Science for me is whatever I want it to be. Granted, some things cannot be done at our current level of development, but I do not think that means they are completely impossible. Once upon a time, humans thought the earth was the center of the universe, and that was science for them. Today we know more. But knowing more is never knowing all, everything thing we discover leads to a new science to research. That is the reality of science. It changes as we gain a greater understanding of the universe. Maybe someday we'll find out that the speed of light isn't an absolute speed limit after all, or that gravity can be reverse (antigravity) or something similar. Then the text books are re-written, as they have been so many times beforehand.