It could be a hologram, projected from various government installations throughout the world. It could be a large, crudely painted balloon, held in place by helium and propelled by tiny sails and rudders (which is why it moves across the sky so slowly). Or, most likely, it could have been different things at different times and different places, depending on the technology available to the conspirators and the culture and beliefs of the population being deceived.

The hoax could easily have been imposed on a gullible world at many points in human history. Perhaps it began as a collective hallucination or a religious myth, or perhaps an especially bright star that came to be exaggerated over time. However the moon story started, early proponents of the hoax were swift to recognize how it could be exploited for their benefit, and shrewdly devised a scheme to use it to their advantage.