Like fantasy and historical fiction, science fiction is as reliant on world building as it is on character and plot. If readers don’t find the setting convincing then they won’t read on.
So how do you get science fiction world building right?
Getting the Science Right
How far you need to worry about the science depends upon the sort of science fiction you’re writing.
For hard sci-fi like that of Kim Stanley Robinson, extensive research is needed. Readers are likely to be knowledgeable about science and expect the same from you.
This means creating planets whose geography is consistent with our understanding of how worlds form; settlements that have everything they need to function; spaceships that follow the laws of physics as they apply in space (think The Expanse rather than Star Trek); and so on.
If you’re writing at the softer end of science fiction – for example space opera in the style of Star Wars – then there’s less need to sweat all the details. There are obvious things you have to stick with, like people not breathing in space. But most important is consistency. If you’ve invented a form of faster than light travel, make sure that you know the rules you’ve created for it, that you’ve thought through the implications, and that you are consistent.
Some sci-fi needs realistic, well-researched science. All sci-fi needs a world that makes sense from one page to the next.
Getting the People Right
Once you’ve set up your universe you need to populate it.
Unless you’re writing in the very near future, the people in your setting should be different from the ones we know today. After all, they’re living in a different world and that will shape them. This can make your characters both more convincing and more interesting.
The Expanse offers great examples. Living on asteroid mines has led to people whose bodies are more vulnerable than if they had grown up in Earth’s stronger gravity. It also leads to a distinct accent, jargon, social hierarchy, and all the things that make a culture unique. More subtly, the events on Earth have shaped the attitudes and lifestyles of character coming from there.
With aliens, this is more extreme. Think about how their planet has shaped their bodies and their view of the world. What cultural differences stem from a different physiology? Can they speak the same words or eat the same food as humans?
This doesn’t mean that you reject everything familiar. Readers need to be able to identify with characters. Even the most alien should show a trace of personhood, something we can empathise with. The aliens in Arrival and the short story it is based on don’t even experience time as humans do, but they still show such human emotions as compassion and grief.
Just Enough Jargon
Specialist language is a powerful tool. It can be scientific terminology, the names of alien species, or the slang of a future culture. Dropping in this language hints at the depths of your setting.
Little bits are all you should use. Go too far and you’ll overwhelm readers with language they can’t follow.
Make sure that the first time you use a strange word there’s enough context for readers to work out its use and meaning. Whether it’s the angry, expletive-like tone with which someone shouts “frell” or an exposition on the role of midichlorians, this is needed to help readers learn the language. The more often you can avoid exposition for this the more subtle and easy to read the story will be, but sometimes you just have to explain.
Convincing Rather Than Realistic
All of this can be boiled down to one principle – you need to be convincing, not necessarily realistic.
Realistically, alien species might not be able to form words like our own, but for most sci-fi they need to be able to. Showing them struggling with the words makes this convincing.
Realistically, we may never travel faster than the speed of light, but if you use a consistent set of rules and jargon for this then readers will accept it.
Realistically, we may never be able to live on asteroids, but if you show how that would affect people then the characters living there will come to life.
As with fantasy and historical fiction, you’re creating a world that modern readers can accept, believe, and engage with. Use realistic details as long as they add to this. Use as much science as your target readers expect. But remember, you’re creating a fiction, but not a scientific paper. The way that the setting shapes the characters, not the minutiae of research, is what will make people care.