Message in a Bottle Planetary Calculations

So, for those of you who haven’t read the July 8th chapter of Message in a Bottle (G5.05: Satelite), probably go and read that before going on. Either these things aren’t going to make sense to you, or they’re going to be a major spoiler for that story. So seriously, go read that, then come back here. We good? Good.

So I am not a numbers pony. I can handle some basic calculations, but nothing like what would be required to make sure the megastructure I wanted for Message in a Bottle would work according to known laws of physics (though not necessarily using any known materials). I have a very particular image for what I wanted for the Equestrian homeworld.

Enormous thanks to my friend Star Scraper for his help with all the nitty-gritty math. Hopefully, if you have any questions about what I’m about to show you, he can answer them, because I can’t.

It’s very important to me to have a story that’s as plausible as possible, even given the remarkable things depicted in Message.

So first, a brief word about scale.

This image is more for understanding than actual proportions. The true width of the ring is closer to this:

Because gravity is a product of rotation, it varies as we approach the edges of the ring. If you want some idea of the scale of that variability, it’s something like this:

The mathematics used to reach these numbers are entirely beyond me, but for those of you who like to get real deep into the math, I’ve got the link to all the calculations for you to check them out. That’s an album, by the way, not one page.

The narrative isn’t going to be about any of these numbers… but I wanted to give those readers who do care a snapshot of the lengths we’ve gone to in order to make sure the physics of the story make sense.