One of the odd things about science fiction is that the people most likely to underestimate the scale of space are science fiction readers.
We spend so much time in fictional universes where ships leap between stars, where empires span a thousand worlds, where a fleet can arrive “just in time,” that we quietly absorb the idea that interstellar distances are large, certainly, but manageable.
They are not.
The recent demonstration of the distance between Earth and the Moon made even me stop and stare. We know, intellectually, that the Moon is far away. Yet seeing all the planets fit comfortably between Earth and the Moon, with room to spare, is startling. It reminds us that even the distances inside our own solar system are vast beyond ordinary human intuition.
And then there are the stars.
The nearest star beyond our Sun, Proxima Centauri, is about 4.2 light years away. If you could travel as fast as the Voyager probes, it would take roughly 75,000 years to get there.
That is not a long trip. That is civilization-endingly far.
Science Fiction Shrinks Space
Science fiction routinely cheats. It has to. Without some method of making space smaller, most of the stories we love could not exist.
This is why faster-than-light drives, wormholes, jump gates, folded space, hyperspace, portals and other miraculous technologies are so common in science fiction. They are not there because writers are careless about physics. They are there because otherwise the stories become almost impossible to tell.
Orson Scott Card once argued that the first thing a science fiction writer must decide is how people travel between the stars. Everything else follows from that answer.
He is right.
The speed of travel determines the kind of civilization you can have, the sort of politics that are possible, and even the kinds of stories you are able to tell.
If It Takes One Hundred Years
Suppose there is no faster-than-light travel.
Suppose the nearest colony world is a century away.
Now your story is not about a galactic civilization. It cannot be. A hundred years is too long for trade, government, rescue or war.
Instead, your story becomes about generation ships, suspended animation, isolated colonies and cultures that drift apart. Messages arrive decades after they are sent. A child may leave Earth and arrive at another star as an old woman. A colony may lose contact entirely and become something utterly different.
This is the territory of “mundane” science fiction and of novels such as Tau Zero or Aurora. It is also the territory of generation-ship stories, including my own Endurance sequence under the Tracy Cooper-Posey name.
These stories are often about sacrifice, inheritance and loneliness. The distances matter because they cannot be overcome.
If It Takes Weeks or Months
Now suppose travel between stars is difficult but possible. Perhaps ships can move faster than light, but not very much faster. A journey might take weeks, months or years.
This creates a very different kind of story.
Now there can be trade and diplomacy, but only slowly. Colonies are still semi-independent. Governments are loose federations rather than tightly controlled empires. Fleets can be sent, but too late to prevent the first disaster. Smugglers, frontier settlements and distant outposts become important because the edges of civilization are genuinely remote.
This is the territory of much military SF and frontier SF. Even within a single solar system, The Expanse captures this feeling brilliantly. Distances are not insurmountable, but they still shape everything. Mars, Earth and the Belt are close in astronomical terms and still far enough apart to create political and cultural separation.
A setting where stars are weeks apart feels more like the age of sail. News travels slowly. Reinforcements arrive late. Local rulers gain power because the capital is too far away to interfere quickly.
If It Takes Hours
Reduce interstellar travel to hours or days and the shape of the story changes again.
Now there can be real interstellar nations. Trade becomes practical. Families can move between worlds. A central government can keep control because it can send officials, armies and inspectors quickly.
At this point, science fiction starts to resemble modern life on a larger scale. The stars become cities connected by airlines.
This is where much space opera lives. It allows for adventure across many worlds without making those worlds impossibly disconnected from each other.
The difficulty, of course, is that once travel becomes this easy, writers have to remember what they have done. If it only takes six hours to cross ten light years, then empires should be stable, trade should be immense, and a distress call should not go unanswered for months unless there is another reason.
If It Takes Seconds
And then there are stories where the stars are, effectively, next door.
In Pandora’s Star and the rest of the Commonwealth series, wormholes connect distant worlds so efficiently that people commute between planets. Space itself ceases to matter. Interstellar civilization becomes one enormous, sprawling city.
At that point, the story is no longer really about distance at all. The stars are merely neighbourhoods.
This is not a criticism. It is simply a different kind of story.
Star Wars works because it treats the galaxy as though it were a fantasy kingdom. You can fly from one place to another in the time it takes to change scenes. Characters can arrive dramatically at the crucial moment because otherwise there would be no story.
The same is true of many space operas. Space is shrunk because readers want adventure, intrigue, romance and conflict between worlds. Those things require worlds to be close enough to interact.
The Conceit We Accept
FTL is one of the great conceits of science fiction: an impossible thing that almost every reader willingly accepts because it allows the story to happen. Without it, many science fiction stories would collapse under the sheer scale of the universe.
There would be no galactic empires. No interstellar trade. No rushing to save the colony world before it is destroyed. No fleet arriving at the last minute. No wandering starship visiting a different planet every week. Instead there would be silence, delay and loneliness.
And perhaps that is why so many readers underestimate the size of space. We are trained not to think about it. Science fiction, for perfectly understandable reasons, edits out the distances. It has to.
Otherwise, space is simply too big for the kinds of stories we most want to tell.
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