Let's say you're in an airplane, and you fly around the world in the northern hemisphere, 30 degrees north of the equator, staying at 30 degrees the entire time. The FErs say that you actually turn your plane. Fine, that actually makes sense. You record the distance it takes to get back to the place you started. Now, you travel 30 degrees south of the equator, and fly around the world again, staying at 30 degrees from the equator again. Once again, you record the distance traveled. In the round earth model, the two distances are identical, 3607 miles. This has been tested, and the distances are the same. Using ancient formulae, it is possible to calculate the circumference of the earth from latitude, and it is possible using an airplane and using the stars. It is easy to find the results for these experiments online. For 30 degrees north and south, the results are the same. Based on the FE, the two results should be much different. Take a simple look at the FE map to see what I mean (can't load images on my blackberry, sucky connection.) Explain that, FErs. The results should be different, but strangely aren't.