The thing that we’re running from is the Bubble War.
It’s a truism that every new technological advancement in human history has been applied first to advance the interests of the horny. The printing press? Some Bibles, mostly porn. Antibiotics? Perfect for treating STIs. The ocular? Don’t get me started on what those were first used for. Large-scale antimatter production didn’t really fit that model, though. There’s nothing remotely sexy about a rapidly expanding cloud of high-speed quarks and gluons.
The second area where every new technology is applied, of course, is war.
In that space, antimatter worked out heinously well.
In fairness, our ancestors did spend about ten seconds or so thinking about how antimatter could be used for things like energy production and starship propulsion before they turned their attention to the ways it could be used to convert their fellow humans into radioactive dust. I’m guessing, though, that the main reason for that was that until the invention of the magnetic monopole bubble, there wasn’t any practical way to use antimatter as a tool of genocide. You can’t just make an antimatter bomb the way you can a thermonuclear bomb, for example. You need a way to keep your antimatter core completely isolated from any interaction with normal matter until you want it to do its thing, and absent a five-thousand-kilo magnetic torus and a vacuum chamber to keep it in, that’s pretty difficult to do.
The magnetic monopole bubble solved that problem neatly. As Jemma explained it to me, each one is a kind of knot in space-time, with the interior and exterior essentially existing in separate universes. Wrap a little dollop of antimatter up in one of those, and you’ve got a whole lot of potential energy stored in a compact and relatively safe-to-handle package. That’s how the Drakkar stored her fuel. When she was under acceleration, a steady stream of monopole bubbles filled with antimatter were passed through from containment into the reaction chamber, where they were mixed with opposite-polarity bubbles filled with normal matter.
Then, two by two, the bubbles popped. Annihilation occurred, and off we went.
You can probably see where this is going.
The bubble bomb is a very simple thing. You just pack a bunch of monopole bubbles full of antimatter into some kind of delivery device. When that device bursts over the target, the bubbles drift with the wind, forced apart from one another by their mutual magnetic repulsion. After a fixed amount of time, they pop.
Depending on how much dispersion you’ve allowed and what specific type of antimatter you’ve packed into your bubble, the result can range from an explosion that blows a hole through the stratosphere, to a rain of hard radiation and quantum particles that kills every living thing in the target area down to the viral level, but leaves the buildings and other infrastructure completely intact.
It was that bit that caught the attention of old Earth war planners. They’d had thermonuclear weapons for a long while by then, but they hadn’t figured out a way to make them useful for anything other than an apocalyptic suicide pact. The problem was that if you ever used enough of them to deliver a knockout blow, the environmental blowback in terms of fallout, garbage thrown into the stratosphere, lingering background radiation, etc., etc., meant that you’d wind up killing not just your target, but also their neighbors, their neighbors’ neighbors, their neighbors’ neighbors’ neighbors, and so on back to probably yourself—and that’s assuming that your victims didn’t have their own doomsday arsenal to throw back at you, which they probably did if you were contemplating that kind of escalation against them in the first place.
The bubble bomb solved all of those problems. Structured and deployed correctly, it allowed you to sterilize wide swaths of your enemy’s landmass with almost no lingering side effects. You could make the bombs small and light and deliver them stealthily enough that the enemy wouldn’t know they were coming until they were already dead. You could kill everyone and everything, and then move right in and take over the next day if you wanted to. You didn’t even need to worry about the bodies stinking, because there wouldn’t be any viable bacteria around to make them decay. From a warfighter’s perspective, it was the perfect weapon.
From an actual human being’s perspective, of course, it was a nightmare.
The critical context here is that old Earth was undergoing a bit of an environmental crisis at the time that all this was going on. Their population density was almost a hundred times greater than Eden’s is now, which is more like a thousand times the average density of most of the Diaspora, and their industry and agriculture were a lot more inefficient and messy than ours are. As a result, they were basically choking on their own waste. Over the course of a few hundred years they’d altered their atmospheric chemistry to the point that whole chunks of the planet that were once heavily populated were rapidly becoming uninhabitable, and they were having serious issues with distribution of both food and water. Combine this with the fact that they were also completely fractured politically—there were nearly two hundred independent political entities claiming sovereign rights over one part of the planet or another—and then throw in the sudden appearance of a weapon that allowed one of those entities to eliminate the population of another completely, and subsequently to move into their newly empty territory, and you’ve obviously got the makings of a very bad situation.
Records of the Bubble War are probably not particularly reliable, since they were almost entirely written by the folks who struck first and hardest and therefore survived, but there are a few things that we know for certain. The war lasted, in total, less than three weeks. Only a half dozen or so of those independent political entities participated. It ended only when the planet’s existent supply of antimatter was exhausted.
Most importantly, it left more than half of old Earth’s population, which at the time was all there was of us, dead or dying.
Most historians think that the launch of the Ching Shih, which took place less than twenty years later, was a direct reaction to the Bubble War. What else could explain the Diaspora? What else could explain the fact that we left the one planet in all of creation that we were actually evolved to inhabit, the one that didn’t require any terraforming or inoculations or wars with native sentients, for … well, for places like Niflheim? It was clear to those people that if humanity stayed in one place, we’d eventually kill one another—and they were almost certainly right. Nobody has heard a peep out of old Earth in over six hundred years.