This is a recurring meme among flat earthers, but I don't think they've actually thought this through. If the earth is flat, why can't I see farther than 190 miles? Why can't I look over to night side of the disc and see the twinkling lights of distant cities? Why can't I, even with a telescope, see the “Great Ice Wall” of Antarctica? The horizon on a flat earth would look very different from what we actually see.