Authors including Nnedi Okorafor, Kim Stanley Robinson and Alastair Reynolds reveal what does, and doesn’t, go into creating their worlds

We’re in a weird time for the way the future looks; somehow House of Cards can slyly introduce a floating text-message interface to their present-day political drama without so much as blinking, but most of our iconic near- and far-future worlds run on tracks laid down well before the ’90s.