Everything. All my knowledge is embedded to my writting.
I like educating people but I am careful not to make it boring. I am also careful to help distinguish between fiction and reality. For example, in science fiction novels people travel to other galaxies and they go faster than the speed of light. In reality this is impossible. In the first place it would take months to reach the speed of light without getting killed by G force of acceleration.
It is also cool how space ships make a sudden stop reducing speed but in reality the laws of physics would kill us since our bodies would keep moving and even if our bodies are somehow stopped together with the ship our organs would keep moving.
Now writing this would make any sci-fi boring so explanations are usually avoided.
Point is when you write you can include accurate facts but when doing it in a story you have to keep a way of making it interesting.