We're going to try something new here at the blog that dare not speak its name: a Sunday topic for general discussion not tied to current events, evolution or religion.
Today's topic is a new trope I've noticed wending its way through SF. If we assume that intelligent life is not rare and that faster-than-light space travel is not difficult, then there is likely to be a highly xenophobic space-traveling race. This race will see any other intelligent species as a threat to itself (because it is a threat to any other intelligent species) and do its best to wipe such a race out as early as possible. In other words, our attempts to contact other intelligent beings might be a signpost saying "Hey, kill us next."
I have two questions. First, is this scenario likely assuming, for the sake of argument, that other intelligent life exists? Second, should we change our actual behavior (SETI, space probes with star maps, radiating radio waves, etc.) because of the chance of FTL capable xenophobes?
36 comments:
I think SETI is a waste of time and money simply because the odds of intercepting a radio signal from an intelligent, technologically advanced race are so astrnomically small as to defy calculation. It would require that a race similar to our own live in close proximity in both the space and time dimensions.
I remember my reaction to the movie "Contact". I thought it was the silliest load of mystical fantasizing not to originate in a religious context. I look at SETI as a kind of religion.
Sorry for transgressing the no religion rule, but these things are all tied together.
I think they'd more likely be friendly, but I doubt they would attempt to make actual physical contact with humans or with Earth. The War of the Worlds is probably the most realistic Sci-Fi story as far as the consequences of visiting a new planet that hosts biological life. Strange viruses, bacteria and parasites would pose the greatest danger.
I doubt that they would attempt any communication with us either, they'd probably just study us and monitor our long term progress to see if we would become a threat.
SETI isn't a waste of time, because you're simply assuming that there are effectively no other intelligent races.
You may have the values for one or more variables wrong. In fact, based on our prior discussions about this very topic, we disagree about the probability of many variables.
No, we ought not keep a low profile. Maybe there are tigers out there, and maybe there aren't, but we'll never know if we don't venture forth.
The human race is doomed anyway if we stay cooped up in this one solar system, so in the (extremely) long run it doesn't matter if we get assimilated by the Borg or simply wait for The Extinction Event to occur, in whatever form it may take.
Oro,
I'm not arguing that there are no other races, I'm assuming that the odds that such a race lives within a distance at which we could detect their radio signals, and also that they happened to have developed their civilization in time to be at roughly the same technological level of progress as us just as we have developed the technology to detect far away signals is fleetingly improbable.
At what distance do you think we could detect radio signals from another planet in another solar system? We have just recently developed the sophistication to detect the presence of Jupiter sized planets in orbit around nearby stars, and even there we are measuring the gravitational effects of the planet due to parallax of the host star and not actually the radiation emitted by the planet. I doubt that we could detect a 50 megaton nuclear explosion in orbit around Alpha Centauri.
Of course, I haven't done the math.
Even if there are/were aliens, the galaxy is a big place. We should just leave an entry on the galactic craigslist missed connections.
Peter,
What do you think we would do if we encountered another civilization? The only purpose to attack another civilization would be to take over their planet, but I've never considered that a plausible scenario. Just getting a small party to a distant planet that supported life would be an incredible accomplishment. So they are going to set off some kind of devastating biological weapon to kill off the inhabitants, then take their chances trying to survive the local microbes and breed a new civilization? I don't think so.
Contra Oro, if we don't off ourselves then our Sun should continue to support us for another 5 billion years. If we can develop the technology for interstellar space flight, then we will have developed the technological sophistication to keep our own planet inhabitable.
Oro, I am shocked by your doomsday scenario. Have you swallowed a bad batch of St John's Wort?
I meant habitable.
I will have to find my own posts on this. But let's start with the original question.
I think the odds of there existing a non-benign alien race in your scenario reasonably good, but what are the odds that we'd be the first other race to encounter it? A belligerent race would end up fighting a series of wars, while other friendly races didn't, leading the belligerent getting beaten down. It would have to be the case that belligerence was more likely than friendliness for this to be a real problem.
However, the scenario I find far more likely is indifference. The gap between us and any other species is likely to be millions of years. I find it laughable to think that our own descendants that far time down time stream would be comprehensible, much less aliens. The real trope in those SciFi novels isn't the many aliens and FTL, it's the idea that they're all roughly the same level of development, meaning anything within a million years of each other.
Based on this, contra Duck I don't see getting here to be much of an accomplishment (Mr. Cohen did say FTL was possible). As for what they'd want, it would be energy and mass. I doubt they'd have much interest in conquering the Earth, but they might like to build some nice things out from it. Or maybe just grab all the photons from the Sun for themselves. Or conduct large scale physics experiments.
Finally, M Ali is quite correct, given Mr. Cohen's assumptions there is no such thing as "low profile".
Duck:
What you, Mike, and AOG said are what David means by "there are effectively no other intelligent races" - there may be/will be thousands of them, but so separated by time and space that effectively each species lives independent of each other.
That seems like the most likely thing, and your points about our ability to detect others are true as well.
My point is simply that we'll never know if we don't look.
Gross conditions suitable for human life may continue for another few billion years, but that doesn't mean that there aren't a million finer details which could end us. And even if we did last another five billion years in isolation, that seems both sad and pointless to me.
But I've always been a curious sort; maybe most people are content not ever knowing what's beyond the hills.
Oro,
I am curious, but I just think as a matter of funding priorities that SETI should be way down the list. We're scanning the skies now looking for other phenomena, like black holes and dark matter, and I think that it is just as likely that we discover signals that indicate intelligent origin that way than by setting up a separate program to look for only that.
SH, using our planet or sun for mass and energy would be a waste of what our solar system has to offer, another intelligent race and a planet that supports abundant life. They can get matter by mining the planets and asteroids in their own solar system, and I doubt that any civilization would grow to such an extent that it could not satisfy its energy needs through the exploitation of its own sun. If not, they would travel to the nearest available sun to exploit its energy.
That's why I find most sci-fi invasion stories so implausible. Like Steven Spielberg's remake of the War of the Worlds, where the aliens were grinding us up for biomass. That's just silly.
Like Oro is of them, I think that the aliens would be very curious to study us. You don't acheive the technology to travel interstellar space if you are not curious.
-- using our planet or sun for mass and energy would be a waste of what our solar system has to offer, another intelligent race and a planet that supports abundant life.--
I fail to see why an alien race would a priori care about either. A space faring race may think of vacuum and zero gee as the best type of environment for life, making the Earth as it is undesirable.
In a related vein, I don't get Oroborous' "alone" comment. I suspect the diversity of the transhuman future will make longing for alieness seem quaint.
-- They can get matter by mining the planets and asteroids in their own solar system --
Ah, you're engaging in another trope, the unitary species. In this case, you are presuming that if any members of a species can mine their own system, that's the same as all of them. Why couldn't there be minorities who would like to own more mass and energy and see other solar systems the way we would see unsaturated markets?
-- I doubt that any civilization would grow to such an extent that it could not satisfy its energy needs through the exploitation of its own sun. --
Those are referred to as Type III civilizations. So not everyone shares your doubt.
-- If not, they would travel to the nearest available sun to exploit its energy. --
Maybe that's ours. If not, repeat as necessary until they arrive here.
Of course, this is whole discussion is predicated really upon one assumption: relativistic, never mind FTL, is practical.
If it is not, and there are all kinds of reasons to believe this ineradicably true, then, sadly, we are pretty much stuck here.
And They are all stuck There.
Fermi's paradox is overhyped.
Well, call me a liar:
World's Largest Telescope
European funding has now been agreed to start designing the world's largest telescope. The "Square Kilometre Array" (SKA) will be an international radio telescope with a collecting area of one million square metres - equivalent to about 200 football pitches - making SKA 200 times bigger than the University of Manchester's Lovell Telescope at Jodrell Bank and so the largest radio telescope ever constructed. Such a telescope would be so sensitive that it could detect TV Broadcasts coming from the nearest stars.
Still, that isn't a very large neighborhood.
[S]erious attempts at expanding beyond the solar system are centuries off.
I'll get excited about what's beyond the hill once a decent bike's been invented.
"Centuries" may be a bit pessimistic. I agree that such technologies are many decades off, but beyond that, who knows ?
It could be centuries, or even millennia, or it could be 73 years from now.
My guess is that the "decent bike" will come from adapting technologies developed to solve other problems, just as railroads became practical once metallurgical technology developed for cannon was applied to making rails.
I just think as a matter of funding priorities that SETI should be way down the list.
I agree. However, since SETI costs only a few million per year, (which, to a staggeringly, overwhelmingly wealthy society such as ours, is near-literally nothing), I think that we're not really out anything by funding it too.
In a related vein, I don't get Oroborous' "alone" comment. I suspect the diversity of the transhuman future will make longing for alieness seem quaint.
It's not a desire for novelty. It's that, just as a solitary marooned castaway, or a hermit's, lives are pointless and irrelevant, (except potentially in a spiritual sense), so too would our existence be so much more if we had Others to interact with.
Of course, if we do find Others who are a million years ahead of us, even assuming that they don't kill or enslave us, half of the human race will probably drink itself to death, if the history of superior/inferior cultural contact among human societies is an accurate guide.
If [FTL drive, or at least fast travel, isn't possible], and there are all kinds of reasons to believe this ineradicably true, then, sadly, we are pretty much stuck here.
What about hibernating technologies, cryogenic or otherwise, or worldships ?
It's true that leaving the solar system would be a one-way voyage, at least with regard to one's family, friends, and era, but we could still spread out, and maintain communication.
Peter makes the very perceptive point that our hopes or fears about aliens are shaped by how we feel about other humans at different times in history.
I think there's almost certainly life elsewhere because you only need some basic, very common elements for the conditions, and because life appeared on earth practically as soon as the conditions made it possible.
But trying to guess the likelihood of human-like intelligence with space travel technology evolving elsewhere is a different thing altogether. We don't even know how likely it was that language developed, which I'd have thought would be a basic pre-requisite for technological development.
hey skipper's point has some merit but is hardly decisive. Our sun is only 5 billion years old and the universe is 11-15 billion years old. There are billions of sun-like stars in our galaxy, and many of them began their life billions of years before ours. Our galaxy is 100,000 light years in diameter, so at the speed of light alien races would need at most 100,000 years to visit us. If sentient life developed at the same pace on all sun-like solar systems, then we should have been visited many times over the last billion years.
The other thing about searching for radio waves is that the radio wave age may end up being pretty short. It's barely 100 years old now and I'd be surprised if it survived another 100 years. The chances that two interstellar neighbors are going to both be in the radio age at the same time is infinitesimal. It seems to me that an spacefaring race that wanted to attract the attention of other spacefaring races would use some other means to attract attention. For example, put a shroud around a star that can be switched between transparent and opaque and use it as a sort of Dyson signaling lamp. Then you get your message out at light speed over a much greater distance (as well as a lot of energy).
Also, note that we're being told that interstellar war doesn't make economic sense and that we have to expand beyond our solar system to ensure our long-term survival. If we sent a world ship on a one way trip to a habitable planet (assuming that we can figure out from telescopy which planets are habitable) what would we do if we got there and found a pre-industrial or even industrial civilization. Harry Turtledove not withstanding, doesn't it seem likely that any interstellar race can have its way with any race that is not yet in space?
If we sent a world ship on a one way trip to a habitable planet (assuming that we can figure out from telescopy which planets are habitable) what would we do if we got there and found a pre-industrial or even industrial civilization.
Good question.
If it were me, I'd dance a jig of joy. After all, first alien contact is better than another human colony.
But rather than relying on telescopy alone, I think that it's likely that we'll be sending out probes first, to identify the most promising targets, before committing our colonists.
David,
It depends on what kind of weaponry it brought with it. Unless you planned your mission for conquest, you're not likely to have the means available to wage a war.
Are you going to kill off the dominant race or live amont it and subdue it? If the former, how will you kill them off? Atomic bombs? Bio-weapons? Or come to the surface and zap them one at a time with energy beams?
These kinds of decisions can't be made in a vacuum prior to the mission. You need to know your enemy before you formulate a strategy. So once the exploration ship has had a chance to study the race, then it can go about developing the appropriate weaponry.
Bio-weapons would be the most efficient, but you would need to study their biology in order to design the best agents. So you'd need to send scouting ships down to some thinly populated, rural area and take captives, probe their orifices for genetic samples, and maybe take some living prisoners back to the ship. Hopefully you will have chosen the samples from the lower socio-economic strata of their society, so if some of them talk to others about their encounter they will be ridiculed and not believed. Secrecy is important.
Then you are going to need to set up manufacturing facilities to create the billions of pounds of biological agents necessary to blanket the entire surface of the planet, along with the entry and dispersal vehicles. This could take decades.
Plus, they would need to solve the problem of deveoping vaccines and antibiotics to enable them to live on the surface and survive.
It's a huge undertaking, even for an advanced race. But there is always the Cortez option. Just show up and start blasting away at the big shots, and hope that you are able to cow the natives and make them think you are gods. Then you can live the life of a plantation tyrant.
I would just drop rocks on them.
Duck;
If you have a spaceship capable of crossing interstellar space and colonizing a new solar system, you have everything you need to wage war.
Mr. Cohen;
What about building a giant Fresnel lens at L1 and roasting them?
P.S. I presume you have all read "The Screwfly Solution".
None of you have considered the real question about our plan for fighting intergalactic invaders...
What would Jesus do?
PJ, Oroborous:
Our sun is only 5 billion years old and the universe is 11-15 billion years old. There are billions of sun-like stars in our galaxy, and many of them began their life billions of years before ours.
Yes, they did. However, that does not mean there has been enough heavy elements to form rocky planets through that entire span. Consequently, it is far more likely that essentially all stars with habitable planets are roughly the same age as our sun.
Even ignoring that, there are barriers to interstellar travel that appear fundamentally insoluble.
First, there is a "Goldilocks" region of the galaxy that is capable of producing producing stars and planets capable of sustaining life. Notionally, it is the middle third of distance from the center to the rim.
Inside that distance, and the density of stars become such that radiation, and novae, would simply wipe out all life.
Outside that region, stellar density is so low that there aren't enough heavy elements to produce rocky planets.
The GR avoids both those extremes.
In the solar neighborhood, the stellar density is about one star per cubic parsec (one parsec is 3.26 light-years).
Unfortunately, it is impossible to throw anything other than notional numbers at the problem, but let's assume the chances of a star in the GR possessing a habitable planet is one in 1,000. Therefore, roughly speaking, there should be one habitable star system for every 1,000 cubic parsecs. Doing the math (and hoping I make no horrid mistakes that AOG will spot by mere casual inspection), and that works out to a sphere with a radius of 20.6 light years (that radius increases to 43.5 light years if the odds are one in 10,000)
Consequently, it may well be impossible to detect which star, if any, has a habitable planet, meaning a civilization would have absolutely no idea in which direction to proceed. Looked at another way, a shot in the dark would require passing 500 stars to stand a 50-50 chance of passing one with a habitable planet: that amounts to a 10,000 year journey, at the speed of light just to get within a coin toss of success.
Unfortunately, no matter the hibernation technology one might dream up, quantum mechanics pretty much ensures your DNA would be trashed during that interval.
Furthermore, that 10,000 year estimate is, unfortunately predicated on all the stars being conveniently arranged in a line. Which leads to the second problem: changing direction and stopping. Provided one is traveling fast enough to get such a journey done in less than geologic time, one has to accumulate a great deal of speed. Which makes changing direction, even with gravitational assist from a star, virtually impossible. At even .1C, an object would transit the earth's orbital radius in 80 minutes. That simply isn't enough time to cause any significant change in direction, never mind stopping. Roughly speaking, an object going .1C (average) would change direction by 7.5 degrees through the sun's gravitational pull, even if it grazed the sun's "surface" as it went by.
Which leads to the third problem: mass. The faster any object goes, the greater its mass. This increase becomes asymptotic as one approaches the speed of light. In other words, the energy required to accelerate any object with any mass to the speed of light is infinite. Meaning the faster you go the more energy you need to not only go faster, but stop at the far end.
That stopping thing is the problem most people forget to think about.
This is why I think the Fermi paradox is overhyped. Limitations on detection, the extreme difficulty of changing direction, never mind stopping, and the nearly unimaginable energy required to accelerate to a speed even remotely close to that required are all fundamental problems.
If any one of them is insoluble, then the paradox simply doesn't
exist, and we are irrevocably relegated to the solar system: there simply is no getting There from Here.
Skipper:
That is an excellent explanation of why we don't yet possess sufficient technology to go star-hopping, ASSUMING that your notional numbers are in the ballpark.
My first objection is that we also don't yet possess sufficient technology to confirm either that outside of the Goldilocks Region, stellar density is so low that there aren't enough heavy elements to produce rocky planets, or that the chances of a star in the Goldilocks Region possessing a habitable planet is one in 1,000.
Possibly there are planets in the hinterlands, and maybe potentially habitable planets abound in the GR.
But if the current trendline in telescopy continues, we'll know the answers to those questions long before we're ready to send humans on the long outbound.
My second objection is that we don't really need "habitable planets" to be waiting for us at the target star, we only need there to be a lot of raw materials there to work with.
We can either move & terraform an existing planet, or we can just tear apart whatever's there and construct space stations.
If we do that, then we don't have to try to detect livable planets on the fly; we'll have our course and maneuvers plotted before we leave.
Of course, the ability to do such things seems likely to be a long way off, but we can lay the groundwork now by doing the basic detection and remote exploration.
So maybe we are too-tightly embraced by Sol, and maybe we aren't. I say that it's worth the effort to find out which it is.
SH
You're ignoring that the most important consideration is not technology, but logistics. That's not surprising, as most terrestrial war planners through history ignored this as well.
Skipper:
Darn.
Perhaps we could just drop leaflets then?
Duck;
Not at all. I am only presuming sufficient logistical support to colonize a stellar system, as I stated in my previous comment. If the ship isn't carrying either that or enough fuel to get back, either it's a suicide mission or the passengers expect to revert to a pre-technological existence. I don't find either of those plausible.
Oroborous:
My first objection is that we also don't yet possess sufficient technology to confirm that outside of the Goldilocks Region ... there aren't enough heavy elements to produce rocky planets.
Actually, I believe that question is settled. Even if it isn't stellar density plummets in the outer regions, making the distance problem even more severe.
... the chances of a star in the Goldilocks Region possessing a habitable planet is one in 1,000.
You are right. Who knows? However, it is far likelier the real density is far less than 1:1000, rather than more. After all, presuming there are a billion star in the Milky Way, we know the real density is somewhere between 1:10E9 and 1:1. There is a heck of a lot more number space between 1:1,000 and 1:1E9 than there is between 1:1000 and 1:1.
I don't know what the outer limit may be for detecting a habitable planet (that isn't already the beneficiary of a civilization), but I'll bet there is plenty of reason to expect it lies well inside 20 light years.
The inverse square law is relentless, which means the current telescopy trendline cannot possibly continue indefinitely.
Does that mean we should simply give up on the notion?
Of course not.
But to presume that the Fermi paradox actually exists begs some very, very, difficult questions.
SH:
Duck is right about logistics.
If one was to colonize a new continent, one would pick a transport ship ahead of an aircraft carrier.
Unfortunately, the former would likely succumb to enough sufficiently determined inhabitants, and the latter couldn't sustain itself.
Can't have everything.
Skipper;
That's not my claim.
I am fine with the transport ship analogy, but what's in the ship? If I were organizing the expedition, the transport ship would be filled with lots of computing power and fancy matter manipulation devices so the colony could build what it needed instead of hoping they had thought to pack it. And if they can do that, cranking out weapons on site is easy.
There are two further points —
First, the colonists have time. It's likely the native inhabitants won't even notice them until the weapons hit.
Second, the colonists would come from a civilization with heavy space industries and would naturally bring that capability along, so they won't have much of a resource problem.
So, you have a ship that can build just about anything known to its civilization and the time and resources to build it (if they've waited the multi-decade or even multi-century journey, they can wait another decade or two). They have the high ground from which to attack without threat of retaliation, their industrial base invulnerable. What, exactly, is the logistical problem I am overlooking?
SH:
Mass.
Of course, the all-purpose plot device known as matter manipulation devices will get you out of that bind.
If you are dealing with pre-industrial age natives, then there is probably time. But how likely is it that a spacefaring civilization would be undetectable, and in the guise of a cargo ship, undestroyable, to a civilization of even our ilk?
Mass? I think that odds that the habitable planet is the only body orbiting the star is too unlikely to be worth considering. Presuming a solar system anything at all like ours and the colonists have all the mass they could want.
As for time, if such colonists arrived today, set up a base on the Moon, and started dropping rocks on every electrical power generator on the planet, what exactly could we do to stop them?
P.S. That said, I don't see how a matter manipulation device would get around not having the mass in the first place.
I also don't see matter manipulation devices as a "plot device" — are you saying that the colonists wouldn't have things like computer controlled milling machines? Silicon chip lithography machines? 3-D printers? I think it's reasonable to think they'd have working versions of anything we currently have a least prototypes for.
I think it's reasonable to think they'd have working versions of anything we currently have a least prototypes for.
Yes, but where are they going to get all of the right materials? Should they assume that the moon of the planet they wish to colonize will have every mineral and chemical compound in ready supply? Even if it does, it has to be mined, refined, smelted etc. before it can be used to fabricate whatever it is they need. On Earth we take it for granted that any industrial material we need is readily available at a competitive cost. All this infrastructure won't be there when the colonists arrive. They will have to build all of it. That is what I mean by logistics.
Just do a thought exercise about provisioning a star transport with every kind of machine and tool needed to bootstrap a fully functioning industrial society, as well as all the raw materials to get it off the ground until local resources can be exploited, not to mention the personnel with the requisite expertise in all of the different areas to set it up and operate it. Unlike Eurpoean colonists to America, they won't have recourse to regularly scheduled trade routes back to the homeland to bring in the artifacts and materials that aren't available in the new colony.
SH:
By Mass, I meant the mass of the ship you are attempting to accelerate, then stop.
For a problem that already faces fundamental, non-technological, constraints, tossing a whole lot of M next to the V^2 will only make matters a whole lot worse.
And by plot device, I mean presuming that every problem is solvable by an inevitable technology.
Granted, that is far more likely with manufacturing technology than propulsion. But even so, it is hard to see how even the most optimistic technological forecast can envision the required spectrum of manufacturing capability without entailing thousands of tons of that dreaded mass stuff.
Duck;
I am still not conveying my point. What you write is true, but my point is that such support can be presumed from the fact that a colony ship was sent. That is, you don't need anything more than what's required for colonization in the first place to deal with a non-space traveling indigenous population. I.e.,
"If you have a spaceship capable of crossing interstellar space and colonizing a new solar system, you have everything you need to wage war." [emphasis added]
Claims about the feasibility of such a ship is completely irrelevant to my argument.
P.S. Why restrict yourself to a moon of a single planet? It's an entire solar system. There are hundreds of good sized moons and planetoids in our solar system, why wouldn't there be elsewhere too?
Peter,
I drink beer, it helps cool the brain.
Peter:
Yeah yeah. When I see them do it in limerick form, then maybe I'll be impressed...
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