Then why does Nofthath mention that Copernicus condemns flat earth in the first page?
Why would Copernicus have to mention flat earth in the 1500's if EVERYONE knew it was a ball?
That's a good question, which has not been answered.
If "everyone knew that the earth was a ball," then the flat earth would not have to be mentioned. Though I suppose that the idea of who "everyone" is, is to mean only those who are highly educated in mathematics and physics, since they are supposedly the only ones who are qualified to address the subject. They believe that they maintain the right to speak for "everyone," even if not everyone agrees with them.
Catholics who do not understand highly advanced science aren't allowed an opinion, and therefore they can't be counted as "everyone." In fact, they don't count at all. Those who use scripture to show a flat earth, as the Fathers did, don't count, since they (we) were relying on Scripture, which has been "corrected" by science.
And as "everyone" knows, science is always right. Science is the new religion, and it requires obedience to its dogmas.