Physics of the Impossible uses topics of speculative technologies to introduce topics of fundamental physics to the reader/listener/viewer. The topic of invisibility (cloaking), for example, becomes a discussion on why the speed of light is slower in water than in vacuum, which leads to a discussion of newly developed composite materials. Trekkian phasers becomes a lesson on how lasers work and how laser-based research is conducted. Technological advances we take for granted today were, as little as 150 years ago, thought to be ridiculously impossible. No less an authority than William Thomson, Lord Kelvin stated publicly that heavier-than-air flying machines were impossible, X-rays were a hoax, and that radio had no future.