de metros de altitud que viaja a cientos de kilómetros por hora, e intentamos lanzar un objeto, una bomba, hacia un objetivo fijo en medio de todo tipo de vientos, nubosidades, y toda clase de impedimentos.