Fermi's Paradox II: What's Blocking Galactic Civilization? Or Are We Just Blind To It?

Space.com ^ | November 8, 2001 | By Seth Shostak, Astronomer, Project Phoenix, SPACE.com

[biblewonk]

Wouldn't a radio signal be pretty faint by the time it traveled even as little as 4.3 light years?

[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.

[MeekOneGOP]

Thanks for your interesting post, CB! Here are some links related to your observation:

Fermi's Paradox

Google Search for "Fermi's Paradox" Related Articles

[balrog666]

Maybe when a race reaches a level of technology in which it can construct completely realistic virtual realities to inhabit...

Maybe when a race reaches a level of civilization beyond mere survival, it allows the rise of liberal thinking that will eventually drag it back down to the mud.

[discostu]

But, you have to add time for the civilization to go from cavemen to that level of technology, which from what we're seeing is pretty long. And you have to assume they develop alone, uncontested (all spread times increase dramatically, possibly to the infinite when contested). And you have to assume they even want to colonize continuously until conquering the entire galaxy. Then finally you have to assume that either we have the technology to detect them, or they decided to communicate with us on our level of tech.

There are actually more assumptions in the "alone in the galaxy" arguement than in the "there's somebody else out there" position.

[adx]

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.

Yup. Here's a theory for you: any sufficiently advanced civilization will eventually spawn liberal infestations, who will likely succeed in dragging the civilization back down the ladder of progress. :)

[discostu]

Too true, and it's a bad habit. To ensure survival a species MUST expand off the planet (and eventually out of the galaxy all together), eventually the planet (which ever) will no longer sustain, if nothing else the sun that the planet revolves around will either blow up or go out, any species still rock bound at that point was a complete waste of time (nudge nudge all you space exploration opposers).

[headsonpikes]

"Since there is no evidence of intelligent life.(including here on Earth.;-)

Occam's Barber shop--two chairs, no waiting!

[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.

[discostu]

Nope, the Occam's Razor conclusion runs like this:
We have to go off of the evidence we have, assuming other species are significantly more or less advanced than ours is contrary to the available evidence.
Our detectable (communications) technology has only reached out to Alpha Cen (a little past but not to any other stars).
Our detection technology (again communications) is entirely hinged upon: A - when the other species developed the technology in relation to how far away from us they are (a civilization 4000 light years away won't be detectable until 4000 years AFTER they invent radio, and of course if their radio communications went past us (assuming they moved past that technology) before we invented the radio we're doubly SOL); and B - them using the same subsection of the carrier wave spectrum we do (that right there is highly improbable if based on random chance since we only use about 10% of the spectrum).
Therefore the simple solution is that our footprint is so small (only 1 other star) that nobody has noticed us, and that our "spotlight" we're aiming at the galaxy is so miniscule in detection width and penetration deapth that we're lucky we've managed to spot ourselves.

[discostu]

Cost doesn't have to be dollars. Cost as a concept originated around resources, not money. Energy has to come from something. Given our current methods of travel in space we'd have to pretty much empty ANWR to get anywhere with a ship large enough to carry enough people to make a colony (which, because of recessive gene traits in breeding populations would actually have to be a lot of people if they were to be stand alone and not repopulated from Earth in a few generations, and they'd have to be stand alone because it would take a couple hundred years to get anywhere). That's a lot of cost.

[MeekOneGOP]

Pings for good FReepers!

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

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

[steve-b]

Then there's the question of whether 180 tons of stuff can keep 102 people alive for 50 years.

The problem of building a closed ecology is tough, but not insoluble in principle (though it probably would require rather more than a ton and a half of mass per person). Once that problem is solved, accelerating an "interstellar ark" to a speed that will get it to a nearby star before something critical gives out (i.e. a few percent of c) is also tough but not insoluble.

My favorite solution to the Fermi Paradox is the theory that, life inside the closed ecology becomes the "new normalcy" and that arks arriving at a new system just aren't all that interested in it except as a subject of scientific study and a source of raw materials (for the latter, asteroids and comets are easier than planets, if you're out in space to begin with). Thus, systems get visited but not colonized (at most, there would be the occasional long stop to build new arks when the old one gets too crowded or worn out).

[Licensed-To-Carry]

I believe you are correct.

We are it, there aren't any other advanced life forms. I suspect alien algae is our most highly developed universal neighbor.

[js1138]

But, you have to add time for the civilization to go from cavemen to that level of technology, which from what we're seeing is pretty long.

It didn't take us long. About 8000 years from the end of the last ice age to the present -- more than half of which is recorded in written history.

An a species only has to do this once. The colonists will have their past to build on.

If we assume that colonization proceeds at small fraction of the speed of light, the technological advances made by the home planet will always be available through ordinary radio transmission.

So even if the colonists hibernate during travel, they will wake up to knowledge that advanced while they were asleep.

[varon]

Cost doesn't have to be dollars.

My remark was referencing other civilizations in our or other galaxies. Who is to say that the concept of cost exists elsewhere if other civilizations exist?

[Fiddlstix]

Wouldn't a radio signal be pretty faint by the time it traveled even as little as 4.3 light years?

Good Point.

[garyhope]

I think you may be right, We could be alone. It's 50/50 isn't it? Everything is 50/50 isn't it. Life is binary. Everything is binary.

The mechanics and logistics of space travel are very daunting. It's a VERY long way to the next place and we may not be able to get there from here. There's no Denny's on the way.

My "touchy feely" new age friends do not want to hear this. Many people want to, need to believe in the magic or other powers or something else other than the absolute banality and mundane ness of their lives and life on our pretty little planet. If there is no one else in the universe, it means we have to take total responsibility for our lives and all our decisions and actions on the planet. There's no one else or thing to blame anything on. It's much easier for some when they have an out. Victim hood is easier. Many are afraid that this is it. Short, sweet and a one way trip.

There are a few articles in the Arts & Letters Daily web site that may relate to some of this, they are :http://www.prospect-magazine.co.uk/ArticleView.asp?Accessible=yes&P_Article=7269 and : http://www.nybooks.com/articles/14796