What about the Click and Clack theory?

Why couldn't it have been something two guys from Cambridge, MA welded together in their spare time? They invented the drive, built the ship and are using it to play pranks on people.

That theory would fit the observations as well as yours and would not require interstellar travel.

Or even more intriguing, the CIA could be directly projecting these images onto the receptors of your optic nerve. Have you been forgetting to wear your tin foil hat?

;-)

ps, I read the "tinfoil hat" thing to Carol and she rolled her eyes.

LOL