There are explanations of experiments you can do yourself folks, just read Zetetic Astronomy by Dr. Samuel Rowbatham. He has about 300 pages worth, done in the 1800s, which means they should be repeatable and easier to do with better equipment now. Prove the curvature to yourself.. Once you try that one you’re going to go hmmmmm…This is easy to figure out. No rocket scientist credentials are required..