Posted on 10/25/2001 9:13:53 AM PDT by RightWhale
Is there obvious proof that we could be alone in the Galaxy? Enrico Fermi thought so -- and he was a pretty smart guy. Might he have been right?
It's been a hundred years since Fermi, an icon of physics, was born (and nearly a half-century since he died). He's best remembered for building a working atomic reactor in a squash court. But in 1950, Fermi made a seemingly innocuous lunchtime remark that has caught and held the attention of every SETI researcher since. (How many luncheon quips have you made with similar consequence?)
The remark came while Fermi was discussing with his mealtime mates the possibility that many sophisticated societies populate the Galaxy. They thought it reasonable to assume that we have a lot of cosmic company. But somewhere between one sentence and the next, Fermi's supple brain realized that if this was true, it implied something profound. If there are really a lot of alien societies, then some of them might have spread out.
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 ten million years, every star system could be brought under the wing of empire. Ten 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?"
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 extraterrestrials 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.
A lot of folks have given this thought. The first thing they note is that the Fermi Paradox is a remarkably strong argument. You can quibble about the speed of alien spacecraft, and whether they can move at 1 percent of the speed of light or 10 percent of the speed of light. It doesn't matter. You can argue about how long it would take for a new star colony to spawn colonies of its own. It still doesn't matter. Any halfway reasonable assumption about how fast colonization could take place still ends up with time scales that are profoundly shorter than the age of the Galaxy. It's like having a heated discussion about whether Spanish ships of the 16th century could heave along at two knots or twenty. Either way they could speedily colonize the Americas.
Consequently, scientists in and out of the SETI community have conjured up other arguments to deal with the conflict between the idea that aliens should be everywhere and our failure (so far) to find them. In the 1980s, dozens of papers were published to address the Fermi Paradox. They considered technical and sociological arguments for why the aliens weren't hanging out nearby. Some even insisted that there was no paradox at all: the reason we don't see evidence of extraterrestrials is because there aren't any.
In our next column, we'll delve into some of the more ingenious musings of those who have tried to understand whether, apart from science fiction, galactic empires could really exist, and what implications this may have for SETI.
For all we know, there could be thousands of old mining traces in our own Belt.
Another point is that maybe they just don't want us to know that they are there for their own reasons. Perhaps we are too primitive to be taken seriously.
Another point is that space travel might not be restricted to speeds that our limited science understands in 2001 AD.
It doesn't do much good to colonize a new planet, only to discover that it has a strain of flu that is 100% fatal.
Civilizations also have a nasty tendency to self-destruct, and species have a tendency to go extinct rather quickly.
It's true we inhabit an ordinary star system in a minor arm of the Milky Way far from downtown. Our star is also in the middle of a vacuum bubble 500 light years across that was cleared out by a supernova sometime back. We're not only living in a rural area, but in a rural area that has been stripped of a lot of natural resources such as interstellar gas of various kinds.
Yeah, whatever. No sane person with even a rudimentary knowledge of physics, much less an expert, could possibly believe something this preposterous.
Actually, contrary to those who think that the speed of light cannot be breached, it can be and has (quite recently in separate lab tests). Fermi's paradox is therefore alive and well.
Carl Sagan believed this and felt that for a civilization to move to a period of galactic or even intergalactic exploration, they must be able to overcome this obstacle that we as a species now face.
Seeing as how we don't have much info on what happened right here on earth even 10,000 years ago, and we have just begun to look around the other planets and asteroids in the solar system, the possibility that others have come and gone many times cannot be denied. Just because we don't see them now doesn't mean they never passed through gobbling up this and that on the way.
Well, don't look here. Beam me up, Scotty.
I agree. We're a "bad neighborhood" to be avoided.
... and ignored all of the evidence packed into government files...
The galaxy is about 100,000 light years across. The speed of light doesn't need to be exceeded to allow for a civilization to spread out and occupy the entire galaxy in 10 million years from GO! Or even 1 million years. Getting to the next galaxy [Andromeda] is a different story.
In 100 years, every nation on this planet will have the ability to destroy all of humanity with ease. There will still be Osama Bin Ladens - I truly doubt that man will ever reach the stars because of these facts.
I believe Sagan was right when he posited that "advanced" civilizations, by definition, will wipe themselves out (long before interstellar travel is achieved).
Like the perfectly square tunnels of South America.
Excellent. You have obviously obtained a copy of The Guide that has Ford Prefect's updated entry for our planet in it.
I was unaware that he had been able to send off his report to Megadodo Publications. Where ever did you get it? =;^)
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