The Fermi Paradox - Are We Alone in the Universe

[Fitzcarraldo]

Aliens have go one to other dimensions, or have transfered themselves to a computer simulated universe ("Matrix").

[RightWhale]

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.

[Fitzcarraldo]

correction: Aliens have gone on to...

[Fitzcarraldo]

This would be the "we are the last ones to leave the party" scenerio.

[Physicist]

Nanobots -> Gray Goo Problem

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!

[brbethke]

That's the Borg - they aren't here yet.

Nope. Berserkers were Fred Saberhagen's idea.

[Still Thinking]

Scenario IV: They exist but are all Democrats, and thus cannot get anything done on their own planet, let alone communicate with us.

[xrp]

Not to mention that, assuming what we regard as a path of evolution, intelligent species at some point use radio waves to communicate with each other, if any other intelligent species developed in the last 80,000 years in the Milky Way (since no point in the Milky Way is more than 80,000 light years from Earth), we would have detected them because of their radio waves.

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.

[talleyman]

Lack of "money". It's expensive to travel throughout the Galaxy.

Which is Bush's fault. But the aliens do manage to show up in droves every election to vote Demorat.

[adx]

Lack of "money". It's expensive to travel throughout the Galaxy.

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.

[Still Thinking]

Dangerous Particle Physics. LOL, someone should ban this before it's too late!

When Dangerous Particle Physics are outlawed, only Dangerous Particle Physicians will have... Oh, never mind!

[Little Ray]

How 'bout they all "trancended."
That's another way of saying that they uploaded themselves and are are busy playing Quake X^nth and other advanced VR games. They have no incentive to go out and be imperialists - real life isn't as much fun as VR and they don't need much in the way of resources.

[RightWhale]

The other point is that galactic civilizations may arise, but they may also burn out. There may have been dozens of civilizations pass through the Solar System in the past millions of years, but none are here now. It is possible we are the remnant of one of the latest ones to pass through.

[Little Ray]

Transcended. Sheesh. Need to learn the to use the spell checker.

[Little Ray]

Transcended. Sheesh. Need to learn the to use the spell checker.

[Little Ray]

Transcended. Sheesh. Need to learn the to use the spell checker.

[xrp]

We should build a Dyson Sphere.

Where do you plan to get the materials for the Dyson Sphere? :-)

There isn't enough matter in the solar system, outside of mining the sun, to construct one.

[ZULU]

One more possible solution.

They have seen the earth and how we behave and have no desire to visit here.

I think the vast distances involved would preclude travel even by robots.

The closest star is several light-years away, and not every star has planets. Of those stars which DO have a planet system, very few of them may possess a system capable of sustaining earth. Not only would a life-sustaining planet have to be the proper distance from its star, it would also have to have a moon like ours. The moon provides the earth with some kind of astrophysically essential ingredient for the existence of life which I can't recall.

Also, we are not sure that evolution on those few planets that may be capable of sustaining life progressed to the level of intellignet life. Intelligent life as we define it, may be a rare or non-existant trait in other worlds.

[Constitution Day]

BTTT, read later.

[Gorjus]

This is essentially a mathematics problem, with a lot of estimated values. However, even if you use very low probabilities for the various factors (probability of a planet in the liquid-water zone, etc.) you still get a very large number of should-be-inhabited planets when you multiply it by the total number of stars - very likely enough that we should see evidence of them. So another way to formulate the question is: What forces the various factors low enough that we don't see any evidence of extra-terrestrial life?

There was a science-fact article on that several years ago in Analog. They said the formulation is missing a key factor - what is the probability that a 'stubborn' species would develop?

The article examined the physical characteristics of man, and what that meant for an evolutionary niche. I won't go into all the evidence, but the result of being two-legged, with disproportionately large lungs, and better heat rejection (sweat) than other animals is that man is adapted to be a 'cursorial hunter.' That is a hunter who runs doggedly (a descriptor derived from the other known cursorial hunter) after a prey until the prey is worn down and can be killed.

To succees at that, the cursorial hunter has to be stubborn - unwilling to give up until the prey is worn out. The expression, "If at first you don't succeed, try, try again" is uniquely applicable to stubborn hunters. In contrast, Tony the Tiger's attitude is, "If at first you don't succeed, to hell with it."

Building a technical civilization takes heaps of stubborn. As Edison said, "Genius is 1% inspiration and 99% perspiration."

So, if you take the calculation of likely civilizations and add another factor that requires the sort of environment - wide, flat, reasonably dry plains with good lines of sight to keep an eye on the prey - you can drop the likelihood of another technological civilization down low enough that it's unlikely we'd see evidence of them, even if all the other factors are reasonable.

I'm not trying to 'prove' that analysis of Fermi's paradox, though the logic of man as a cursorial hunter was compelling.