Legend has it that the highly esteemed Nobel laureate Enrico Fermi interrupted a group of scientists at Los Alamos who were discussing the likelihood of intelligent life elsewhere in the galaxy while resting from the tiresome task of inventing the atom bomb. These fine lads were convinced of the high probability of extraterrestrial intelligence, to which Fermi succinctly retorted “So, where are they?” I don’t know about the actual truthfulness of the legend, but this issue has since become widely known as the Fermi Paradox.
The Fermi Paradox results when one examines ideas such as the Drake equation and its implications for the ubiquity of intelligent life in the galaxy. However, equally valid assumptions about the ability of life to colonize the galaxy indicates that the first species to arise with stargoing capabilities should propagate throughout the galaxy in the veritable cosmic blink of an eye. There have been numerous hypotheses put forward in an attempt to resolve the seeming paradox, but they all fall into one of two categories:[ul][li] The aliens exist[/li][li] The aliens do not exist[/ul]When I spend time pondering this issue instead of doing something productive, I generally restrict myself to considering the Milky Way galaxy, on the rather large assumption that any intelligent life in other galaxies would be too remote to enable meaningful contact between the two species. Therefore, I subscribe to the First Come, First Served hypothesis. In other words, we are among the first, if not the first, to attain sentience in our galaxy. Or at the very least, we are currently the only species capable of spaceflight that hasn’t destroyed itself or been the victim of a cosmic catastrophe. If we proceed to colonize the galaxy, this will necessarily prevent any other species from reaching our level of intelligence.[/li]
When I am in a more optimistic frame of mind, I ponder the Percolation Theory resolution to the paradox, which would allow for the existence of multiple ET’s; however, realistically I see many problems with this solution, so I usually revert back to the doom and gloom of the uniqueness of our existence.
Though this discussion is by its very essence on the boundary between knowledge and ignorance, I would like to query that most venerable gathering of minds – the SDMB community. So how do you resolve the paradox? Which answer do you deem most likely, and why? If they aren’t here, why not? If they are, why are they being so damned coy about it?
I believe 99.9999999% that there’s intelligent life out there.
I believe that 99.9999999% of the people who say they’ve seen aliens have actually just seen the bottom of their bottle of brandy.
And that First Come, First Serve theory is not mutually exclusive to all other theories. The universe is freaking huge! If we travelled at the close to the speed of light it would still take billions of years (relatively) to reach the end of what we’ve, thus far, been able to see. In other words, we could colonize every planet we ever come across for the next 100,000 years and still not kill off any other intelligent species in the process. Or we could find aliens right around the corner. The future is wide open.
Of course, I like Calvin’s theory the best:
“Sometimes I think the surest sign that there’s intelligent life out there in the universe is that they haven’t come to Earth yet.”
[sub]or something like that[/sub]
As Enderw24 said the universe, even just our own galaxy, is freakin huge.
Mind you humans have been on the scene for only an eyeblink (if that) in the cosmos. Let’s say that civilization on earth has existed for 6,000 years. That’s nothing. Now consider that we’ve only been able to even listen for other life for the last 50 years or so. That’s really nothing. We’ve only barely gotten into space in the last 30 years or so. That’s less than nothing. We haven’t even left our own solar system yet. That truly is nothing.
What if Einstein is correct and sci-fi writers are all wrong? You can never ever travel faster than the speed of light and there aren’t any tricky shortcuts (wormholes, Warp drives, etc.)? If so that makes colonizing the galaxy a bit of a pain. Getting to even a fraction of light speed (say 10%) requires more fuel for a chemical rocket than I think exists on earth.
Who’s to say LGM’s (Little Green Men) even want to colonize the galaxy like we would? They might but ascribing human motivations to them is probably an error.
All in all I’d say there are lots of reasons we might not be up to our eyeballs in LGM.
My take on the hypothesis is to dismiss it because it contains a huge assumption: that alien(s) think just like us. “Hmmmmm” sez Fermi “If I were an alien, I’d spread out all over the galaxy and send ‘billuns and billuns’ of messages all over creation. Since there’s no evidence that aliens are doing this, there must be no aliens, right?”
Wrong. Sorry 'Rico. Obviously you didn’t read much of Campbell’s SF (contemporary with you). Aliens don’t have to think like us. Some posiblities:
[li]We’re the only species with a drive to expand (a world of redwoods, say)[/li][li]We’re somehow taboo.[/li][li]They are communicating, but we can’t notice it (how would a hyper-intelligent shade of the color blue communicate?)[/li]
The point is that Fermi’s theory is only useful if all other aliens follow the only example we’ve got: earth species. When/if we find a second ecosystem we’ll be able to compare. Until then, Fermi blew it, IMHO.
This is a puzzle that’s stumped brilliant minds? I mean, come on…the possibilities are endless. Maybe aliens who tried expanding their territory have discovered that it’s unprofitable to have to deal with otherworldly pathogens. Maybe aliens are out there, but our nitrogen/oxygen atmosphere is not hospitable to them. Those two occurred to me in the first few seconds. Even if it can be taken as a valid assumption that all space-faring races are likely to attempt to expand their territory if possible, there’s no reason to assume that they are likely to come here.
Enderw24, I hope to confine this debate to the existence of spacefaring-capable species within our own galaxy. I agree with you that the probabilities are high concerning sentient life somewhere in the universe. However, Andromeda is the closest galaxy to our own, and it is 2 million light-years away, so this precludes any meaningful dialogue without some type of new physics.
Whack-a-Mole, so you prefer one of the Stay at Home hypotheses. Personally, I don’t think you can assume every ET will want to stay on their original planet. If just one species does decide to expand, then they should have colonized the galaxy by now (if they exist).
Technical limitations are another factor, but I assume that no unforeseen “miracles”, such as exceeding the speed of light, are even necessary. Using currently known physical limitations, engineers have proposed propulsion systems that would reach 10-20% the speed of light. Fermi (and others) factor this into their examination of the issue, yet still you must conclude that with a latency period of 400 years and travel at 10% lightspeed, the galaxy would be fully populated in 5 million years. Not a very long time by cosmological standards.
Fenris, the same counterpoint applies to your objection. Basically, your scenario holds only if the number of ETs is extremely small. If there are more than a few, it seems highly unlikely that they ALL want to stay at home, or consider us taboo, etc.
SPOOFE and cmkeller, I think the paradox is deeper than you consider it. If just one alien race embarks on a colonization directive, we should be able to see some evidence of it, regardless of whether they decided to settle on Earth.
Space is big. Very, very big. As big as people thought space was, if inlation theory’s on the money, it might be even bigger than that. I wouldn’t be particularly surprised if we’ve got the Milky Way to ourselves.
Other things get in the way, too. What is intelligent life going to do if it evolves on a planet where, say, iron is extremely scarce?
Fermi’s Paradox doesn’t require assuming faster-than-light travel of any kind. It wouldn’t take all that long, relatively speaking (sure, long by a current human lifetime, but short by a star’s), for a consistently expanding sublight civilization to spread through the entire galaxy. The “consistently expanding” thing is the major assumption.
John Barnes wrote a cheery short-short-short story about another possible resolution. One day, all the radio telescopes on Earth suddenly get a signal; it’s definitely organized, repeating over and over for several months or something like that before abruptly ceasing. The signal turns out to be a genetic sequence; labs race to assemble it, which produces a bacteria or virus or somesuch. It is of course heavily quarantined and tested, and appears to do absolutely nothing–it inserts some junk DNA introns that have absolutely no effect on generations of lab mice, that sort of thing.
Over a few decades, the concern about that lags, and quarantine fails. The virus spreads throughout the biosphere, with no effect. A few more years pass, and then one day everything living dies screaming and melting; Earth ends up coated by a kind of universal slime mold, which grows into natural radio transmitters that expend all of its energy into broadcasting its genetic sequence at high power.
Like I said, cheery. Unlikely, but a neat resolution.
TexasSpur, for the purposes of this thread, you may assume we are talking about other species capable of constructing radio telescopes and/or building spaceships able to traverse the distance to the nearest star.
I’ve never been to China, and neither has any member of my family. Why not? You’d think if we existed, at least ONE of us would have gone to China. So, it’s a paradox…if I exist, why haven’t I travelled to China?
A very important issue concerning life-spread is genetic hardwiring. The subject is too complex for my lazy ass to write a thesis here but basically the way our world evolved is based on a predator/prey model. Now that we are ‘civilized’, we have the time to pursue abstract ideas. Chess is a good example. It’s simply a by-product of our predatory evolution skills. Predicting prey stratagies, and formulating ‘plans’ to out-wit them. We certainly did not evolve to play chess.
Conqering the world (or galaxy) is another example of these by-products. But if a lifeform evolved on a world that was more benign, for example (or a million other other scenerios) that lifeform might not have the desire or even curiosity to spread. Instinct is a powerful motivator. Or not!
How would life evolve at all without competitive pressure?
The whole predator/prey thing is based on the fact that it’s easier to assimilate resources that another organism has laboured to produce than it is to produce those resources yourself. I find the non-predator/prey scenario quite unlikely.
But maybe I’m just thinking a bit too narrow here, so feel free to elaborate.
So who’s to say that in a thousand years we won’t have solved the problems of our own planet, and go back to being primarily an agrarian society. Perhaps this “space exploration” thing is just an offshoot of the arms race, and would only evolve on a planet where the most intellegent life form was violent.
I for one, wouldn’t be disappointed if the space program and SETI were suspended indefinitely, and the brightest minds were put to work on environmental, economic, and social problems. Maybe intellegent life evolves out of the “need” to explore space. Perhaps “Star Trek” is a projection of what we wish we could do now, the society of a thousand years from now might just be too busy enjoying life to be bothered with seeking out new life and new civilizations. I hope so.
He (she?) didn’t say no competitive pressure, he (she?) said less competitive pressure.
The problem that many people have (and perhaps Fermi suffered from this, too) is comparing any possible extraterrestrials to our own species/world. Which isn’t exactly a flaw… it’s our only frame of reference. However, one answer to Fermi’s pseudo-paradox (I don’t consider it a real paradox, as the “Why haven’t aliens come here yet?” is NOT an either/or issue) is that perhaps the other intelligent forms of life in the universe just haven’t evolved to the point where their society would be noticeable to us.
Perhaps in a million years, every single star will have a different species inhabiting it, and you couldn’t so much as sneeze (or the galactic equivalent of sneezing) without getting snot (or the galactic equivalent of snot) on someone’s face (or the galactic equivalent of someone’s face).
I take your point SPOOFE and I’m very aware of the pitfalls of thinking inside the box (I’m not always sure how to think outside of it).
From the evolutionary viewpoint, competitive pressure is one of the main driving factors, but the competition is from other life forms, not the environment, even changes in environmental conditions only mean that certain populations are better suited (and can therefore compete more effectively) than others.
Without something to drive it, how is life going to climb the ladder, any competition at all will naturally become fierce competition, and complete lack of competition will become stagnation.
When intelligent life becomes dominant though, maybe it will have a different mentality, but I wonder; it will have had to climb and expand into that position of dominance at the expense of other lifeforms, the urge to expand and take new grouond will be pretty much ingrained.
At least that’s the way my limited mind sees it, maybe there are ways in which intelligent life can come to prevail peacably, but I suspect that competiton is more likely.