In college, I was an Art major, but we still had to take two science classes. I chose astronomy as one of them, because I was well versed in the subject, and our textbook was Cosmos, a book I had read several times for fun anyway. Our professor was explaining to the class about black holes, and he incorrectly stated that the Schwartzchild Radius was the distance from one edge of the black hole to the other. A friend of mine gave me a confused look, so I whispered, “He means from the edge of the black hole to the center, not the other edge.” The professor loudly cleared his throat and said “you two, pay attention, what’s so important that you have to interrupt my class?” I looked at my notes and said “it can wait.” He got all huffy, and said “No, by all means, please, let’s hear it.” So I shook my head and said “I was just telling her that you were wrong, that the Schwartzchild Radius was NOT the distance from one edge of the black hole to the other, it was the distance from the edge of the black hole to the singularity. You know, like a radius.” The teacher stared at me for a second, and then turned back to the board. “As I was saying,” he continued, without acknowledging that I was correct and that he, a college science professor, had confused the definitions of radius and diameter.