I don't understand why so many Science Fiction authors attempt push the limits of material science while clearly being almost entirely ignorant of it. For examp

I don't understand why so many Science Fiction authors attempt push the limits of material science while clearly being almost entirely ignorant of it. For example, carbon fiber composites do bend. You can make springs out of them. Also, if you could figure out how to manufacture anti-gravity thrusters at a scale large enough to use them on a space ship you'd probably win the Nobel.