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.
Good idea. We can start making a list. it's hard to know what should be near the top of the list, but the motives of our American ancestors who emigrated from Europe [ and other continents as well] might be dredged up.
Or like Daniel Boone, maybe some elbow room is called for:
-- When I moved here this valley was quiet. Now I can see the smoke from my neighbor's chimbley. Time to move on.
Or any of a lengthy list of persons seeking relief from religious persecution, which might include Christians these days, both nominal and practicing.
Or young people who see their future on earth somewhat constrained by overpopulation and excessive regulation.
Like that. God gave us feet, and we use the heck out of them, always have.
"There were other civilizations. But one-by-one, their liberals destroyed them."
"CS Lewis addressed this question both in his Space Trilogy and in an essay. His hypothesis is that God could have created many different sentient beings, but because of the Fall, earth is "quarantined" and thus out of contact."
If it is unintentional we won't see it. Think of the power levels required to be detectable for any practical volume of space.
Is this a new definition of evolution? Is there no extinction or is it all extinction?
This is where you are mistaken. The narrow band detection approach provides a dramatic boost in the signal-to-noise ratio. If they are radiating, we should eventually detect them. I have not tied up hundreds of thousands of dollars of equipment for a search that could never have the possibility of finding anything.
I think a technologically advanced enough race to have conquered star travel would be able to far easier create artificial lips than to expend the energy to travel light years to get them. :)
Physicist is correct (kinda) ... in more ways than has been said. Old Albert did not take into consideration externally derived / accumulated energies in his famous (and erroneous) equation(s) especially pertaining to gravitational amplification / negation. He also did not examine several other possible extra-dimensional / resonate frequency possiblities though Tesla did (in a round about way)
Warp engines? They may never exist. I beleive it wont be an engine at all. They will generate or find a window that one enters or steps into where it would only takes seconds to cross the galaxy. Sort of bending time and space. Like taking a long narrow rug and pushing two ends together and just stepping across from one end to the other end.
What is the signal strength of an omnidirectional one megawatt signal at 4.5 light years?
Ah, but who would care about the cost? Think of the adventure! What it all boils down to is this: if the technology exists, and is relatively affordable, all kinds of amazing things will happen, even if it's just for fun or national prestiege.
Besides, who says the assault force needs to come back home? They just need to take over the conquered world and stay there. Cuts the travel cost and transit time in half. Those who will pay the bills for the expedition will surely understand that any new settlement requires a lot of investment before it starts to pay off. These things take time. If the technology for the journey and conquest exist, the jihad (against the evil ones of the mucus empire) will not be long in coming.
Well if thats the case I can't stop them. However a SETI search will not have any effect on us being visited or not. :)
It depends on the bandwidth and other factors of the signal. Here is a web page that describes the feasibility of detection of an extra solar signal:
http://www.faqs.org/faqs/astronomy/faq/part6/section-12.html
Any antenna modification ideas?
Sorry, I should have attributed it. I thought the blockquote and italics were sufficient to indicate that it was a quote. It's from the science fiction story "The Shores of Bohemia" by Bruce Sterling. I highly recommend it. It's about how nanotechnology puts the political shoe on the other foot: the bourgeoisie capitalists go back to nature and the hippie communists struggle to preserve industrial society.
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