I’m sitting here on October 15th with half a dozen files open on my computer, calculator at the ready, and a page of scratched calculations. I’ve been world building again.
In full disclosure, my last math class was college calculus and I don’t remember much of that. I’m no astrophysicist. I know that because I bought a book on orbital mechanics in hopes of cribbing a few formulas to use in my writing. It didn’t take long to realize that I was out of my element.
My primary source of world building math has always been How to Build a Planet by Poul Anderson. I have kept a xerox copy on hand since I first used it while writing Jandrax back in the seventies of last century/millenium.
Don’t bother to google it. There are so many resources available for world building on the internet today that it gets pushed to a back page. I don’t use the new stuff myself; it looks like a black hole you could fall into and never escape. World building can easily eat up all the time available for writing. Besides, there is a limit to the accuracy we need.
When I set up the solar system around Sirius, a long time ago, I popped in a few inner planets, more or less following Bode’s discredited law, and set their distances after calculating i, luminosity, for the most important planet.
Sirius A, for the record, has about twice Sol’s mass and produces about 23 times its radiation. I calculated the distances from it to where there would be a luminosity of 75% of Earth’s, 100% of Earth’s, and 125% of Earth’s, then dropped Stormking into the middle of that range. That gave me an orbit roughly the equivalent of Jupiter’s, so I took the length of Jupiter’s year and called that the length of Stormking’s year.
That was good enough for then, but not now that I’m actually writing. I have political exiles on Stormking (which has a Uranian tilt) who have to walk for their lives, continuously, to stay in the middle of that planet’s temperature extremes. I have to know the real length of the year on a planet that distance from Sirius, to see how far I have to make them walk.
The exiles have to proceed southward for most of a half a year, rest for a few weeks, then turn north again, forever. It provides all kinds of plot possibilities, but I owe it to the reader to get my figures straight.
Sirius is a double star, and that other star provides complications I can only approximate. Since I began seriously contemplating returning to Dreamsinger, I came to realize that the perihelion of Sirius B would, on some orbits, coincide with Stormking’s position on its orbit in a way that would cause a superheated event. Big trouble for the exiles; great opportunities for the puppet master. (That would be me.) I can’t calculate how often this will happen or how severe it will be, given my skills, so that will be a hole in my accuracy.
I moved the orbit of Stormking out to the 75% luminosity distance of 828 million kilometers to make my exiles slightly more likely to survive, and calculated the year length (in Earth days) from that, using formulae I don’t totally understand, and came up with 4493 Earth days. That is fairly close to my ballpark estimate of 4335, which is Jupiter’s year in Earth days.
Why do all this? Partly it is because you have to consider your audience. If you try to write hard science fiction, set around known stars, a few of your readers will be scientists, and a much larger number will be people who wanted to be scientists, or at least love science. You have an obligation to them not to do something dumb.
Actually, a lot of science fiction writers are scientists or engineers, and can easily do the math I struggle with. I admire them, but I don’t feel inferior to them. I got here by a different route and I know things they don’t know. In all likelihood, you know things I don’t know. It all comes out even in the end, or at least even enough that we can all share the same fraternity of people who enjoy science fiction.
Careful world building is a rule of the game. You wouldn’t play chess with two white queens. You wouldn’t write a western where Wyatt Earp carries a luger instead of a Buntline special. You might, however, give Earp a luger if you were writing steampunk. Different games, different rules. If you take the science out of hard science fiction, all you have left is . . . basically nothing.
Nevertheless, there are limits. I am not good enough at calculating orbits to know for certain what Sirius B would do to my scenario, but I know what has to happen in the story, and by God that’s what is going to happen, no matter what physics says. You have to draw the line somewhere.
Now it you will excuse me, I have three other planets to calculate, so my people can follow reasonable orbits traveling between them. I wouldn’t want to embarrass myself.
You know, sometimes I do miss warp drive. Punch a button, and there you are at Vulcan. It would be so easy.