[MeekOneGOP]

EXCELLENT article. "Live long and prosper", fellow FReepers!

[Darth Reagan]

38 generations of colonists are required to bring the entire Galaxy under control.

Assuming the alien generation is as long as ours, this would take about 1200 years. If the galaxy is about 12 billion years old (if may be 15, or more), then that's only 0.00001% of history. Not much. Consider what Earth would be like today if civilization started only 5,000 years earlier than we did. We'd have been to the moon by the time the Egyptians built the Pyramids in our timeline. Imagine where we'd be today.

[A Vast RightWing Conspirator]

Perhaps the evidence of alien presence is so beyond us that we simply don’t recognize it (somewhat like mice in The Louvre checking out the Mona Lisa).

Right, something like the 'big bang' or spiral-shaped galaxies.

[PatrickHenry]

SETI ping.

[okie_tech]

I have another hypothosis that is rarely proffered. What if we are the first or the only current advanced civilization? Someone has to be first. The odds are against it but at least it fits the available facts. What if the Universe is just too dangerous a place for any single civilization to last very long? Note that we always look for alien life via radio but our own age of radio is rapidly waning. Electromagnetic signal propogation may be completely obsolete in only another hundred years time (I like to envision communications based on quantum entanglement but I don't know if entanglement degrades over time and what that time might be, any physicists out there?), which would leave us with only 200 odd years of radio signals spreading out through the galaxy. That doesn't even count as a blink in cosmic time. The odds would seem to be against any other civilization hearing that little blink unless two civilization were at the same or similar stage of development at the exact same time minus/plus the distance/time for the signal to reach from A to B. Pretty bad odds of that happening. I happen to believe that life may be common but that civilization is extremely rare and fragile. Colonies may be established but a true galactic civilization would seem to be out of the realm of possibility.

[mvscal]

It's only a paradox if there actually are "advanced extraterrestrials". Personally, I don't think that's a given. I have no problem believing that the galaxy is teeming with life, but advanced space faring life is another ball of wax entirely.

[John Jorsett]

Maybe when a race reaches a level of technology in which it can construct completely realistic virtual realities to inhabit, it loses the desire to conquer physical reality. I see signs of this already. Many of the players of Everquest and such games completely lose themselves in them, to the near-exclusion of all else in their lives, and that's just with the crude technology we have right now. If civilization were sufficiently advanced that they could transfer their consciousnesses into the virtual worlds they love so much, I have no doubt that many if not most of them would do so, and effectively vanish from ours.

[lotus]

Civilization only progresses directly to it's ability to destroy it's self. When that point is reached it's gone.

Therefore, none wil exist much more advanced than us and to look in areas older than us is useless. Only new star systems should be looked at, but unfortunately, I think they look for more advanced older systems.

[splint]

Nothing is impossible. I think, therefore, I am. The best way to travel from galaxy to galaxy is by PURE THOUGHT! By the way, when's the next comet suppose to be here? I need to hitch a ride.....

[Congressman Billybob]

The article refers to, but does not quote, the Fermi Paradox. Enrico Fermi, a great scientist and philosopher, was conflonted with the fact that there are (in Carl Sagon's words) "billions and billions of stars (and planets)." some capable of supporting life and billions of years older than Earth.

Presumably, some of them would have developed space travel, and with all those options, at least one of those alien races should have "discovered" Earth, since the envelope of our electronic spectrum, showing that we are hear, now reaches beyond Alpha Centuri. Fermi's response was, "So, why are they not here?"

The anser may be found in the first law of the Federation in Star Trek, which is "non-interference." We would be to these space travelers as primative as head hunters in Boreo are to us. The simplest explanation is that they are there, they know we are here, but they are leaving us alone until we become sufficiently civilized to be invited to join the Federation.

"The simplest explanation that is consistent with the facts is most likely the correct one." Occam's Razor.

Conressman Billybob

[sadamico]

Bumped for later read.

[lds23]

Maybe all these other planets have leftist governments, who say it wouldn't be fair for anyone to go to another planet until everyone could.

[Stefan Stackhouse]

Then there is CS Lewis's hypothesis: There may be others out there, but if they are, then they -- unlike us -- may not be fallen. God may have arranged things in such a way that Earth is under a sort of cosmic quarantine. If we came into contact with them, the inevitable result would only be bad news for them.

[Physicist]

One possible explanation is that interstellar travel is just too costly. Consider how expensive it would be for us to populate another star system. Imagine sending a small rocket to Alpha Centauri, one that’s the size of the Mayflower (180 tons, with 102 pilgrims on board). Your intention is to get this modest interstellar ark to our nearest stellar neighbor in 50 years, which requires about 150 billion billion joules of energy.

Let's check this. The mass of 180 tons is 180,000 kilograms. The velocity given is 8% of the speed of light, and the speed of light is 3x10⁸ m/s. Kinetic energy is 1/2 m v², but we can double the energy expenditure because of deceleration. So the total energy, in joules, is 6.4x10^-3 times 9x10¹⁶ times 1.8x10⁵ = 1.04x10²⁰, or about 100 billion billion joules. Close enough.

The problem is that the fuel and propellant required to decelerate that mass is gigantically large compared to 180 tons. But that mass must also be accelerated to that speed (and for the most part, decelerated). So that requires an amount of fuel and propellant that is again gigantically large compared to the fuel and propellant I already named. These aren't part of the author's energy budget.

Then there's the question of whether 180 tons of stuff can keep 102 people alive for 50 years. If the Mayflower took that long to cross the ocean, it wouldn't have bothered setting out. It's not just an expensive proposition; the equations don't admit of a solution.

[varon]

One possible explanation is that interstellar travel is just too costly.

Typical human response. Who is to say that if "life/civilizations" existed elsewhere that they would know of or have an economic or monetary system.
Even here on earth we have many examples of "civilizations" existing and functioning without money or other economic concepts.....bees, ants etc. These creatures exist and accomplish everything necessary to fulfill their lives without an ATM machine. How refreshing.

[Junior]

I have my own theory -- the "nanny bureaucracy hypothesis." Any advanced civilization will never reach the stars because:

(a) It costs too much and the money would better be spent on shopping carts for the homeless; and

(b) It's just too dangerous. Someone might get hurt.

[MeekOneGOP]

Pings for good FReepers!

[<1/1,000,000th%]

They're all busy at home fighting terrorism and playing video games.

[Paul C. Jesup]

Ladies and Gentlemen, what you all have got to understand is that there a three very good logicial explainations as to why no aliens have contacted us. The three are:

The first is the fact that our solar system is locate at the very edge of the Milky Way Galaxy. In other words, we are so far in the back woods, that it would not be worth contacting us.

This is also the reason why I think we have not recieved in alien broadcasts. Or we may have recieved some alien broadcasts and thought is was just static because their forms of data encryption and data compression are to alien for us to understand.

The second is the fact that they would have to go through two asteroid fields to get to our planet, Earth. The first is the asteroid field that is right past Pluto. Then they would have to cross the asteroid field between Mars and Jupiter.

The third is that from what we understand, Earth has no real special resources to speak of. Also, if any aliens recieving our, radio, televsion and internet broadcasts: They would think the human race was completely insane. Which they maybe questionably right.

So what alien race would want to come to a planet that they would consider to far and to difficult to get to, with no special resources to speak of and forced to deal with a species they consider completely insane.

Considering all that I have just stayed, I would think twice before wanting to go to Earth.

[JoeSchem]

The Bible states that man has a special place in God's creation, ". . . a little lower than angels." If there's life on other worlds, it originally came from Earth.

The Cydonia Files

[HENRYADAMS]

Maybe we are it? Since many are so fond of "evidence" give us the "evidence" of other civilizations around other stars.