## Interstellar MAD * Author: u/None * * URL: https://www.reddit.com/r/rational/comments/2vnibz/interstellar_mad/ * Score: 13 * Created: 2015-02-12T14:16:43 ### Post: Interstellar genocide is much easier than interstellar travel. Even ignoring life support technology and all the other fancy stuff, it only takes half as much energy - you can use the other guy's planet to slow you down. A rock traveling at 1% of light speed is basically an invisible, unstoppable super weapon. WMD doesn't really do it justice, it's more like a doomsday device. Say we make radio contact with some aliens from Alpha Centauri tomorrow. The very first thing we should do is embark on a crash program to build an orion drive, point it at their system and light it off. Yeah, it would take a few centuries to get there but a lot can happen in that time frame. It would be like a dead man's switch - we could call it off at any time by simply telling it to miss, but if something ever happened to humanity... well, we have insurance. I'm envisioning a steady stream of super weapons flying between the star systems of any species who know where somebody else's homeworld is. But I really don't know much about game theory. It would appreciate it if somebody who did could tell me how likely this scenario is. Also, can anybody think of an effective defense against a weapon like this? ### Comments: > **u/Izeinwinter** [+16] (an hour later) > > Given equal-tech societies, MAD works far better over interstellar distances than it does on a planet. The main thing you need for MAD to work is the assurance that any attack you launch will result in in a counterstrike which you can't stop. Most Interstellar weapons are detectable *years* in advance of any strike landing, no launch can be concealed because there is no stealth in space, and as long as you live on planets, you can't avoid incoming fire.. at all. Avenge it, yes. Dodge? No. > > So, basically, either there is an iron-clad balance of peace or everyone has abandoned planets all together and are living entirely in habitats that don't have predictable trajectories centuries down the line. > > Of course, equal-tech conflicts are exceedingly unlikely. > > The most likely shape of any actual conflict goes like this: > > Elder Society. "Behave or else" > Younger (and very stupid) society: "No". > > *Explosive device buried in the crust of younger society's home planet back when they were still figuring out this fire thing*: "Boom". > > War over. >> **u/None** [+3] (2 hours later) >> >> I think it's perfectly reasonable to consider two equal tech societies in this scenario. Just replace alien civilization with a human colony. After all, we don't actually know if aliens exist but we do know how humans think. >> >> It might be that the singularity never happens because any self-improving AI we invent just immediately fucks off into hyperspace or whatever and ignores us... I mean pretty much by definition we can't predict what it's gonna do. >> >> I know this is a ridiculous scenario I'm talking about but we're just having fun here. > **u/alexanderwales** [+9] *Time flies like an arrow* (2 hours later) > > If you can see the incoming superweapon, there's a decent chance it's possible to knock it off course. Intelligent species should also object to interstellar MAD because of the chance of catastrophic failures - if someone sends a superweapon towards you and says that they'll revoke it later, you're depending on them to stick around for centuries, through revolutions and upheavals. It seems very likely that when the time to revoke the attack comes around, the people who made the code are all dead and the superweapon has mostly been forgotten. > > A secondary defense is proliferation to the extent that it's not feasible to destroy the civilization like that. > > If you have interest, there's a book by Charles Stross called [*Iron Sunrise*](http://www.amazon.com/Iron-Sunrise-Singularity-Charles-Stross/dp/0441012965) which revolves around this idea - a planet is destroyed, and their dead-man's switch activates. The plot then revolves around attempting to revoke the retaliatory attack from completing. (This is the sequel to *[Singularity Sky](http://www.amazon.com/gp/product/0441011799)*, which is also worth a read, and should probably be read first.) >> **u/None** [+2] (2 hours later) >> >> The only realistic defense I can think of against an attack like this is a super accurate, super long range, super powerful laser. The projectile is moving way too fast for anything else to work. And if it's programmed to take random evasive maneuvers as it approaches the planet, it might be impossible to knock it off course before it's too late. Maybe you could vaporize the thing just before it hits to soften the blow or something, but I really don't know how the physics would work out... >> >> I think that in our own history, pretty much everybody objected to MAD, even the participants. Of course that didn't stop it from happening. Imagine the Ewoks in Alpha Centauri launch one of these super weapons at us. Well, what's the best way to insure that they don't forget about it a few centuries later? Launch one of our own right back at them. >> >> Even when we have millions of people in colonies throughout the solar system, the vast majority of humanity will still be living on Earth. I think it's reasonable to assume we could have orion drives or antimatter engines long before the population of humans living off world outnumbers those on Earth. A weapon like this might not make us go extinct but it sure could make us endangered. >> >> Thanks for the book recommendation, I'll definitely check it out. I know Stross is a good author but I haven't read much of his stuff. I'm reading Harry Harrison's *Stainless Steel Rat* series right now. It's classic sci fi adventure, and it's hilarious. >>> **u/eaglejarl** [+3] (4 hours later) >>> >>> > laser >>> >>> Good idea -- if you point your laser at the edge of the thing you are both reducing its solid mass and putting sideways thrust on it as the material sublimates. >>> >>> > Even when we have millions of people in colonies throughout the solar system, the vast majority of humanity will still be living on Earth. >>> >>> In the short term (a few decades, a couple of centuries) this will certainly be true, but a few centuries / millenia after we first leave Earth, I would expect it to be a backwater. There are more colonies with collectively more resources, and colonies are likely to have higher birthrates. >>> >>> > Harry Harrison's Stainless Steel Rat series >>> >>> Great series. The feel of it gets different in the later books as he gets older, but it remains a lot of fun. >>>> **u/None** [+1] (6 hours later) >>>> >>>> Yeah the laser thing is actually an idea bouncing around right now as a way to redirect asteroids. Turns out its a surprisingly efficient way to do it, though there might be problems with the vaporized material blocking or diffusing the beam. Another popular proposal is to fly a spacecraft close to the target asteroid and use the tiny gravitational pull between them to gently nudge it off course. >>>> >>>> Slippery Jim is my hero. I love these books. >>>>> **u/eaglejarl** [+2] (7 hours later) >>>>> >>>>> > fly a spacecraft close to the target asteroid and use the tiny gravitational pull between them to gently nudge it off course. >>>>> >>>>> That is totally full of awesome. >>> **u/Bowbreaker** [+1] *Solitary Locust* (a day later) >>> >>> Why not just send a similar device on a crash course with the opposing MAD? It's just a kinetic force weapon after all. >>> **u/iemfi** [+1] (a day later) >>> >>> Well couldn't you see it coming, shoot another orion style ship to intercept it, and then turn around and match speeds with it and intercept it, or just have a laser or something to kill the guidance and put it off course. It would take a lot more energy but if you're high tech enough to see it coming it shouldn't be an issue. Then now the planet which launched the weapon is screwed. > **u/None** [+4] (19 hours later) > > It depends on other species having the same loss-aversion as we do, else they'll be willing to trade off losing a larger amount of planets just to get at us than we are to get at them. > > OR we could just deem it reasonable for most civilizations capable of interstellar war to live at peace, and possibly even *trade*, rather than everyone desperately trying to work out the highly involved game-theory maths of whether they can "win" a MAD scenario and how much they're willing to sacrifice. > > OR, presuming sufficiently high-level technology, you can just redundantly back yourselves up using the local asteroid belt as substrate, since it's really much harder to chuck relativistic rocks at an asteroid belt. > **u/symmetry81** [+3] (3 hours later) > > This is essentially what the book *The Killing Star* was about. The moral of the story was that young civilizations shouldn't go around blasting radio waves into space until they've gotten sufficient second strike capabilities and know where all their neighbors are. >> **u/None** [+1] (5 hours later) >> >> Holy crap! Talk about relevant. Every time I think I have a new idea haha. I'm definitely putting that book on my list. >> >> Fermi Paradox: answered. Thanks for the recommendation. > **u/Someone-Else-Else** [+3] *Anti-Spiral* (4 hours later) > > This doesn't sound like the best idea. > > Let's assume that you make radio contact with aliens, and then realize that they've launched a rock at you at .01c. Do you assume that they're preparing MAD? Or do you assume that they're trying to kill you immediately. > > Let's assume they tell you they're preparing a MAD scenario. Not knowing their psychology, do you assume they're telling the truth, or lying? > > Let's assume you know their psychology and they're telling the truth. Do you trust that they won't go power-mad at some point, that they don't have any biases making your death more likely, and that they're likely to keep the code to destroy the WMD safe? In short, do you trust a group of aliens several light-years away to keep your planet safe when not doing so will not harm them (as they're likely dead or off-planet when your retaliation arrives)? > > Let's assume you trust them, but want to be sure. Do you stay on planet, or settle around the solar system? If you settle around the solar system, and they know you will, how can you assume that they've just sent a rock instead of self-replicating probes optimized for destroying your solar system? They've already shown that they're willing to destroy your civilization if they need to, and you might be considered a threat. > **u/duffmancd** [+1] (4 days later) > > The problem with MAD is in black swan events. The chance of a black swan turning out to be deadly (when considering armed, planet killing missiles) is much higher than it being beneficial. So you have a small tail with hugely negative consequences, over time something is bound to come up. > > I maintain that the only reason we're still here with the world's current armament is the anthropic principal. Think of the cuban missile crisis, the Norwegian rocket incident or the thought that any "rogue state" can cause the end of the world. (There was a comic linked on this sub a while back about this but I don't remember the name). When you're talking about interstellar distances, and hence times, the problem becomes worse. > **u/Newfur** [+0] *Crazy like a fox. Literally.* (4 days later) > > Say it with me again - wars that play with existential catastrophe and which are even vaguely symmetrical ARE NOT WINNABLE. Not at all. Not even slightly. Not even in terms of second-strike capability. You can't win if you're dead and everything you ever knew is now glassed. The best you can do is retaliation, and it is WILDLY IRRESPONSIBLE to promote that this is a good idea in any way. It is at best the least bad idea, instantiates Moloch, and allows people a feeling of smug superiority which isn't even slightly warranted. ---