I don't see that it would be particularly difficult to convince great numbers of people. In the (fairly) early days of the space program, there was an experiment done in which sodium ions were released into space in the vicinity of the earth. Large numbers of people were able to see the resulting display, over a wide area, as the ions fluoresced due to sunlight.
Isaac Asimov even wrote a sci-fi piece about it, called "Watch This Space" in which the Coca-Cola(or some generic cola) company paid someone at NASA to switch the orifice on the ion generator so it projected the company's name, in ***LARGE*** letters. Wouldn't it be interesting if Clark simply took such a generator, flew into space, and wrote "Superman" -- in cursive(!) -- in nice slow strokes? Wow!
Snave
