Posted on 05/19/2004 12:46:40 PM PDT by Conservomax
Fermi's ParadoxFermi'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.
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Hah. No, I didn't even notice that, had I, I would have changed it to greens.
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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.
Congressman Billybob
Latest column, "Congressmen, Humorists, Burglars -- All of Us in the Trade."
Yes, we do. And now that you've discovered our secret, we have to kill you.
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