What is hard science fiction, versus soft science fiction?
That is not an easy question to answer, but here’s an attempt. In hard science fiction, technology is not magic. It has extremely firm limitations placed onto it based on what the writer’s research reveals to be true and/or possible. Some leeway is allowed for storytelling purposes (usually, faster-than-light travel is the biggest one that science deems impossible but storytellers love), but most of the rules fall exactly into what is actually possible. As an example, there’s a webcomic called Schlock Mercenary. Most of the technologies (except for the wormgates) featured in the comic are actually things which might be possible to built in the next few centuries. Contrast this with soft science fiction. It’s another fuzzy label that’s often lobbed around without actual good reason; some claim it applies to science fiction that focuses heavily on the characters or society, but generally the consensus that I have encountered is that soft science fiction stories have science merely as a f
