Seems to me that the only people who talk about "spinning ball earth" are the flat-landers. So, this challenge is basically open to flat-landers only, who don't seem to want to prove curvature and motion of such "spinning ball earth," as shown by their lack of ability to describe what "spinning ball earth" is, or how it is part of anything other than the second pipe-dream that flat-landers have.

Flat-landers seem to have two basic ideas about the earth: A) that the earth is flat; B) that the earth is a spinning ball. Neither of these is accurate, and people other than flat-landers don't understand Earth in either of these ways.

This is what makes this topic and challenge only open to the handful of people who are flat-landers.