How to Create a Fictional Galaxy to Intrigue Sci-Fi Audiences
- Mar 9
- 4 min read
If your sci-fi lives outside the Milky Way, you may be thinking about worldbuilding galaxy aspects. But space is vast, it can be difficult to create something meaningful. Unless you focus on what’s important for your universe.
This is a primer on how to create a fictional galaxy.
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How to Create a Fictional Galaxy’s Interstellar Space
Because space is so immense, it’s helpful to define the extent of your narrative.
Does the story touch multiple galaxies or just one planet? Several planetary systems or just a couple stars?
Once you conceptualize how much space your story encompasses, you can begin worldbuilding galaxy elements.
Let’s say a storyline is about a delivery pilot who travels from one planet to the nearest one. And, in this story, the character only spends time on the docks. Worldbuilding complex terrain and climate on the other side of the planet probably isn’t necessary.
But, maybe your plot goes off course. That same delivery pilot accidentally drifts out to the edge of the galaxy. Or your characters like the adventure or fortune inherent to the dangers of interstellar space.
If that’s your narrative need, you’ll want to consider what could be notable about the space between galaxies.
Play with molecular clouds and gases. Gravity and radiation. And conceptualize how much area you’re working with. What’s the distance between this galaxy’s edge and the next? Is that space easily traversable given the universe’s technology?
Within my Drifting Amalgams universe, interstellar space travel is not particularly common. Most travellers have little reason to leave the galaxy. But I developed some details about interstellar space anyway because they help define an important influence within the story world.
The most powerful company in the galaxy, IndServ, has found a way to capture and refine the gas and dust in interstellar space. They refine it into fuel.
I can use this detail to create conflict by limiting access to that fuel.
But, because my characters don’t spend any time in interstellar space, I haven’t bothered to develop much beyond the idea that it contains valuable resources.
The rest of the galaxy, however, I constructed more thoroughly.
Worldbuilding Galaxy Objects of Narrative Interest
Once you know the outer limits of your narrative universe, you’ll need to think about what’s inside those limits.
Again, this is something that should be guided by the needs of the story. Because this is the type of worldbuilding exercise that could easily engulf a writer.
So begin with at least a surface idea of your plot. Then, work on developing that plot through worldbuilding.
Let’s say that delivery pilot from earlier veers off course, but doesn’t go as far as the edge of the galaxy. The peril they encounter within the galaxy would be at the crux of the story. The conflict to get the audience invested.
You’ll want to consider planetary and stellar threats, but there are many other challenges that you can explore.
These could include stars, dust, gases, comets, asteroids… and maybe other people.
To simplify your brainstorm, start with something like the relative metal content, density, and temperature of the gas in the galaxy.
Now, look at the composition, structure, and attenuation curve of the galaxy’s dust.
And now, bigger objects.
How large and numerous are asteroids? Comets? And interestingly, what does this mean for the look and feel of the galaxy or planet formation?
Maybe there are many asteroids or comets. And the technology of your universe is advanced. Maybe, as with the Drifting Amalgams universe, the astronomical objects are composed of minable material.
This is another detail I developed to show the influence IndServ has within the galaxy. Comets are abundant in water. Asteroids are rich in metals. And IndServ not only extracts these resources, but they use them to build and resupply ships. An idea that serves as a base for IndServ’s growth as a galactic corporate power.
So I didn't just worldbuild for the sake of creation. I used it as a means of focusing my thoughts on how the company’s influence could affect everyday people.
But that begs the question: Whose ships are they building and resupplying?
How to Create a Fictional Galaxy with Suitable Space Travel
Realistically, the most common reason for worldbuilding galaxy aspects is space travel.
And a lot of the focus for the average space opera or space-included sci-fi is on spacecraft. But there are many details that can be developed in conjunction with or outside of ship design.
Maybe there’s one specific anomaly that you want to write around. This could be something like your basic black-hole plot device.
Or maybe the drama is about other people in space.
While a spacefarer is not likely to randomly bump into another traveller, a plot can center on forced interaction. Maybe two people, pirates, or companies are competing.
Perhaps, instead, there are dangers that are not predictable–like solar particle events. Something that makes space travel curious or dangerous on a narrative level.
To figure out what space travel looks like for your characters, begin by defining everyday space existence. What is space travel like for the average crew?
Then, extend your thinking to describe things that may be considered threatening. Can these threats be overcome? How?
Conversely, what factors make space travel leisurely or pleasant? Is this the case for everyone, or does something (or someone) ease the burden for some? Maybe a community of space travellers assist each other.
Or resupply vehicles are on call for those in need. Kind of like a tow truck.
By now, you won’t be surprised to learn that this is the detail I created for my Drifting Amalgams universe. Space travel in my world is so common that breaking down or “running out of gas” are well-known problems.
That’s why in-space supply and refuel are available for those in need. Of course, being a good samaritan’s not usually the best story device. So most resupply, refueling, and water replenishment services come at a price in my stories.
But that’s something I’ll talk about when I worldbuild space lanes in a couple weeks.
Until next time, stay inspired.
