You might want to talk about galactic occurrence of resources (if you wanted to expand on it). Basically, perhaps there are key resources needed for a society to jumpstart into a starfaring society aside from short-sightedness.
For instance, if your planet lacks uranium, you'll never develop fission and thus never the later technology of fusion and so will be unable to meet the energy requirements necessary for building starships (even if your planet has enough deuterium to fund a starfaring society you never get there because you can't get through the intermediate steps).
Others thing might be a talk about how natural selection is blind and thus inherently "greedy" (take the biggest gain right now and not worry about long-term gain). So it usually breeds greedy sentient species. It's only in the off-chance that it develops a surviving long-term thinking sentient species that they develop into a starfaring society.
By the way, what's the exact plot in the setting you are creating?
Resources such as metals and water are not actually used up by civilization, merely changed into different forms. In the end, they can always be recycled, and a civilization with enough technology and enough motivation will eventually figure out how to recycle them.
From what I can tell, the big issue is fossil fuels. In our history at least, between having an agricultural society and having long-term sources of power (fission, wind, geothermal, solar, fusion), there was a span of 200 years or so when progress relied heavily on using fossil fuels (coal, then later oil and natural gas). If we were to go extinct right now (say, from a superdisease that only affects humans), it's quite possible that another group of great apes would evolve intelligence the way we did, but be unable to undergo an industrial revolution because we've used up the easily accessible fossil fuels. On a planet that didn't have fossil fuels for whatever reason (which might be a lot of them, but we really don't know yet), even the first intelligent species might not be able to carry out an industrial revolution. The most obvious alternatives are wind and hydro power, but in order to make proper use of those you need a good understanding of electricity, and until then, railroads are a non-option, and the resulting lack of transport makes everything that much harder.
However, once a level of technology and science equivalent to our own has been reached, lack of resources is no longer a threat to existence or general progress. We understand that uranium, sunlight, hydrogen, etc can be turned into useful energy, and we're able to figure out how to do it.
The other thing about the Fermi Paradox is that it needs a powerful solution. There seems to be no good reason why a civilization at our own stage of advancement cannot expect to colonize not just its own galaxy, but every other galaxy within hundreds of millions of light years. This does not require superluminal drives; it can be done using known physics and foreseeable technology. Furthermore, there is no obvious reason why intelligent life should have taken 13.7 billion years to arise. So whatever is really going on out there that makes us look alone in the Universe, it's probably pretty weird (and the Doomsday Argument is likely to only make it weirder). Mere lack of fossil fuels does not seem to be something that would be common enough to explain it.
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What if the period in which a civilization exists as a space faring culture that uses ratio waves is only a short, transitory one. A civilization might go through a technological singularity might so drastically change a species' viewpoint that we might not recognize them and they might not recognize us.
We have begun using weaker and weaker transmitters for our radio signals. Perhaps societies fall silent after a time simply because they don't want to spend the energy to send radio signals that are heard from lightyears away.
It's not just about radio waves. They ought to actually be here, even to the point of having converted all the planets in the Solar System into giant computers eons ago. Also, any megaprojects they built (like Dyson spheres or whatever) should be visible to us; nothing like that has been detected.
Given our observations so far, it's more likely that post-singularity beings either abandon our universe entirely, or do everything they believe is worth doing (reaching their omega point) without ever leaving their home star system. Another possibility is that they encode their technology into the quantum realm, having it pervade all of space without us noticing anything yet, but this seems rather unlikely.
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Crazy Kiwi
One of my WIP uses the premise that the only race ever to reach our stage of development or better died out in their own system so long ago that any radio signals that might be detectable by us would have arrived here around the first century BCE at the latest.
Their "legacy", however, got here about the mid 18th century and has taken pains not to be detected by us...
@Meklar
Perhaps they already have and we simply don't recognize the computers for what they are. My entire point being is that, given sufficient technology and directed evolution, would we actually recognize intelligent life if we saw it?
edited 28th Jul '13 12:32:07 AM by Belisaurius
Actually radio signal detection right now is pretty short range, I forget how many light years but I think it was on the order of tens. Unless aliens were to tight beam radio to us, it would be difficult to detect it against the background radiation.
I'm not sure if fossil fuels is the real kicker, I think it is radioactive isotopes which are generated only from supernovas. Getting to wind and geothermal is doable without fossil fuels, albeit difficult and slow, but wind and geothermal doesn't get you rocket ships. Of course, fossil fuels does get you rockets so maybe you do need it. Hmm.
Nuclear energy however I think is exceptionally important to the development of a starfaring society. And once you use uranium or other isotopes, you can NOT recycle it until you get to a much more insanely advanced society. Lack of radioisotopes in the right concentrations can most certainly doom societies.
Alternatively, there could already have been a society that expanded, existed, colonised the galaxy, totally effed up, died en masse and then subsequently exhausted most resources before mostly going extinct (perhaps not completely) or became super advanced (so that we no longer perceive them) or have only small islands left in terminally backward technology on exhausted barren worlds (and thus not detectable except at a close range).
Even fossil fuels are not a problem in the long run. Coal can be produced from wood and oil can be produced from coal. It is certainly not as easy as just getting the stuff out from the ground, but it can absolutely be used to fuel a slower industrial revolution, and it would provide lots of incentives to go to fission/solar/fusion as fast as possible. As soon as you've got access to sufficient fusion/solar energy, resources are essentially endless.
I still think the real issue with fossil fuels is that they seem to be necessary in order to build an industrial society that can engage in large-scale precision manufacture.
I think the more likely path would be for things to remain at an agricultural stage until an understanding of electricity was achieved, whereupon an industrial revolution could be carried out using electricity generated by wind power. One bizarre implication of this is that ships would remain driven by sails for a long time, and powered flight would take longer to develop. Electric trains might be the most common form of industrial-era transport, implying that while societies linked by land could develop together easily, those separated by oceans would be cut off from each other more than was the case in our history.
Of course, on planets with less water, it may be that almost all the land is linked together, and electric trains could take you almost anywhere.
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Fossil fuels doesn't really work since it is possible to grow hydrocarbons. That's pretty much the entire point of biodiesel. It isn't possible to create fissionable elements from scratch as far as we know. The uranium we have now was created in the blast of a supernova and it's not possible to recreate the same conditions on earth.
Still, biodiesel is proven technology so in theory you could create an industrial base, and a highly sustainable industrial base at that, on biodiesel.
If you have enough arable land then growing fuel should last until you can run fusion as a practical source of energy. At that point you're only limitation is how much water you have.
How easy is it to produce biodiesel? Can you do it with pre-industrial technology (or early-industrial)?
Violence is the last refuge of the incompetent.
Yeah, it's pretty easy provided you know what to do. That'd take some trial and error, of course.
Look up turpentine. Modern biodiesel needs modern technology, but producing liquid fuel without access to crude oil is not difficult and has historically been done for a long time (though the substances weren't produced for use as fuel, they could be).
And heck, you can simply burn alcohol, producing even concentrated alcohol has been done for thousands of years. Also keep in mind that the first big step in the industrial revolution was done entirely without internal combustion engines, and steam and stirling engines can run on absolutely anything as long as it burns. It is not entirely unplausible that, given a lack of fossil oil, you'd see all the development that went into combustion engines go into stirling engines instead and thus have car-analogues that run on them and can use pretty much anything as fuel. Of course, a trunk full off coal or synthesized oil will burn hotter and longer than a trunk full of compressed straw and burnable trash, but it's not like the Ford T was a Ferrari. Although speaking of it, that thing could run on alcohol, so there you've got it.
@Meklar
1) Build steam engine 2) Hook up dynamo 3) electrolyze water 4) Use hydrogen and oxygen to fuel rocket
It's quite easy to overlook that electricity is older than cars.
@Belisarius
edited 28th Jul '13 1:57:09 PM by mckitten
In short, both us seeing them and them seeing us should be easy. So far, what we know for sure is that the first one hasn't happened.
1) Build steam engine 2) Hook up dynamo 3) electrolyze water 4) Use hydrogen and oxygen to fuel rocket
It's quite easy to overlook that electricity is older than cars.
That said, apparently fuel is not one of the major costs of carrying out rocket launches, so it might still be economically feasible.
It might also be possible to derive methane from fermenting the waste from farms and sewers. I'm not sure what level of technology that requires to do efficiently, but the principle has presumably been known for a long time.
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Crazy Kiwi
There are quite a number of non-fossil-fuel ways of powering a liquid-fueled rocket and the earliest rockets were propelled by wood-derived charcoal, sulphur and potassium nitrate. So given the development of anything akin to gunpowder and a growing understanding of chemistry, liquid-fueled rockets would have been possible even without petrochemicals.
As already noted, alcohol and electricity are old inventions, steam engines and stirling engines will run happily on any heat source and with the lack of competing technology with an easily-obtained fuel source, they would be forced to develop those technologies far in advance of what we ever managed (and I recall reading that the last generation or so of steam engines were getting pretty damned efficient, albeit partially in reaction to the advent of the petrol engine that threatened the steam industry).
Who knows how inventive they could have got before using up or maxing out their natural resources.
As to detecting them, it's taken us ages to learn enough about the composition of other bodies in our own solar system to suspect that some might be capable of supporting primitive life and ages to even be able to detect exoplanets around relatively nearby stars by their effect on their stars. We're well away from the capability of detecting if those exoplanets have the conditions to support life, let alone if they do/did support it. We're lucky if we can say "yeah, there's something the mass of a couple of Earths in the HZ of that star."
So, short of them beaming high-powered radio signals at us or turning up on our doorstep in their interstellar craft, we've got damn-all chance of detecting them.
Sure, they may have detected us, given we've had people actively bombarding stellar neighbourhoods with radio signals for quite some time now, but that then leaves the question "do they want us to know they're there?"
We're working with supposition - which is great and dandy when writing a Speculative Fiction story, but not so great when trying to scientifically determine whether or not any life out there has reached or exceeded our own technological capabilities.
I'm a strong believer that we will eventually/soon (I hope soon) find proof of extraterrestial life within our own solar system and that future generations may well have proof of extrasolar life. For me the jury's still out on whether or not said extrasolar life is at, or has been at, a similar or greater level of technology than our own.
While I put the "children of Von Daniken" in the same category as the "Lunar Landing Hoax Conspeersy" theorists ("people I would love to take into a dark alley and beat to death with a boxed set of James Burke's Connections"), I'm open minded about the possibility of stealthy visitors/observers from other worlds - I don't hold out too much hope that they have come here, but I'm not going to dismiss it altogether.
For all we know, a bunch of extrasolar visitors swung by at some stage in our past - they could've gotten away with it without being detected from here on Earth right up to fairly recent times, given the state of our technology up until the early 20th Century - saw that we were here and decided to just leave us be and not let us know they were around.
Or they burned out in obscurity still trapped in their own solar system aeons ago.
Or many other possibilities.
Ave Imperator
The most likely explanation to the Fermi Paradox would seem, to me, to be the notion that any civilization that hasn't taken precautions against such things would have an extremely low survivability due to the sheer number of potential extinction level events, not to mention the possibility of self-destructing, that few or no interstellar civilizations, which are quite difficult to destroy, have arisen, and those that have simply haven't gotten around to colonizing our immediate area yet.
There's also the possibility of "Deadly Probes", an intelligent civilization deliberately destroying advanced life, likely via self replicating machines, in that case, we simply haven't been noticed yet due to the relatively large amount of places to look for life to kill combined with the short "lifetime" of radio signals sent thus-far. Assuming said probes would ignore a planet with "rudimentary life", that gives quite a large window of time for them to have checked here for advanced life and fail to find it.
edited 29th Jul '13 1:52:30 AM by Archereon
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If advanced civilizations are forcibly killed off, it is almost certainly through artificial efforts (either their own or someone else's). Nature just works too slowly.
edited 30th Jul '13 12:23:35 AM by Meklar
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Crazy Kiwi
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For most of them. I'd accept that one or two just got friggin' unlucky and got creamed by nature.
But yeah, for the rest to be killed off, they'd have to be killed by someone else or have wiped themselves out.
There is a belief that the majority of intelligent life ends up destroying it'self as soon as it discovers E=mc^2 so yes, the extinction level event may be entirely artificial.
Granted, we haven't managed to blow ourselves up but we were damn close (i.e. able archer and cuban missile crisis).
@Wolf Glad to see someone else has watched Connections. Please don't waste a DVD box set beating the flat earthers to death. Jim Burke's work is more valuable than the removal of certain people from the gene pool.
Ave Imperator
@Meklar: A Gamma Ray Burst of sufficient duration would do us in nicely with little hope of predicting it and no hope of stopping it, just burrowing as far underground as we could to avoid the worst of it, and even that's no guarantee.
Another possibility that supplements this, for our galaxy at the very least, is that our galactic nuclei might go through a cycle of increasing and decreasing activity, which could potentially threaten even an interstellar civilization with, if not outright extinction, a degree of stagnation that would prevent much expansion until the emission levels of the GN declined again. This hypothesis also does a nice job of explaining the semi-regular mass extinctions that appear to have occurred at various points in history.
The reason I favor a naturally occurring solution to the paradox rather than say, your suggestion that a civilization might do all it found worth doing without leaving its home system, is that just as you said, the paradox requires a relatively strong solution, very little can be said to be guaranteed about the ideologies of every extraterrestrial civilization that ever could arise. Thus, the argument that it is in intelligent life's nature to destroy itself fails to be a convincing solution to the paradox on it's own.
The deadly probes suggestion fares a little better, since its assumption merely requires one or more civilizations to act in a particular way rather than all or virtually of them, though it has the problem of requiring the aggressive civilizations and/or their creations to be especially successful, and one would still expect evidence of mega-constructions like Dyson spheres and so on if said civilization was active in our galaxy.
Yet another solution to the Fermi Paradox that does not require any civilizations to behave in any particular way is the possibility that conditions which are suitable for the development of intelligent life are exceedingly rare even if single-celled life is practically ubiquitous, and/or that such conditions are generally short lived, giving little time for civilizations to arise in the first place, thus addressing the paradox by greatly cutting down on the number of potential interstellar civilizations, and making the explanation that other civilizations are too far from us in space and/or time to communicate, either dying out, switching to methods of communication we cannot currently detect, or merely not bother to communicate with entities that could be likened to ants in comparison to themselves (though that once again makes assumptions about how other civilizations will/would behave), since the reduced number of interstellar civilizations makes it more believable that someone hasn't colonized the whole or even most of the universe already.
edited 30th Jul '13 8:27:41 AM by Archereon
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If it's just for story telling reasons then you could claim that intelligent life tends to logic bomb it'self after a certain degree of intelligence with the chance increasing with intelligence. Thus you can have a Dying Race of geniuses who are teetering on the edge of catatonia every moment of their waking lives.
There is absolutely no evidence of this, however.
Ave Imperator
There's no real reason not to use any particular solution to the Fermi Paradox, given that it requires some sort of solution to explain why the entire universe hasn't been converted into a giant computer by now, or whatever it is a transient post-singularity intergalactic civilization would do with the cosmos.
Then again, there's always the possibility that any sufficiently advanced technology is indistinguishable from nature (at least to the intelligent entities that are part of this device), and what we perceive as natural is actually the result of a universe spanning intelligence that colonized the universe long ago, which I'm sure has been used in science fiction before. The problem with that is that theories like that are simply unscientific, given that they rely on assumptions that are non-falsifiable, at least from our end.
edited 30th Jul '13 10:33:02 AM by Archereon
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...Hitchhiker's guide to the galaxy?
"On countless worlds throughout the galaxy life emerges and grows over the course of vast aeons. Eventually some of this life becomes intelligent enough to develop technological civilization. Drunk on their newfound power over the natural world, most intelligent species exhaust the very resources on which their technological civilization depends. From there they decline; whether back to barbarism or to a less intensive form of technology, the fact that they will never leave their homeworld remains unchanged. Thus they remain unable to contact us.
Those few civilizations which see the crunch coming and plan for it survive and move on to spread throughout their home solar system and on the the stars.But they are still the proverbial needle in one heck of a vast haystack, and as such there is no guarantee we'll meet before [U]we[/U] go the way of so many other intelligent species."
This hypothetical solution to Fermi's Paradox is a framework on which I structure a 'Verse currently under construction. What is done well here, and what needs work? I eagerly await your response.