Many of my favourite stories feature time travel. I think they fascinate not just me but many people because our relationship with time itself is mysterious and deeply personal. There are other forces in the physical world for which we have gleaned enough understanding to manipulate and tinker to better suit our needs. We’ve learned about the intricacies of the atom, in particular the movement of electrons. You’re probably using electromagnetism to read these words off a screen. We use chemical knowledge in everything from transportation to better…