The Expanse should just change their post credits for each episode to include a list of homework questions. Seriously—there are so many great things to explore in this hard science fiction show. In a recent episode, one of the large spaceships (the Navoo) rotates in order to create artificial gravity (that's not really a spoiler). How about some questions and answers about this giant spinning spaceship? How do you make artificial gravity? Let me get right to it.