Hiya.

I am looking for an easily understandable proof that the sun's "rays" are essentially parallel by the time the reach Earth. What I need is something you can show a brainlet, without resorting to a lot of math and without making any prior assumptions about the distance to the sun. Something you can point to and say "Look, moron, they are fucking parallel."

Does /sci/ have anything? My Google-fu could only find some math-intensive proof using moon phases and trigonometry.