Another Monday morning, another Monday morning ramble. When I posted my last ramble, and described it as such, I'd no intention of it being a regular thing. But what the hell. At least calling it a "ramble" means I don't have to put forward a coherent argument. Or even make much sense.
And so, on that note...
Things work the way they do. And, in most cases, we know how that is. Not just physical laws, but society, politics, history, technology... An average reader is unlikely to be an expert in all these, but they know enough. So if, in a mainstream novel, the protagonist drives from London to Glasgow in an hour, we know the writer should go and check Google Maps again.
But in an sf novel, where the background consists chiefly of genre furniture and literary devices...
Much of the trappings of science fiction are convention, rather than any real attempt at constructing a scientifically rigorous future. (This is why sf is not prediction.) Stories set on galactic stages require an abundance of earth-like planets. Yes, exoplanets are more common than we had anticipated, but we've yet to find an habitable one. The worlds of the story exist because the story requires them. And, since our heroes need to travel from world to world to resolve the plot, some form of interstellar drive also becomes a necessity. It doesn't have to be real, it doesn't have to be based on real-world theorising - such as the Alcubierre Drive.
World-building is the art of choosing genre conventions which fit the story. And without which the story could not take place. That's the important bit - no convention(s), no story. If the plot still works without the genre trappings, it's not science fiction. It's a western in space. Or a WWII story in space. Or the Napoleonic Wars in space. Or...
A purist would claim you use only those genre conventions necessary for the plot. After all, the plot is the thing. But the rest of the background, that's chrome; that's the the bright shiny stuff the writer hopes will distinguish their novel from their rivals. That's what readers look for when they want immersion. They want the story's universe to give the appearance of life outside the story.
And this is where it gets difficult. The writer of a science fiction novel might well be an expert on the world of that novel. After all, they invented it. But that world has to convince on every level. The details have to be right. Earth needs to rotate the right way. No using parachutes to land on airless moons. No earthlike planets sailing gracefully through intergalactic space.
Conventions will only get you so far. And they only pass muster for the most part because they've been tested repeatedly during the past 80 years. Perhaps this is why such story mechanisms have changed little. Evolution is a slow process. Those which have survived the testing process have shown they work. They don't need fixing.
But using conventions makes a novel conventional.
And the good ones are anything but that.