Downvote me to oblivion, but riddle me this Neil DeGrasse Tyson. If the Earth is an 'oblate spheroid' (it used to be a perfect sphere, you've seen the pics, right?) with a roughly 25,000 mile circumference, then why do all the curvature calculations fail? The rate of curve on a sphere that size is 8" x the number of miles squared and modern optics have completely debunked that. We can see too far. There is no curve. Therefore...