Skip to comments.The Fermi Paradox - Are We Alone in the Universe
Posted on 05/19/2004 12:46:40 PM PDT by Conservomax
Fermi's Paradox (i.e. Where are They?):
The story goes that, one day back on the 1940's, a group of atomic scientists, including the famous Enrico Fermi, were sitting around talking, when the subject turned to extraterrestrial life. Fermi is supposed to have then asked, "So? Where is everybody?" What he meant was: If there are all these billions of planets in the universe that are capable of supporting life, and millions of intelligent species out there, then how come none has visited earth? This has come to be known as The Fermi Paradox.
Fermi realized that any civilization with a modest amount of rocket technology and an immodest amount of imperial incentive could rapidly colonize the entire Galaxy. Within a few million years, every star system could be brought under the wing of empire. A few million years may sound long, but in fact it's quite short compared with the age of the Galaxy, which is roughly ten thousand million years. Colonization of the Milky Way should be a quick exercise.
So what Fermi immediately realized was that the aliens have had more than enough time to pepper the Galaxy with their presence. But looking around, he didn't see any clear indication that they're out and about. This prompted Fermi to ask what was (to him) an obvious question: "where is everybody?"
Also, if one considers the amount of time the Galaxy has been around (over 10 billion years) and the speed of technological advancement in our own culture, then a more relevant point is where are all the super-advanced alien civilizations. Russian astrophysicist Nikolai Kardashev proposed a useful scheme to classify advanced civilizations, he argues that ET would posses one of three levels of technology. A Type I civilization is similar to our own, one that uses the energy resources of a planet. A Type II civilization would use the energy resources of a star, such as a Dyson sphere. A Type III civilization would employ the energy resources of an entire galaxy. A Type III civilization would be easy to detect, even at vast distances.
This sounds a bit silly at first. The fact that aliens don't seem to be walking our planet apparently implies that there are no extraterrestrial anywhere among the vast tracts of the Galaxy. Many researchers consider this to be a radical conclusion to draw from such a simple observation. Surely there is a straightforward explanation for what has become known as the Fermi Paradox. There must be some way to account for our apparent loneliness in a galaxy that we assume is filled with other clever beings.
Bracewell-Von Neumann Probes:
While interstellar distances are vast, perhaps to vast to be conquered by living creatures with finite lifetimes, it should be possible for an advanced civilization to construct self-reproducing, autonomous robots to colonize the Galaxy. The idea of self-reproducing automaton was proposed by mathematician John von Neumann in the 1950's. The idea is that a device could 1) perform tasks in the real world and 2) make copies of itself (like bacteria). The fastest, and cheapest, way to explore and learn about the Galaxy is to construct Bracewell-von Neumann probes. A Bracewell-von Neumann probe is simply a payload that is a self-reproducing automaton with an intelligent program (AI) and plans to build more of itself.
Attached to a basic propulsion system, such as a Bussard RamJet (shown above), such a probe could travel between the stars at a very slow pace. When it reaches a target system, it finds suitable material (like asteroids) and makes copies of itself. Growth of the number of probes would occur exponentially and the Galaxy could be explored in 4 million years. While this time span seems long compared to the age of human civilization, remember the Galaxy is over 10 billion years old and any past extraterrestrial civilization could have explored the Galaxy 250 times over.
Thus, the question arises, if it so easy to build Bracewell-Von Neumann probes, and they has been so much time in the past, where are the aliens or at least evidence of their past explorations (old probes). So Fermi Paradox becomes not only where are They, but why can we not hear Them and where are their Bracewell-von Neumann probes?
Possible solutions to Fermi's Paradox fall in the following categories:
In general, solutions to Fermi's paradox come down to either 1) life is difficult to start and evolve (either hard for the process or hard to find the right conditions) or 2) advanced civilizations destroy themselves on short timescales. In other words, this is an important problem to solve in the hope that it is 1 and not 2.
No aliens? I want a DNA test from James Carville! :)
But seriously, thanks for posting. I will read in more detail as soon as I get a chance.
Berserkers: The Galaxy is filled with killer robots looking for signals. ET is keeping low. Problem: where are the berserkers coming after us?
That's the Borg - they aren't here yet.
In the article, the author postulates that if aliens exist we should be overrun by probes by now. The rebuttal to that is that either they have different methods of probing than we have come up with (hey, they're aliens, they think differently), or, like ours would be, theirs are small enough that we have never noticed one (it might not have come close enough to us to be recognized).
Just thought I'd throw that in. I tend to think it is a combination of distance and incomprehensibility that has kept us from detecting/recognizing our neighbors.
We should build a Dyson Sphere. It might take 100,000 years, and it might take more engineering knowhow than we currently would consider possible to attain, but I think we could eventually do it. We're humans - solving impossible problems is what we do best. Bickering over little problems is what we do when we're not solving impossible ones.
Read it before and I think that it's combinations of
Planets With the Right Conditions are Rare
Planetary systems are rare
Habitable zones, proper distance from star for liquid water, are narrow
Galaxy is a dangerous place (gamma-ray bursters, asteroid impacts, etc)
Earth/Moon system is unique (large tides needed for molecular evolution)
Life Is Rare
Life's Genesis is rare
Intelligence/Tool-Making is rare
Language is unique to humans
Technology/Science is not inevitable
AND a third thing, we are still assuming that life is like terrestrial life.
If a being has no eyes, doesn't see the stars, can't imagine another world beyond the limits of his own, why would he try to go beyond it?
And that's an EASY example.
Well of course not, we don't make first contact until 2063...
"The surest sign that intelligent life exists elsewhere in the universe is that it hasn't tried to contact us." -- Calvin
Sometimes the best wisdom comes from a comic strip.
At any rate, perhaps the rest of the universe is still trying to determine if there is actually intelligent life on this planet. One could have difficulty determining that if they were assessing the ape logic found in the major media outlets.
Very good diagrams.
One week the question was "Is there intelligent life on earth?"
On the Friday of that week as I passed it I noticed that someone had scrawled an answer right below the question: "Yes but we're only visiting"
That was my nearest contact with extra-terrestrials
Is it possible that any society smart enough not to destroy itself would be smart enough not to construct Bracewell-von Neumann probes? I'm thinking Star Trek I here, folks.
Oh, and by the way... Once we reach step 2, I'd argue it would be fairly impossible to exterminate ourselves. The window for an intelligent race to annaihilate itself seems rather small for me. BUT! There are other means of population containment besides self-annaihilation. In certain regions of Europe, medieval civilizations avoided overpopulation by the development of a large celibate class. In England, for instance, this led to 3 centuries of peace, and life expectancies that would not again be reached until the 20th century. Fermi seems to believe that population dynamics of intelligent races mimic those of bacteria. (There are arguments for this... It takes only one dissident planet to start populating the galaxy, and this would have to take place among the outer planets -- the most likely to be dissident.)
Because of the distances and energies involved. The Fermi Paradox is pure codswallop IMHO.
Of course another possibility is that a "colonization" took the form of genetic seeding of planets. In that case the answer to Fermi's question would be "You're looking at them".
Hah. No, I didn't even notice that, had I, I would have changed it to greens.
Fermi Paradox Redux
I had a personal interest in studying the origin of life when I was in college. At the Smithsonian, I plugged my (admittedly fantastically subjective) guesses into their Fermi computer. Know how many intelligent races my guesses predicted in the universe? 2.
Fermi's dilemma present evidence for their not being *hordes* of intelligent races. If there are a relatively small number, which evolved only, say, on 3rd-generation (and therefore, recent) stars, we could be outside of each other's "cone of light."
The "cone of light" refers to the area that can be travelled to within the Universe (presuming the speed of light as maximum speed). Since much of the Universe is speeding away from us at just about the speed of light, the area of the cone of light is finite, and less than the area of the Universe (OK, "volume" is the correct term here, not "area"). Since, over time, this area grows steadily larger as time progresses away from the point of origin, the area appears conical when plotted in a 4th dimension chart.
My 2 cents. We'll never leave the solar system without knowledge / use of time travel.
Strapping ourselves to an oversized party favor (rocket)won't get us too far.
We'd be better served trying to learn how to travel between different dimensions.
I tend to go along with resolution III "They do not exist". I like to think that, in a sense, Adam and Eve were meant to colonize the universe, but unfortunately for us, they screwed the pooch (to borrow a phrase from "The Right Stuff").
Lack of "money". It's expensive to travel throughout the Galaxy.
Schrodinger's Cat Litter in the large box,
at all locations, simultaneously...
Actually, It will probably be the only way for a while. The paradox states taht Intelligent life would take several hundred thousand years to colonize the galaxy.
They also used the incorrect form of 'too'.
'While interstellar distances are vast, perhaps to vast to be conquered by living creatures with finite lifetimes'
grrr, that one makes me nuts.
Bump for later pondering.
"Takes only one ET to break embargo."
Hmmm... aliens *normally* don't wish to communicate with us, but occasionally break an embargo. Explains why:
* Despite their mastery of the universe, the aliens who actually do contact Earth are such lousy pilots as to crash into Roswell, etc. They prolly stole a spacecraft thinking it looked easy to fly.
* Only aliens to break embargo are socially deviant... explains why they seem so fascinated with rectal probes.
* They seem to prefer areas filled with other deviants.
...i caught that.....
The Krell Theory (from "Forbidden Planet"). Technology evolves to the point where any insane individual can wipe out civilization on a whim.
The Type-13 Planet Theory (from "Lexx"). Technology advances until an experiment in a high-energy physics lab damages the fabric of space-time and causes the planet to contract to an ultradense object the size of a pea.
The Lyekka Theory (also from "Lexx"). Like the "killer robot" theory, but a civilization's radio signals are heard by beings who are not evil but simply looking for yummy planets with lots of tasty things.
The Rub is in the replication process and creating enough delta-V to not only escape the surface of the planet/moon used for replication, but also the star that planet/moon is in.
Since we have been radiating narrowband EM into space for only a short time, why do you think anyone even knows we exist?
If there are well-advanced civilizations "out there," we are barbarians compared to them. And when I look at the 20th Century history of wars on Earth, I'm inclined to agree with that assessment. And if that is the view, it would make absolute sense for THEM to steer clear of US until we GROW UP.
Yes, we do. And now that you've discovered our secret, we have to kill you.
Aliens have go one to other dimensions, or have transfered themselves to a computer simulated universe ("Matrix").
The Cone of Light would function between galactic clusters, but not within the local galactic cluster. Within the local galactic cluster there would be no way to travel intergalactically since no power source, including nuclear, would last the several million years needed to make the trip. We might populate the Milky Way were it not for Congress, but we wouldn't ever go beyond the Milky Way.
correction: Aliens have gone on to...
This would be the "we are the last ones to leave the party" scenerio.
This is sort of the correct answer, I believe, although I think of it as the Gray Goo Solution. There's much more room at the bottom than there is at the top. As civilizations progress, the timescale that is relevant to the society gets ever shorter. Because of the speed of light limitation, this means that the relevant distance scale gets ever shorter. There's nothing to do but shrink.
Dangerous Particle Physics
LOL, someone should ban this before it's too late!
Nope. Berserkers were Fred Saberhagen's idea.
Scenario IV: They exist but are all Democrats, and thus cannot get anything done on their own planet, let alone communicate with us.
So, from an arrogant, Earth/human-centric point of view of the Milky Way Galaxy, there has been no other development of intelligence in the Milky Way Galaxy at least as of 80,000 years ago.
Which is Bush's fault. But the aliens do manage to show up in droves every election to vote Demorat.
Exactly. Nobody would go for economic reasons, unless something is out there that's so unique that a) it couldn't be replicated at home and b) that it's worth making a trip to go get it.
No, nobody is going for economic reasons. If there's any reason to go, it'll be for political and/or religious reasons. And people that are comfortable with where they are won't leave, so that leaves the dissidents/persecuted. And it's a lot cheaper to simply kill them all instead of paying out lots of money to ship them off somewhere else if they're proving to be too much of a problem.
The only plausible way anybody's going is if there's absolutely no other choice, say like living conditions on the homeworld becoming untenable.