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Our Galaxy Should Be Teeming With Civilizations, But Where Are They?
Project Phoenix ^ | 25 Oct 01 | Seth Shostak

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.


TOPICS: Culture/Society; Editorial; Extended News
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To: cookcounty
The "scientists" that promote SETI do so out of RELIGIOUS desire, NOT because of "science."

Maybe some do. But not all. Some are simply grownup radio amateurs who like to tinker with radios.

201 posted on 10/25/2001 5:14:27 PM PDT by RightWhale
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To: theoutsideman
Every living thing in the entire universe is right here upon the Earth where God created it. Simple, is it not?

And how do you know this?

202 posted on 10/25/2001 5:15:10 PM PDT by RadioAstronomer
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To: headsonpikes
Ya. Fortunately, mine's based on "I HAVE THE MAGIC BUNNY EARS!"
203 posted on 10/25/2001 5:15:53 PM PDT by Psycho_Bunny
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To: cookcounty
The Saganites are good entertainment, though.

I know I have posted this before but one of my more interesting privileges was to be interviewed on the same TLC program that featured Carl Sagan also.

204 posted on 10/25/2001 5:18:15 PM PDT by RadioAstronomer
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To: Psycho_Bunny
I'll take your word for it! LOL!

Mine has a ...different...foundation.

205 posted on 10/25/2001 5:19:10 PM PDT by headsonpikes
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To: cookcounty
If we don't know how life began on earth, how can we possibly make statements about the probabilities that it has arisen elsewhere.

Probability. There are so many stars, with (more than likely) so many planets that the odds against there being other inhabited planets are, well, astronomical. Of course then you multiply that by the number of galaxies nad it get's rediculous. Even from a strictly Christian perspective it's just plain unlikely that God would go through all the trouble of putting all that stuff out there and only put life on one out of the way rock.

206 posted on 10/25/2001 5:20:31 PM PDT by discostu
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To: RadioAstronomer
Who is Bob Lazaar?
207 posted on 10/25/2001 5:21:06 PM PDT by mlo
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To: RadioAstronomer
The problem is I don't think we have been taking random samples. We have concentrated all our eggs in one basket so to speak. The 21cm band. This is why my search is at a frequency range that is about 4 times higher at around 4Ghz.

I read a recent article on SETI that suggested that the sun is actually at distance from the center of the galaxy that optimizes the chance of life. It went on to say that stars in the outer bounds of the MW are older and have the right mix of metals, carbon and the like to foster life. The implication was that other planets conductive to life are likely to be in or near our orbit around the nucleus of the MW. Another thing the article said was that the center of the MW is too active with young stars to hold life. Does that many any sense?

208 posted on 10/25/2001 5:21:43 PM PDT by WRhine
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To: RadioAstronomer
I've known it all along. You may search all you wish, but it will be futile. And, if I had my way, taxpayers would not send a penny to SETI type operations. They are just pure bunk and we all ready have enough of that in Washington.
209 posted on 10/25/2001 5:22:31 PM PDT by theoutsideman
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To: theoutsideman
Every living thing in the entire universe is right here upon the Earth where God created it. Simple, is it not?

Simple, and yet not simple. Either we are alone in the universe or we are not. Whichever option you choose to evaluate leads quickly to awesome conclusions. The God option brings a lot of responsibility with it, and is possibly more complex than the Sagan option.

It's possibly more complex in this way: If we are God's only creation, we have a lot of growing up to do, a lot more than just trying to qualify for membership in some Galactic Federation. At this time it appears that we are alone in the galaxy at least.

210 posted on 10/25/2001 5:23:40 PM PDT by RightWhale
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To: mlo
Who is Bob Lazaar?

A person who (in the UFO circles) claims to have seen alien space craft being reversed engineered in area 51.

211 posted on 10/25/2001 5:25:19 PM PDT by RadioAstronomer
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To: WRhine
Does that many any sense?

Opps--Should read: Does that Make any sense?

212 posted on 10/25/2001 5:25:23 PM PDT by WRhine
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To: RightWhale
It's sad to think that Humans might be the most advanced form of life in the galaxy...
213 posted on 10/25/2001 5:26:00 PM PDT by xm177e2
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To: RadioAstronomer
The beam width of my antenna covers about 1.7 degrees.

We had a colloquium yesterday that discussed a proposed X-ray telescope called MAXIM. One of the purposes of MAXIM is to image the event horizons of black holes at the centers of distant galaxies. The required angular resolution is of order a few micro-arcseconds. Incidentally, it would also be capable of imaging planets, and surface features on distant stars!

214 posted on 10/25/2001 5:26:22 PM PDT by Physicist
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To: discostu
Have you heard this: some people believe or used to believe that God created 196,000 earths before this one and it took that many to get it right.
215 posted on 10/25/2001 5:26:22 PM PDT by RightWhale
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To: discostu
Even from a strictly Christian perspective it's just plain unlikely that God would go through all the trouble of putting all that stuff out there and only put life on one out of the way rock.

Even if he did put life on just one planet, the chances of the living material being scattered throughout the Cosmos are great after millions of years. This would be done via collisions with asteroids, comets, etc.

216 posted on 10/25/2001 5:26:38 PM PDT by Joe Hadenuf
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To: theoutsideman
I've known it all along. You may search all you wish, but it will be futile. And, if I had my way, taxpayers would not send a penny to SETI type operations. They are just pure bunk and we all ready have enough of that in Washington.

I'm glad you know this. I sure don't. Also my search has used no government money. It is a privately funded effort.

217 posted on 10/25/2001 5:28:42 PM PDT by RadioAstronomer
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To: discostu
Taking a cosmological centrist view (ie, that we are a typical race on a typical planet in a typical solar system) then the majority of other possible civilizations are no closer to regular space travel than we are, some are farther some are closer, but most are at roughly the same point on their "trip to the stars" as we are.

The problem with this view is that it almost assumes that technological improvement is a linear or sublinear curve, when in fact it is exponential.

This is something to think about very careful. Let's assume an absurdly narrow window of all the civilizations in our galaxy starting within 100,000 years of each other. Let's also make the absurd assumption that technology in all these civilizations grows at exactly the same pace. Even with these assumptions, the truth of the matter is that a civilization technologically only 200 years ahead of us will effectively have god-like powers from our perspective today. The difference between now and 10,000 years of technological advancement is so great that it isn't even imaginable. So even if we were the average civilization in the local neighborhood, we should see the galaxy swarming with species of unimaginable power, the guys on the right-hand side of the technological bell curve.

But we don't see that. This leads to a few possible conclusions, most of which you'll probably find distasteful. One, we could be the most advanced civilization in the universe. Someone has to be it, but it seems improbable because a lot of civilizations could've had an earlier start by at least a few billion years. Second, there are no other civilizations. Third, all the other civilizations have died. Fourth, the only other existing civilizations haven't generated evidence within our lightcone. I can offer a few more, some of which are far more probable than some of the ones I listed here, but they open up their own can of worms.

218 posted on 10/25/2001 5:29:49 PM PDT by tortoise
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To: Physicist
We had a colloquium yesterday that discussed a proposed X-ray telescope called MAXIM. One of the purposes of MAXIM is to image the event horizons of black holes at the centers of distant galaxies. The required angular resolution is of order a few micro-arcseconds. Incidentally, it would also be capable of imaging planets, and surface features on distant stars!

We could learn a great deal from this. I just hope it doesn't go the way of the SSC. Sigh!

219 posted on 10/25/2001 5:30:59 PM PDT by RadioAstronomer
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To: RadioAstronomer
A person who (in the UFO circles) claims to have seen alien space craft being reversed engineered in area 51.

Why did you know that?

just kidding :)

220 posted on 10/25/2001 5:31:36 PM PDT by mlo
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