The imperative of ending SETI Now

[SpaceMarine93]

Granted, everyone nowadays, even people who don't know much about science, wanted to meet aliens. This is an instinct which everyone is born with - the desire to meet someone else and stave of loneliness. Over the last few centuries many pieces of fiction have been conjured postulating what these visitors from the stars would look like and behave. Inevitably people would start searching for them, as is the purpose of SETI.

In my point of view, this is possibly one of the biggest mistakes we could make.

The reason for this could be seen on a rather well known science fiction website, ATOMIC ROCKETS. The following is an excript of the three main viewpoints:

"The Optimists, whose patron saints were Drake and Sagan, believed in a universe crawling with gentle intelligence — spiritual brethren vaster and more enlightened than we, a great galactic siblinghood into whose ranks we would someday ascend. Surely, said the Optimists, space travel implies enlightenment, for it requires the control of great destructive energies. Any race which can't rise above its own brutal instincts will wipe itself out long before it learns to bridge the interstellar gulf.

Across from the Optimists sat the Pessimists, who genuflected before graven images of Saint Fermi and a host of lesser lightweights. The Pessimists envisioned a lonely universe full of dead rocks and prokaryotic slime. The odds are just too low, they insisted. Too many rogues, too much radiation, too much eccentricity in too many orbits. It is a surpassing miracle that even one Earth exists; to hope for many is to abandon reason and embrace religious mania. After all, the universe is fourteen billion years old: if the galaxy were alive with intelligence, wouldn't it be here by now?"

What got me absolutely worrying is the third point of view:

"Equidistant to the other two tribes sat the Historians. They didn't have too many thoughts on the probable prevalence of intelligent, spacefaring extraterrestrials — but if there are any, they said, they're not just going to be smart. They're going to be mean.

It might seem almost too obvious a conclusion. What is Human history, if not an on going succession of greater technologies grinding lesser ones beneath their boots? But the subject wasn't merely Human history, or the unfair advantage that tools gave to any given side; the oppressed snatch up advanced weaponry as readily as the oppressor, given half a chance. No, the real issue was how those tools got there in the first place. The real issue was what tools are for.

To the Historians, tools existed for only one reason: to force the universe into unnatural shapes. They treated nature as an enemy, they were by definition a rebellion against the way things were. Technology is a stunted thing in benign environments, it never thrived in any culture gripped by belief in natural harmony. Why invent fusion reactors if your climate is comfortable, if your food is abundant? Why build fortresses if you have no enemies? Why force change upon a world which poses no threat?

Human civilization had a lot of branches, not so long ago. Even into the twenty-first century, a few isolated tribes had barely developed stone tools. Some settled down with agriculture. Others weren't content until they had ended nature itself, still others until they'd built cities in space. We all rested eventually, though. Each new technology trampled lesser ones, climbed to some complacent asymptote, and stopped — until my own mother packed herself away like a larva in honeycomb, softened by machinery, robbed of incentive by her own contentment. (ed note: Read the book for that bit to make sense)

But history never said that everyone had to stop where we did. It only suggested that those who had stopped no longer struggled for existence. There could be other, more hellish worlds where the best Human technology would crumble, where the environment was still the enemy, where the only survivors were those who fought back with sharper tools and stronger empires. The threats contained in those environments would not be simple ones. Harsh weather and natural disasters either kill you or they don't, and once conquered — or adapted to — they lose their relevance. No, the only environmental factors that continued to matter were those that fought back, that countered new strategies with newer ones, that forced their enemies to scale ever-greater heights just to stay alive.

Ultimately, the only enemy that mattered was an intelligent one.

And if the best toys do end up in the hands of those who've never forgotten that life itself is an act of war against intelligent opponents, what does that say about a race whose machines travel between the stars?"

When we think about it, the historian argument makes absolutely perfect sense: Human history had always been a dominant and superior power trampling weaker ones under its boots. Europe persecuted the Aztecs, Mayans and Incans of Americas back in the 1500s - 1700s. Americans massacred the Native Americans in the 1800s - 1900s. The UK colonized India throughout the 1800s, Various western powers bullying China in the late Qing Dynasty, the Nazis dehumanizing and genociding anyone who doesn't fit their racial category and can't fight back, Americans dehumanizing their Vietnamese enemies back in the Vietnam War etc.

And let us not forget how humanity always hunt and exterminate other species of lower lifeforms for various reasons, good bad or otherwise.

Frankly, the chances are if aliens more advance than us ever found out about us, we are practically screwed

So I propose that we end any attempt to attract extraterrestrial life forms in the future. Any objections?

[K. A. Pital]

Yeah, projecting your apish psychology on a higher intellect is definetely sensible. However, if you look at current society, you'd find that criminals and especially violent criminals usually are intellectualy underdeveloped. If we assume that there's a correlation, but not a causation, we'd have to find the same level of violence among the higher educated portions of society. However, that does not happen.

Technically, the postulate of benevolence would assume that a species that is so advanced that humans are not a threat to it, would not bother with doing the humans any harm, except inadvertedly. Consider the human-ant analogy. Humans don't start a xenocide of the ants, because the ants are not a threat. They can kill them inadvertedly by stepping on them or kill them to clean out their garden, which is a bit more scary. However, none of the above demonstrates any malevolence.

Humans love to project their malevolence, which is usually directed at their own species for an obvious reason: a human is always a threat to a human. It's nothing but a case of massively useless self-projection.

[fgalkin]

Except for those children who set anthills on fire for fun. We just might run into space skinheads or something. A minor group, but enough to kill us dead.

EDIT: Spacemarine, SETI is dedicated to searching and analyzing signals with the hope of finding a pattern that denotes intelligence. To "hide" from the aliens, we would need to shut down all radio transmissions, essentially going back to the 19th century.

Have a very nice day.
-fgalkin

[Formless]

OT the OP: You are a retard on so many levels. Haven't you ever heard of passive SETI? You want to shut down a project that hasn't even started yet in earnest that does not have to leave any trace of our existence (unless of course we choose to do active SETI) based on the potential existence of Space Conquistadors. Let that sit in for a moment. You want to shut down something that hasn't even started, that wouldn't in any way require us to give away our position, so that you can essentially scare away imaginary tigers.

I'll go into more detail in a moment, but in the meantime let this sink in. You don't even know what the fuck SETI is. That is how much you've jumped the gun with your argument.

Search for Extra Terrestrial Intelligence. Key word is SEARCH.

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Moment over.

We've been over this a million times. If you think interstellar war with aliens is going to ever be a realistic danger, you have been reading too much goddamn space opera. Ignoring all the arguments about the Fermi Paradox and whether or not a violent civilization will survive the discovery of such things as nuclear weapons, the distances are too vast and the resources are too numerous to really be fought over. Barring enemies that are batshit insane and/or robotic hordes of von neuman machines out to turn the universe into uniform factories that make more von neuman machines, the likelihood of alien beings being an existential threat are nill. You can't fight the laws of physics.

Atomic Rockets exists to inform people who wish to write (hard) sci-fi. It is not there to actually take a side on this kind of debate, so it only serves to tell you what the arguments are, not what is the most likely future of humanity. If Nyrath wanted to do that, I'm betting he would be writing sci-fi rather than making a site to inform potential sci-fi authors. The rest is up to the author based primarily on what makes a good story.

One thing that AR leaves out is that most SETI advocates such as Sagan believed that the most likely form first contact would take would be radio transmissions, not the exchange of spacecraft and certainly not armed warships filled with Space Conquistadors. Hell, you can read Sagan's book called... um... Contact. Or watch the movie. Its seriously good.

Also, another aspect that AR leaves out is the anthropocentric fallacy of the argument-- that aliens think like us and want the same things we do. Biologically speaking, there may be little in common with them and us. They may look at our world as toxic, to be left alone to its native inhabitants. Need a historical precedent? Goddamn snake Island. I am dead serious. There are places on our own planet that no sane human being would set foot on precisely because of what lives there. Need a fictional analogue? War of the Worlds. Though its less "viruses" and more "bacteria and fungi" that would be the undoing of real martians. The idea is the same.

You also cannot have this discussion without going over the cost benefit analysis. What are the benefits of discovering a new civilization? Well, for starters, the very discovery would be valuable for its scientific, philosophic, and theological ramifications. If we get into communication with another civilization, who knows what knowledge they might exchange with us? Cultural exchanges can be beneficial as well as dangerous. What would you say if the first thing that aliens told us was how to build wormholes in a convenient and relatively cost efficient manner? The exact value of the exchange will only be known after the fact, but it could be invaluable for all we know.

Lastly, just in case you think appeals to history are the end of the discussion, I point you to the last chapter/episode of Sagan's book/series Cosmos ("Who Speaks for Earth?") where he compared and contrasted the Conquistadors with the Lapérouse expedition. Suffice to say, Conquistadors get all the press and perhaps for good reason, but not all first contacts between civilizations end in a bloodbath.

[K. A. Pital]

You always have such a chance.

It pays to note that the more advanced First World nations become, the less murderous they were in their colonization efforts. Mongol conquests were incredibly brutal; colonization of America annihilated the natives. However, the late-XIX and early XX century discoveries and colonizations were not as brutal as that.

If we go further, we'd find that sufficiently advanced economies actually benefitted from decolonization, and thus a hypothetical Kardashev III or Kardashev II civilization wouldn't even need anything from Earth or Solar system par se. And if you don't need anything from them, there is no rational reason to attack them or harm them.

Only irrational reasons are left. But irrationality decreases as the level of advancement increases; it is more or less a common trend. People pray less to magical pixies, they start building cause-and-effect constructs to explain their actions. So the probability of meeting "space kids" or "space skinheads", i.e. an extremely technologically advanced, but culturally primitive civilization is actually getting smaller and smaller as the potential aliens get more and more advanced.

The worst part, of course, if there is a physical principle that allows Kardashev 0,5-1 civilizations to have some sort of interstellar travel method. In this case we can project our own civilization as the nearest approximation and expect agression with a high probability.

[fgalkin]

One does not need to send spaceships to destroy one's enemies. A single rocket travelling under relativistic velocities would be undetectable until close by, uninterceptable, and exceedingly lethal to any planet it crashes into.

EDIT: Stas, really? Need I remind you of the Congo Free State and the Philippines (early 20th century), Japan's Asian conquests or French colonial wars?


Have a very nice day.
-fgalkin

[K. A. Pital]

Except RKVs are extremely hard to accelerate to the speed necessary for the projectile to become uninerceptable. The speeds are over 0,5c. This is out of our technical capability. So we can safely assume other Kardashev 0,5-1 aren't capable of it either.

[Guardsman Bass]

Except RKVs are extremely hard to accelerate to the speed necessary for the projectile to become uninerceptable. The speeds are over 0,5c. This is out of our technical capability. So we can safely assume other Kardashev 0,5-1 aren't capable of it either.

Targeting would probably be a bitch at interstellar distances too, unless you crept right next door to the targeted civilization.

On the OP, we had a good discussion of this exact topic a while back. The general consensus was that shooting at an alien civilization is probably bad news, because you don't know exactly who you're shooting at. What if they're much more powerful and extensive than you?

[SpaceMarine93]

"Technically, the postulate of benevolence would assume that a species that is so advanced that humans are not a threat to it, would not bother with doing the humans any harm, except inadvertedly. Consider the human-ant analogy. Humans don't start a xenocide of the ants, because the ants are not a threat. They can kill them inadvertedly by stepping on them or kill them to clean out their garden, which is a bit more scary. However, none of the above demonstrates any malevolence."

True, quite true. If you want a better analogy, read the Complete works o HP Lovecraft.

[SpaceMarine93]

"Lastly, just in case you think appeals to history are the end of the discussion, I point you to the last chapter/episode of Sagan's book/series Cosmos ("Who Speaks for Earth?") where he compared and contrasted the Conquistadors with the Lapérouse expedition. Suffice to say, Conquistadors get all the press and perhaps for good reason, but not all first contacts between civilizations end in a bloodbath."

Not all indeed. But there is so many things that could occur in communicating with aliens that a bloodbath - assuming they even have blood - is inevitable. For starters, remember they are not part of our species and so therefore are not bound to our system of thinking

For example - an alien might had its mind had developed in such a way that it is absolutely impossible for us to understand its behavior - they might be not understand our way of greeting, accusation, shock, gratitude, disappointment, anger, etc. completely incomprehandsible, and vice versa. They might consider our radio signal pulses as a load of garbage, while we might be mistakening their signals for something else etc. And how do we know if observe the universe in the same way we does? Such incomprehandsibility might severely, if not making it impossible, for any meaningful out contact, and lots of room of error for misunderstanding.

And then there is morality system to point out. C W Lewis (Christian author of Chronicles of Narnia, who also wrote the Space Trilogy and is opposed to Space Travel and exploration) in his essay "Religion and Rocketry" had once point out that any potential aliens out there might have a morality system so bizarre that we might consider them as unimaginably evil and vice versa. Again, another potential for First Contact bloodbath situation.

I understand your snake island analogy, but the situation I am referring to is a first contact situation between two intelligent species, and I don't think the inhospitability of an environment would pose a serious challenge to a species who could do FTL travel. And while we might believe that aliens would not bother to check on us after recieving, it might be in the interest of alien species who, thinking completely different than we do, might decide coming over is a very good cause of action.

[Starglider]

Strictly, morality and intelligence are completely disjoint; for engineered intelligences one can be altered almost completely independently of the other (excepting of course that complex moral concepts have a minimum level of intelligence to be able to implement). Human psychology has not had a chance to evolve significantly over the span of modern history. The reason for the reduction in violence is primarily that violence is wasteful and inefficient; socities that promote co-operation and assimilate rather than destroying opponents have superior economic and technological progress. On an individual level, intelligent individuals are just as likely to act like selfish assholes, but have the means and the understanding to raid pension funds or kill thousands of people through lax industrial safety standards (and get off scott free) rather than knife people in a back alley for the contents of their wallet.

On an interstellar scale, as far as we know conventional wars of conquest do not make sense. However extermination by kinetic kill vehicle (relativistic or asteroid spam), bioweapon, nanotechnology or more exotic means is quite within the realms of possibility. The primary risk is that a majority of the alien species will have psychology like Darth Hoth; individuals who place no value on the life of creatures not like themselves and who are paranoid enough to want to eliminate any threat, however remote, to their supremacy.

[SpaceMarine93]

"the distances are too vast and the resources are too numerous to really be fought over. Barring enemies that are batshit insane and/or robotic hordes of von neuman machines out to turn the universe into uniform factories that make more von neuman machines, the likelihood of alien beings being an existential threat are nill. You can't fight the laws of physics."

Oh yes, there may be a lot of aliens who are batshit insane, and with good reasons.

First, paranoia. Yes, it is undeniable that distance and resources may be too numerous in the universe to be fought over for, but there is one thing that would get even the most prosperous, far away civilization to start shooting - sheer, undiluted fear and paranoia.

If say an alien species 60 light years away found out about us tomorrow, and we of them, what would they think? Sure, it might be nice that other intelligent life are out there, but what are they thinking? Do the humans know the inhabitants of that planet? How would they react if they do?

They might fear that our civilization is aggressive (which, given light of current situation on Earth they might be right). Of course, they have no proof of that. But would they think waiting to find out is the best course of action? 60 light years away - it would be decades, if not centuries for anyone to go and come back to see. You can never verify it in a lifetime. During this time they could be doing anything. Like building a space fleet or sending a Relativistic Kill Missile to exterminate them all. They have no proof of that, but the worst thing they could do is to do is to put species survival is at stake. And how do they know if the Humans are not thinking along exactly the same lines and sending a missile anyway to kill them, JUST IN CASE?

And remember most of our electromagnetic signals that may allow them to discover us contain information about our various conflicts and wars throughout history, one of the first signals being a speech by a guy in Germany in 1933 talking about committing genocide against anyone not up to his standards of race.

And remember, they would probably have no inhibition against killing us. Humans kill other species all the time, even those with which we share the common bond of high intelligence. As you read this, hundreds of dolphins are being killed by tuna fishermen and drift netters. The killing goes on and on, and dolphins are not even a threat to us. We don't even need to eat them.

As near as we can tell, there is no inhibition against killing another species simply because it displays a high intelligence. So, as much as we love him, Carl Sagan's theory that if a species makes it to the top and does not blow itself apart, then it will be nice to other intelligent species is probably wrong. Once you admit interstellar species will not necessarily be nice to one another simply by virtue of having survived, then you open up this whole nightmare of relativistic civilizations exterminating one another.

And sending a missile at Earth from dozens of light years away is like a targeteer on a WWII bomber dropping bombs on cities. They would feel as much sympathies with the victims of their genocide as that targeteer, so far away in his plane from the ground they could not see the suffering and pain of those they killed

It's an entirely new situation, emerging from the physical possibilities that will face any species that can overcome the natural interstellar quarantine of its solar system. The choices seem unforgiving, and the mind struggles to imagine circumstances under which an interstellar species might make contact without triggering the realization that it can't afford to be proven wrong in its fears.

Got that? We can't afford to wait to be proven wrong.

They won't come to share their science or resources or technology or good will or get our resources or our knowledge or our women or even because they're just mean and want power over us, or even want to bother about us. They'll come to destroy us to insure their survival, even if we're no apparent threat, because species death is just too much to risk, however remote the risk...

"On an interstellar scale, as far as we know conventional wars of conquest do not make sense. However extermination by kinetic kill vehicle (relativistic or asteroid spam), bioweapon, nanotechnology or more exotic means is quite within the realms of possibility. The primary risk is that a majority of the alien species will have psychology like Darth Hoth; individuals who place no value on the life of creatures not like themselves and who are paranoid enough to want to eliminate any threat, however remote, to their supremacy."

EXACTLY. So, ending my analogy we have this image of a self-sufficient, prosperous and very isolated civilization deciding to kill us anyway, because the chances are we are nasty and the risks of not killing us are in their point of view greater than us. Contacting them in anyway might be all the excuse they ever need

[SpaceMarine93]

On a side thought, some people lately had been considering doing exactly the same thing to the aliens if they ever contact us.

[PeZook]

All that "game theory thinking" about relativistic kill missiles ignores a few salient points:

1) Such missiles represent an incredible investment of resources and energy

2) They are not guaranteed to exterminate a species that spread beyond their home planet, even slightly. If the majority of their industrial base is, in fact, off-planet, you will only piss them off.

3) The galaxy is fucking gigantic and there might be other, far more powerful civilizations watching you go apeshit and try to exterminate everyone around you.

It's not a very rational decision if it ignores such glaring problems.

[Sarevok]

RKVs are not necessary. Moving at 0.01c is quite sufficient for interstellar warfare. The times frames of interstellar flight are actually extremely short in a cosmic scale. They only seem long to us because we have very tiny lifespans. Such concerns will not apply to species that do not age naturally or modify themselves to give this capability.

When you take away the need to build exotic near light speed propulsion methods interstellar warfare becomes frighteningly easier.

[PeZook]

So you build your invasion fleet (whoever you are, it's still going to be expensive), float through interstellar space for 2500 years and lo for it turns out the target system is now crawling with armed spaceships who just so happen to have their entire industrial base RIGHT THERE instead of having to set it up from scratch.

I'm sure your war will go splendidly.

[D.Turtle]

If in fact alien civilizations out there are that dangerous to us, then that should mean we should push out into space and expand SETI, not the opposite. As long as we are confined to one little planet, we are vulnerable. Once we are spread out in the entire solar system, it becomes ludicrously harder to exterminate us. If we get the capability to build multi-generational ships that could travel to other star systems, we become almost impossible to wipe out (unless there is some form of FTL out there, and even then it will be quite difficult).

Now, supposing we do not wipe ourselves out, this means there is only a short time where we are detectable (which we already are) and when we become almost impossible to wipe out (which we obviously aren't). The time frame when one becomes the other can be shortened significantly with major investments by the world. However, we currently do not make those investments, as we deem them not important. We will still (hopefully) get there, but it will take time. If however, there is an alien civilization out there that wants to wipe us out, we will not be able to stop them from finding out about us (our signals are already out there, and constantly spreading). So we would have to detect them in time for us to change our priorities to survival. And thats where SETI would come in. It would give us the warning time to do that.

So in fact, your argument ("other civilizations could be deadly to us") argues for more SETI, not less.

[Ariphaos]

One does not need to send spaceships to destroy one's enemies. A single rocket travelling under relativistic velocities

I wrote a calculator for just how 'easy' launching an RKV is:
http://xeriar.com/calculators/relativis ... ass_driver

And those numbers are so ridiculously optimistic that if you think getting something up to .8 or higher of c in less than a couple of light years is any sort of hard science, you are smoking something. RKVs are idiotic compared to sunshine and happiness, and any civilization capable of throwing around sunshine and happiness is going to have such a widely dispersed industrial base that they won't have any similar fear of attack from another culture.

would be undetectable until close by, uninterceptable, and exceedingly lethal to any planet it crashes into.

I don't understand why this myth is still being pushed. It would take very little of the Sun's energy to boil away an RKV, and interception once detected is fucking easy - you know where it is going to hit, if it is going to hit at all.

Anyone who thinks that abomination of a plot in A Killing Star is hard science has not done the math. Building an RKV launcher that gets anything to more than several percent of the speed of light is about as hard as Orion's Arm. Blocking it once detected is about as soft as the Apollo program - a set of solar statites redirects the sun's light into the RKV's path, and it either boils the RKV away or the RKV misses.

The only hard science way to get something to high fractions of c (more than .25 or so) is to build a light sail. That's it. And a light sail is neither stealthy nor difficult to defend against.

This is to say nothing of the effects gravitational perturbation will have on targeting. If you're 100 light years away, it's not sufficient to just monitor Earth's orbit in order to strike it. Pluto, Eris, and most other Kuiper belt objects have sufficient gravity to pull Earth out of the path of your RKV in two centuries' time if you do not account for them.

If you want to ruin a planet, the best thing to do is to point your star at it. But being able to direct more than a few percentage points of your star's energy is extremely difficult, even with statites, so all you may end up doing is pissing the target off, if they notice at all.

RKVs are not necessary. Moving at 0.01c is quite sufficient for interstellar warfare. The times frames of interstellar flight are actually extremely short in a cosmic scale. They only seem long to us because we have very tiny lifespans. Such concerns will not apply to species that do not age naturally or modify themselves to give this capability.

Without unrestricted FTL travel, there is no such thing as taking over a star system in which the host civilization controls access to its star, below Star Wars levels of shielding and damage resistance, and even then it's debatable. The defenders have access to several yottawatts of energy. A star destroyer with a crippled hyperdrive won't survive that. Its crew would die of old age before it could make a dent in the system's defenses even if it could.

You either get a few thousand other star systems to gang up on them and vaporize them, invent magic, or leave them alone.

[PeZook]

You could try and do some stuff with stealthily building up factories in the kuiper belt and throwing missiles at the inner system, but the disadvantages faced by the attackers are so vast, and the "do it undetected" aspect so questionable that most such wars would probably fail miserably.

That's even without directing the star around. The attackers will have to bring their munitions with them and make more on site, which means bringing everything else needed to do that, too. The defenders have everything already there, and they'll have vastly more of everything, from factories to storage space for stockpiles. And they know that, too: if you try to capture some of their infrastructure, they'll just blow it up themselves.

You need an absurd numerical advantage, or a technological edge of epic proportions, and for...what, exactly? Resources? It's easier to mine if people are not shooting at you. Living space? Mine resources and build yourself some. Honorable glory of mortal combat? Well, that at least makes some sense, except people back home won't hear about your exploits, and any civilization with this sort of culture would be too busy fighting it out amongst themselves to wage interstellar war.

Home enemies are much closer, after all.

[Ariphaos]

Ghetto edit: Should read 'most other large kuiper belt objects'...

Targeting at interstellar distances is a losing game without light sails, and with light sails, the target will see you coming years ahead of time.

When you get to galaxy-spanning civilizations, you can have meaningful attempts at strategy in terms of interstellar war, but coordination is going to be a bit of a pain. You won't know how the war is going on the other side of the galaxy for a hundred thousand years, and who knows what's changed in the intervening period.

[Broomstick]

It's not a very rational decision if it ignores such glaring problems.

The most intelligent and technologically advanced species on Earth is nonetheless prone to irrationality - why assume any other technologically advanced species would be different from us in that respect?

Sure, there might be aliens out there that are friendly... and there might be homicidal aliens. They might even be of the exact same species.

I see the risks of contact as the following:

1) Paranoid and homicidal aliens - the kill them before they have a chance to kill us, just in case they want to kill us types.

2) Well intentioned but dangerous - we've seen this on Earth, haven't we? Advanced humans make contact with less advanced human, wrecking havoc on their cultures, spreading diseases, causing all manner of disruption, poverty, inadvertent disease.... the best of intentions can still go awry.

3) Not all aliens are alike - just as not all humans are alike - you have people in the Amazon trying to protect and safeguard indigenous tribes, and people in the Amazon wanting to clear-cut the forest for profit without giving a damn about the primitives, and others who are just nasty bastards who will rape and steal from people they are strong enough to overpower when they can get away with it. It is possible any intelligent alien species we meet could be the same, full of individuals of various motives and morality, some of whom would help and some who would harm.

Balanced against this are the vast distances of interstellar space. If no one has FTL those distances provide protection. It limits our contact to what communications can be transmitted over those distances, and slows conversations to a crawl, but it also protects us. Depending on what's communicated aliens could still impact our civilization for either good or ill, but much less directly.

I'd would dearly love there to be friendly aliens out there who want to be our allies, or at least partners in conversation, but realistically it's stupid to be too trusting.

[PeZook]

The most intelligent and technologically advanced species on Earth is nonetheless prone to irrationality - why assume any other technologically advanced species would be different from us in that respect?

The investment of time, resources and energy required to kill someone in another star system is so vast, that the decision-making process will be more rational by necessity. Sure, if the entire race if a bunch of paranoid homocidal maniacs then it will also have paranoid homicidal maniacs in charge ; But arguably, such a species would not survive very long, even without ancient Protheans coming around to spank them, because they'd have a lot of people to be paranoid and homicidal about at home - namely, themselves.

1) Paranoid and homicidal aliens - the kill them before they have a chance to kill us, just in case they want to kill us types.

Already addressed.

2) Well intentioned but dangerous - we've seen this on Earth, haven't we? Advanced humans make contact with less advanced human, wrecking havoc on their cultures, spreading diseases, causing all manner of disruption, poverty, inadvertent disease.... the best of intentions can still go awry.

Well, the sheer distance and difficulty of interstellar travel shields us from the "white man's syndrome". They will never be able to come over in significant numbers. Unless of course they visit in, say, ten years and set up shop all around the solar system...

I'd would dearly love there to be friendly aliens out there who want to be our allies, or at least partners in conversation, but realistically it's stupid to be too trusting.

Well, I'm not saying "open the gates and give them anything they want", I am merely arguing against going the other way and pre-emptively trying to murder everyone we discover, as this WILL eventually bite us in the ass - if for no other reason, than because launching an interstellar missile at siginificant fractions of c announces our location and intentions to everybody who might be listening.

And gives THEM a good and perfectly rational reason to wipe us out.

[SpaceMarine93]

PeZook:

[1) Such missiles represent an incredible investment of resources and energy]

Its cheaper then you think. At least from what i read about. While it is true that relativistic rockets require enormous power supplies, it is also true that, with increasingly advanced technology, we can power the whole Earth with more efficient means, say with a field of solar cells adding up to barely more than 200-by-200 kilometers, drawn out into a narrow band around the Moon's equator. Self-replicating robots could accomplish this task with only the cost of developing the first twenty or thirty machines. And once we're powering the Earth practically free of charge, why not let the robots keep building panels on the Lunar far side? Add a few self-replicating linear accelerator-building factories, and plug the accelerators into the panels, and you could produce enough anti-hydrogen to launch a starship - or a relativistic kill vehicle - every year. But why stop at the Moon? Have you looked at Mercury lately? ...

[2) They are not guaranteed to exterminate a species that spread beyond their home planet, even slightly. If the majority of their industrial base is, in fact, off-planet, you will only piss them off.]

A very valid point. Maybe we should do something similar as well, you know, spreading into obscured locations across the universe, such as in comets and asteroids, under planetary surfaces, space habitats etc.

Of course, there's the fact that it is possible for a species to be discovered when it already have colonies around its nearby star, with communication at max. So it is very easy actually for any aliens to pinpoint every off planet industrial base and exterminate all of them.

[3) The galaxy is fucking gigantic and there might be other, far more powerful civilizations watching you go apeshit and try to exterminate everyone around you.]

To the problem of other civilizations seeing what we are doing, a dreadful solution had been already been suggested in the novel "The Killing Star":

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"There must be millions of inhabited worlds out there, whatever the experts spout. Some like us, some not. Sooner or later one of them's bound to track back our communications overspill and find us. What then? Under the bed?"

My own imagination was striking sparks off Kirsty's and kindling an evil flame. "Unless..." I began, and actually had trouble shaping the thought. "Unless we got them first. At once, on first contact. A pre-emptive strike, before they could possibly have a chance to find out about us. Hellfire, isn't that a glorious future history for us! A race of paranoid killers, skulking in our own backwater system when we might have had the stars! Clamping down on exploration, communications, anything that might lead someone else to us and make us stain our hands again with the same old crime... Carrying that weight down the generations. What would that make of us?"

"Predators," breathed Kirsty, "Carrion-eaters - no, worse, ghouls, vampires, killing just tae carry on our own worthless shadow-lives."

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That's right, for good or ill, kill everyone and just kill and kill and kill until there's no one left. Not even a more advance civilization could stop all the missiles.

[Sarevok]

So you build your invasion fleet (whoever you are, it's still going to be expensive), float through interstellar space for 2500 years and lo for it turns out the target system is now crawling with armed spaceships who just so happen to have their entire industrial base RIGHT THERE instead of having to set it up from scratch.

I'm sure your war will go splendidly.

Depends on the enemy. If someone launched an invasion of Sol 10000 years ago we would be as unprepared as we were the day it begun. Unless you are fighting peer interstellar powers slowboats are perfectly viable methods of exterminating the galaxy of life.

But just in case what if a planet like us manage to become as advanced as the attackers ? While possible given the time lags involved I dont think it will always end up in astronauts curbstomping aliens who were expecting apes scenarios. Even if we become such a civilization local superiority in numbers is not necessarily assured. Especially against truly ancient opponents that may have been stockpiling ships for millions of years.

[PeZook]

Its cheaper then you think. At least from what i read about. While it is true that relativistic rockets require enormous power supplies, it is also true that, with increasingly advanced technology, we can power the whole Earth with more efficient means, say with a field of solar cells adding up to barely more than 200-by-200 kilometers, drawn out into a narrow band around the Moon's equator. Self-replicating robots could accomplish this task with only the cost of developing the first twenty or thirty machines. And once we're powering the Earth practically free of charge, why not let the robots keep building panels on the Lunar far side? Add a few self-replicating linear accelerator-building factories, and plug the accelerators into the panels, and you could produce enough anti-hydrogen to launch a starship - or a relativistic kill vehicle - every year. But why stop at the Moon? Have you looked at Mercury lately? ...

Except you want the RKV to be undetectable and uninterceptable, and for that it needs to go something like .98c, otherwise its bow wake will arrive at the target years ahead and warn them. Then they'll just slightly alter the orbits of their habitats, and possibly the planets as well depending on their technology and whooomph, your RKV misses.

2) They are not guaranteed to exterminate a species that spread beyond their home planet, even slightly. If the majority of their industrial base is, in fact, off-planet, you will only piss them off.]

A very valid point. Maybe we should do something similar as well, you know, spreading into obscured locations across the universe, such as in comets and asteroids, under planetary surfaces, space habitats etc.

Yes, we should - to ensure species survival in the face of cosmic cataclysm.

Of course, there's the fact that it is possible for a species to be discovered when it already have colonies around its nearby star, with communication at max. So it is very easy actually for any aliens to pinpoint every off planet industrial base and exterminate all of them.

How are you going to exterminate "all of them"? Launch an RKV per habitat? Good luck, you'll do nothing but generate energy for your missiles. And if you can't get it to .99c, the targets can just, you know, MOVE OUT OF THE WAY.

3) The galaxy is fucking gigantic and there might be other, far more powerful civilizations watching you go apeshit and try to exterminate everyone around you.]

To the problem of other civilizations seeing what we are doing, a dreadful solution had been already been suggested in the novel "The Killing Star":<quote snipped>

No, that's a stupid solution, because it presumes you'll always be the first ones to detect the other guys, rather than the other way around. Because your RKV launches will be clealry visible to pretty much anybody in your neighborhood, they will know what's you're doing. And if they're significantly more powerful than you, well...they'll kill you out of completely rational fear.

That's right, for good or ill, kill everyone and just kill and kill and kill until there's no one left. Not even a more advance civilization could stop all the missiles.

How can you presume a more advanced civilization couldn't stop all the missiles? It's a bit like a neolithic tribesman thinking those people riding in funny metal things couldn't possibly stop all the arrows his tribe could unleash!

At worst, they could stop the missiles by destroying your launchers, while their own people are safely in habitats floating around their system.