Megastructures of Mercyblades
Mercyblades is a novel that blends space opera adventure with a hard sci-fi setting. It features many awesome megastructures you don’t often see in space opera. Who needs clever spin-gravity habitats when you have “gravity plates” in the floor?
I do, that’s who.
The physics of O’Neill Cylinders, Orbital Rings, and Matrioshka Brains have been better covered on Issac Arthur’s YouTube channel. If you enjoy this sort of thing, you really should head over there and subscribe. (Thanks, Isaac!)
What I’d like to discuss in this article are the narrative impacts of having these technologies in your setting. Who might use them and for what? What might it be like to live inside one? And how can you make them cool as hell in your own stories?
Let’s begin with bottle worlds…
Rotating Cylinder Habitats
When you can’t just conjure gravity all willy-nilly, you can simulate it with rotational motion. Just as water stays in a bucket when spun fast enough, people and objects inside a rotating habitat would be pressed against the inside wall. If you put a bunch of furniture on that wall, it becomes the floor and voila! Simulated gravity.
The bigger you make your habitat, the more it feels like real gravity, so O’Neill Cylinders (named after their inventor, physicist Gerard K. O’Neill) can get pretty big, multiple kilometers in diameter. That’s enough internal space for an entire city and, if you need more, just make it longer.
But none of that is why they’re so fun.
The closer you get to the center of a rotating cylinder, the lower the simulated gravity. You can have normal gravity on the “ground” floor of a building, low-g sports on the upper floors, and recreational zero-G flying along the central axis. Anyone hanging off the outside of an O’Neill cylinder would feel like they’re “falling” into space. (If you think that sounds like it’d make a cool fight scene, I’ve got a novel you might enjoy.)
In Mercyblades, these rotating habitats are called “bottle worlds,” because the people who build them want to seal themselves off from the rest of humanity and remake Creation in their own image. They control the climate; the day/night cycle; the temperature, weather, even the gravity. They get to design the buildings, the views, and the bird songs. In short, you decide how people live in your bottle world.
They’re also extremely private, completely self-contained and potentially light-minutes from their nearest neighbor. If you’re an aspiring cult leader or petty tyrant who doesn’t play well with others, an O’Neill cylinder offers the ultimate controlled environment. You can f — off into the far reaches of the solar system and do things your own way (until the Mercyblades show up to wreck your sh — , of course).
Let’s talk art direction. Mercyblades includes four very different bottle worlds, but two of them provide a really great contrast and, I think, illustrate the possibilities. The first is Osho’s Bottle, a pastel forest of cherry trees along a winding river, lit by a swarm of rainbow mirrors strung along its axis, casting everything in an otherworldly glow. Synthetic birds recharge their batteries while perching on tree branches from which pink and purple blossoms are always falling.
On the opposite extreme, there’s a corporate bottle world drenched in total darkness. Its inhabitants use an augmented reality system called “surreality” to see. Through that lens, their abyssal city glows with neon lights and enormous holograms, art written across the sky. It’s Blade Runner meets Burning Man, run by a dystopian mega-corporation.
Both of these worlds are built on the same technology, just different aesthetic preferences. And that’s entirely the point: When you build a bottle world, your aesthetic preferences become the world. It speaks to the kind of narcissism that would motivate a private individual to create something like this.
On the other end of that spectrum…
Orbital Rings
This is the hardest one to wrap your mind around, no pun intended. An orbital ring stretches all the way around a planet or moon, experiencing its gravity… but it never falls down. It just hangs in the sky, without any visible means of support, like f — ing magic!
Imagine putting a satellite in orbit. It keeps itself up with momentum alone, no magic required. Now, put a second satellite in orbit right behind it. Then another and another and another… until they form a spinning ring around the Earth. This is the backbone of your megastructure, but we’re not interested in zero-G living, so it’s useless by itself.
Next, we surround the spinning ring with a bunch of stationary magnets. These allow us to keep the ring spinning, which is great, but we can also hang things from them. Objects under magnetic levitation don’t transfer any angular momentum, so the ring itself spins while the magnets remain stationary. If you stood on top of one, you’d experience something like 90% of Earth’s surface gravity.
Presto! You have an orbital ring.
You can pile civilization on top of those levitating magnets all day long. To counter the weight, just spin the ring faster. You can even drop space elevators down to the surface. That makes orbital rings a great way to get people and cargo to and from orbit (way better than rocket launches), but I think simple economics make for boring motivations. Why else might people go to all this trouble?
An orbital ring is inextricably connected to the body is surrounds. It’s part of the world below, but apart from it. That makes it a great choice for planets being reclaimed from war or environmental collapse. It’s even better for maintaining quarantine over an alien infestation, deadly virus, virulent AI, or the dreaded gray goo. It might also make sense during a long terraforming project, when the surface is not yet habitable.
Thematically, an orbital ring looks down on the world below. The people who build them are putting themselves in a superior position, whether as oppressive masters of concerned custodians. In Mercyblades, Earthring is inhabited by people who want to restore the Earth after a long period of decline. They hang their homes from the bottom of the ring, so they can gaze ever downward at the pale, blue dot.
Matrioshka Brains
You know what? Forget about gravity, forget about life support, let’s just live as disembodied brains plugged into a satellite in deep space. A Matrioshka Brain, named after those famous Russian nesting dolls, is the ultimate in breakaway civilizations. Its inhabitants are simulated minds running on an ultra-efficient, ultra-cold network, dreaming virtual realities into existence at the speed of thought.
Faster than thought, if you’re doing it right.
Computers run faster at low temperatures and, when you’re a simulated brain, that determines your subjective experience of time. Overclock and subjective time runs much faster. That means you get to have many times more experiences, live many more lives, than you could in baseline reality.
A single Matrioshka Brain could support countless virtual worlds. Every inhabitant becomes a godlike storyteller, for others or themselves alone. They can do or be absolutely anything, create environments that defy the laws of physics, simulate any time or place. Virtual realities. You get it.
I say they’re the ultimate in breakaway civilization, because they’re just as self-contained as the most paranoia-fueled O’Neill Cylinder, but contain infinite living space. They’re bigger on the inside. If they’re overclocked, those inside will diverge from their parent civilization even faster. They’ll become aliens in no time.
In Mercyblades, they’re called dreamworlds, because virtual reality operates on dream logic. No menus, no heads-up displays, no video game UI conventions. Transitions between virtual realities are sudden and instinctual. To do it, just think it. I tried to fill them with the absurd, like a cottagecore reality where well-dressed minotaurs serve hors d’oeuvres on well-kept lawn. There’s a gingerbread village on the kitchen table and you can live there, too, if you want.
Dreamworlds are also home to the security-minded, some might called them paranoid. Criminals, malcontents, revolutionaries, real breakaway civilization material. Because they’re so remote, and so overclocked, anyone trying to break in from afar is at a sever disadvantage. There’s no faster-than-light anything in Mercyblades, so light lag to a Matrioshka Brain is a real killer. If you want to snoop, you have to schlep all the way out there in person.
Recap
Sci-fi megastructures offer writers more than just interesting physics. They say something about the people who build and live inside them. Give that some thought, next time you’re looking for something more interesting than another alien biome with a single city on it. Specifically…
Use O’Neill Cylinders for self-contained “bottle” worlds. They spin to simulate gravity and are perfect for paranoid egomaniacs.
Orbital Rings surround a planet or moon, hanging in the sky by sheer momentum. They are part of the world, but apart from it, perfect for overlords or prison guards.
For breakaway civilizations, consider a Matrioshka Brain. They’re bigger on the inside, contain infinite virtual worlds, and can make time flow faster by overclocking.
And there are so many other interesting megastructures out there, from spinning dome cities to shell worlds around black holes. Check out this handy compendium video for a crash course.
And check out Mercyblades for all the above, plus a bottle world called The Wilderness. It’s an artificial wildlife preserve for big game hunters. Think Westworld meets Jurassic Park… with predictable results.
