If you want to measure the diameter of the sun yourself, here's a simple way to do it. On a dark piece of paper, make four fine lines 1/16th of an inch apart, and tape the paper to the inside of one end of a shoebox. With a sewing needle, make a pinhole in the other end of the shoebox and hold it so the sun is shining through the pinhole and casting a small round image of itself on your marked paper. Accuracy matters here, so you want to measure the width of the spot within 1/32 of an inch. Now measure the inside of the shoebox from the marked paper to the pinhole. The rest is simple geometry:The length of the shoebox is to the width of the spot as the distance to the sun (93 million miles) is to the diameter of the sun. Astronomers with slightly more advanced equipment say the sun is 870,000 miles across. What did you get?