Sean Carroll = theoretical cosmologist, popular science writer
Elon Musk = Engineer and entrepreneur with some crazy ideas that actually happen! See SpaceX (private space delivery/ travel/ exploration), Tesla (most successful electric car company), SolarCity (major solar initiative), artificial intelligence, and more!
Ben Goldacre = Doctor and skeptic, fighting a hugely successful battle in getting medical data from Pharmaceutical companies. A bona fide quack-buster