The gravity effects reach out a long way, however, and can affect matter around it, drawing it in. As the matter spirals into the black hole, local effects heat the matter up to incredible temperatures, which in turn makes it emit all sorts of radiation. That's why we think Cygnus X-1 is a black hole. In that scene, they try to establish Sellecca as a brilliant astronomer, but really they accomplished exactly the opposite. I personally found that a bit insulting.
Teaching is one of the most important aspects of astronomy.
You may not need a PhD to teach high school, but they implied that it was beneath her. I believe that teaching astronomy is pretty noble, and anyone who tries to teach it to high school students deserves a medal, not derision. He says he has the coordinates and it will only take a few minutes to point it. After his demand is met, he immediately gets live video feed of the asteroid from HST, showing the spinning asteroid clearly. Another densely-packed example of Bad Astronomy.