I discovered it by simple observation, then researched it out. The stars only rotate over my house, they do not move. Year round is all the same, which is impossible in a spinning wall.
I can see for 30 miles over 180 degrees, My house should be sitting on a 300 foot high spot as I am located in the middle of a 30 mile view, 1000 feet above a river that is running with only 37 feet of drop to the ocean 70 miles away. The Moon is self illuminating as it is totally even in its light source throughout all phases. A ball reflector would reflect a hot spot. The horizon always rises to eye level from sea level to over 100,000 feet, this is impossible on a spinning ball.