Rewriting a scifi story to fit with actual science, should I do it as I go, or just write first and make the needed changes while editing?

My world exists in my mind, clear and palpable. but I am somewhat...

Let's just say that when I read something I find annoying I usually don't finish the book, no matter how interesting everyone tells me it is.

I want my world to be as realistic as possible. It's a fantasy scifi world, but it doesn't mean it shouldn't follow the laws of physics.

So, as I come across a situation that causes me to doubt the reality of it, should I just keep on writing and worry about that when editing (maybe mark the place I need to work at), or research and deal with the needed changes now?


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    you can ask on worldbuilding with the "hard-science" tag to confront your scientifical credibility.
    – njzk2
    Oct 2, 2017 at 1:08
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    @njzk2 That depends on if it is FTL or not or even Science theory. Hard-science is mostly things that are within the realm of current science principles. However, if he wants to make something like instant teleportation believable, hard-science wouldn't help, however he can do a reality check with it to see if his method of explaining the tech is believable/plausible.
    – ggiaquin16
    Oct 2, 2017 at 15:23
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    It's planetary science. There's where my problem sits. My imagination shows me one thing but I've loved astronomy since I was a kid, have some small notions but not enough to know about what' actually possible, and that is my problem. I HATE reading ridiculos things so I don't want to write them. Oct 2, 2017 at 15:46
  • @shieldedtulip if you want to check your ideas, worldbuilding.se is definitely the place to go. In some cases, physics.se can be more accurate, too.
    – njzk2
    Oct 3, 2017 at 1:25
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    I also like good science in my fiction (and often feel disappointed on supposedly hard scifi novels). This leads to extensive research since, although having a background in R&D, I'm not an expert in the great majority of the fields I need to write about. Personally I do it by layers. Write the story first to the best of your scientific ability. Than list your research topics. Go to first and see if its compatible with first layer. If not rewrite as needed. Proceed to next topic and follow the same rules. Its a slow process but it will help you understand what is your tolerance for sci. rigor.
    – armatita
    Oct 3, 2017 at 12:42

5 Answers 5


The reason why some people like hard science in their science fiction (as opposed to the "science fantasy" you see in TV shows like Star Trek) is because in clever hard science fiction, the plot is derived from the science elements. The hard science is not just scenario dressing, it's what drives the plot. So when you write the story first and then insert the science later, you are wasting a lot of interesting plotpoints which can be derived from the constraints, possibilities and quirks of real-world science. But in a soft sci-fi story which focuses more on character interaction than on the science, this is just a secondary concern.

But there is also another risk: You might write a critical plotpoint and then after you wrote the whole story you realize that it simply can not be reconciled with the laws of physics. Then you have three options, and neither is really good:

  • Change that plotpoint, which means you are potentially throwing away half of your story.
  • Keep it in, knowing fully that it's a plothole. A reader might forgive it when your whole story is rather soft sci-fi, because in that case they wouldn't assume anything to follow the laws of physics. The reader might also forgive it when it would be a very minor detail you got wrong. But a critical plotpoint which is scientifically implausible in an otherwise scientifically accurate story? That will make it hard to suspend disbelieve.
  • Hang a lampshade on it. Acknowledge the break from reality by having characters attribute the plotpoint to some unknown sci-fi phenomenon they don't fully understand either. This, of course, might in some cases raise further question, like why the phenomenon and its implications aren't even more interesting to the characters than the actual plot it is trying to make work or if it wouldn't also affect other plotpoints.

To avoid these situations, do the reality check first, then write it down.

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    This is a good point. It illustrates that your approach will depend on your audience.
    – SFWriter
    Oct 2, 2017 at 18:47

Fix it now vs fix it later is a perennial question in writing. Often the answers given are absolutist one way or the other, or come down to "whatever works for you". But I would suggest a different approach, one which divides changes into structural and cosmetic.

If you were building a house and you discovered a crack in the foundation or a flaw in the wiring or the plumbing or a mistake in the interpretation of the blueprints, you would not go ahead with the drywall and plan to fix those faults later. They are all structural faults and to carry on without fixing them will be to make the cost of fixing them later much much greater.

On the other hand, if you find a crack in a pane of glass, or one of the appliances is delivered in the wrong colour, or one of the painters missed a spot, you would not call a halt to all construction activity while you waited for those issued to be fixed. They are cosmetic changes and a delay in fixing them will not affect the structure of the house overall, nor will fixing them later be significantly more expensive than fixing them now.

For a story to work, you have to get the structure right. If you realize that the structure is wrong, there is no point in continuing to build. You should fix the structure first before you continue.

If you are a beginning writer it is certain, and if you are experienced, still likely, that the cosmetic features of your story will not be great at the end of the first draft. You will have a lot of work to do to get the cosmetic aspects of your story right. But you probably should not stop to fix the cosmetic issues in chapter 1 before you move on to chapter 2. This is for two main reasons:

  1. You don't yet know if the structure of your story is sound. Until you are sure of that, you may just be taping and mudding walls that you are going to have to tear down anyway.

  2. Getting the structure right is probably served by working steadily through the arc of your story. That does not necessarily mean outlining the plot. Sometimes the arc is not in the plot but in the emotional or moral progress of the character which can only be worked out with significant narrative detail. But it does mean that you can press on with the main arc and leave any caulking and touch-up painting until later.

To apply these principles to your situation, you should ask yourself, is getting the science right a structural or cosmetic issue? If the story arc turns on some scientific detail that you decide you need to change, that might derail the plot going forward, requiring a complete rewrite. In that case, you would be well advised to fix it now. If the details are cosmetic, though, a kind of aesthetic treat or a form of reassurance or tribal signalling to your intended readership, you can safely leave them to afterwards and might be better off to continue with the development of the main story arc.

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    It's structural... important parts of the plot depend on getting it right or not. Thank you. Oct 1, 2017 at 17:53
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    What an excellent answer! Oct 3, 2017 at 19:32

Whose laws of physics...?

You're writing this world. If you can make it internally consistent, that's what matters. It doesn't have to follow our physics, so long as everything hangs together.

If the plot needs a certain thing to happen, then a certain thing happens. The rest of the world just has to catch up behind it, and you backfill to keep consistency. That's it. If later in the book you find the physics needs to work a certain way for a plot event to happen, then you may need to go back and rewrite earlier parts to prepare for that. So long as you haven't contradicted yourself, it doesn't really matter when you do it. If you do find you've contradicted yourself, you've either got to change something, or you've got to figure out how both cases are possible.

Consider The Martian as a prime example. Andy Weir took extraordinary steps to make sure everything about Mark Watney's survival was physically possible, and Watney takes us through his reasoning for how he's going to make things work. (And several times, working out how he managed to screw up and nearly kill himself, so he doesn't make the same mistake twice.) It demonstrated genuine seat-of-the-pants engineering and positive thinking, not just some A-Team/MacGuyver "we just happen to have all this stuff to hand" nonsense. He's also careful to contrast Watney's own opinion of himself (the least intelligent, least useful member of the crew) with Mission Control's assessment of him (a brilliant generalist and an absolute master of lateral thinking), which is a great bit of character writing. As a book, it works on the hard-sci-fi level, on the "thriller" level, and on the characterisation level. It even translated fairly well into a film.

However the event which traps Watney on Mars (a monster windstorm) is utterly impossible in the thin atmosphere of Mars. Winds can be fast, but there simply aren't enough molecules to apply any real force to anything. Weir was completely aware of that fact, but he needed it for the plot, so it happened. And having created a Mars with wind and dust storms, Weir ensures Watney is constantly tackling wind-blown dust, and has to deal with a second dust storm later in the book. So the book is completely internally consistent, and there is no suspension of disbelief required (unless you're a real hardcore Mars fan, of course!) because everything hangs together within the "Watneyverse".

  • It's possible to write a poem that is not 14 lines, but that's not useful advice for someone who wants to write a sonnet. When a writer sets out to write in the bounds of science, it's fine for the writer to look to keep in those constraints.
    – Mary
    Dec 31, 2022 at 21:12

I'm trying to make certain I have scientific details correct in my current project. I've been checking everything from solar radiation to rainfall patterns in different biomes. My storytelling will suffer if I get too hung up on the science, though, and i risk falling down the rabbit hole of scientific minutiae every time I start googling for what is known about something scientifically. But on the other hand I want no misinformation.

Many readers will shut off with too much science, in my experience. I think characters must come first.

I decided to write the first full draft focusing on story and characters. I added only what science I had on hand or could be found with a quick google. i flagged areas that could be beefed up with better science, in a subsequent draft.

I've spent some time on Worldbuilders SE to check my understanding of the science of key plot points.

I will devote one round of edits specifically to checking and correcting science.

I wanted to post an answer because I resonate with your question. What I settled on was to write the first draft to get it on paper, and then dedicate one edit to science. This is working for me.

(I've been surprised by how many people are turned off by science. Even a simple word like Helium made one reader uncomfortable this morning. Characters first.)

  • Guess it is true what is said, we can't expect others to expect what we expect... Not everyone loves science as some do (I love science) sadly. Thanks for sharing your thoughts. Oct 1, 2017 at 23:27
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    "Many readers will shut off with too much science"... Getting the physical underpinnings of your world right doesn't automatically mean you need to encumber your readers with it. Just as long as the story reflects the correct results where it's pertinent to the story and its characters. Readers who do like science will appreciate your efforts to get it right.
    – Martijn
    Oct 2, 2017 at 8:10
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    @shieldedtulip That isn't to say though you can't apply theoretical science and current principles. Star Trek does a great job of taking some really good theoretical science and principles and turning it into a show with the average watcher just thinking, oh hey that's cool a bunch of futuristic sounding science terms NEAT! But to a bigger science fan, it's all about the theories of tomorrow. Many of our current devices today are because of Star Trek fan nerds like tablets for example.
    – ggiaquin16
    Oct 2, 2017 at 15:19
  • @ggiaquin I do love all the neat stuff on Star Trek and Stargate I can say I watched every episode of all the series. But... planetary science is somewhat well defined 😟 Oct 2, 2017 at 15:50

I'd definitely try to get the rough structure down first as previously mentioned. After that, you could consider switching efforts depending on your motivation.

  • When you have the time and motivation to be detail-oriented, and to research the science behind part of the story, do so.
  • When you reach an impasse/run out of energy/get sick of that, you can set that aside and switch to moving forward with fleshing out the story outline or writing more of individual parts of the story.
  • When a concern or idea on either of these things pops up, write down enough details so you can revisit it later.

This would hopefully let you make progress along both lines, so when the story's mostly done, so will (hopefully) a good chunk of the science research. You may need to rework some of the story afterwards, but you're always making progress.

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