The Fermi Paradox - Are We Alone in the Universe

[Conservomax]

Fermi's Paradox

Fermi's Paradox (i.e. Where are They?):

The story goes that, one day back on the 1940's, a group of atomic scientists, including the famous Enrico Fermi, were sitting around talking, when the subject turned to extraterrestrial life. Fermi is supposed to have then asked, "So? Where is everybody?" What he meant was: If there are all these billions of planets in the universe that are capable of supporting life, and millions of intelligent species out there, then how come none has visited earth? This has come to be known as The Fermi Paradox.

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 a few million years, every star system could be brought under the wing of empire. A few 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?"

Also, if one considers the amount of time the Galaxy has been around (over 10 billion years) and the speed of technological advancement in our own culture, then a more relevant point is where are all the super-advanced alien civilizations. Russian astrophysicist Nikolai Kardashev proposed a useful scheme to classify advanced civilizations, he argues that ET would posses one of three levels of technology. A Type I civilization is similar to our own, one that uses the energy resources of a planet. A Type II civilization would use the energy resources of a star, such as a Dyson sphere. A Type III civilization would employ the energy resources of an entire galaxy. A Type III civilization would be easy to detect, even at vast distances.

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 extraterrestrial 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.

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Bracewell-Von Neumann Probes:

While interstellar distances are vast, perhaps to vast to be conquered by living creatures with finite lifetimes, it should be possible for an advanced civilization to construct self-reproducing, autonomous robots to colonize the Galaxy. The idea of self-reproducing automaton was proposed by mathematician John von Neumann in the 1950's. The idea is that a device could 1) perform tasks in the real world and 2) make copies of itself (like bacteria). The fastest, and cheapest, way to explore and learn about the Galaxy is to construct Bracewell-von Neumann probes. A Bracewell-von Neumann probe is simply a payload that is a self-reproducing automaton with an intelligent program (AI) and plans to build more of itself.

Attached to a basic propulsion system, such as a Bussard RamJet (shown above), such a probe could travel between the stars at a very slow pace. When it reaches a target system, it finds suitable material (like asteroids) and makes copies of itself. Growth of the number of probes would occur exponentially and the Galaxy could be explored in 4 million years. While this time span seems long compared to the age of human civilization, remember the Galaxy is over 10 billion years old and any past extraterrestrial civilization could have explored the Galaxy 250 times over.

Thus, the question arises, if it so easy to build Bracewell-Von Neumann probes, and they has been so much time in the past, where are the aliens or at least evidence of their past explorations (old probes). So Fermi Paradox becomes not only where are They, but why can we not hear Them and where are their Bracewell-von Neumann probes?

Possible solutions to Fermi's Paradox fall in the following categories:

• They Are Here
  • They Were Here and They Left Evidence
    • UFO's, Ancient Astronauts, Alien Artifacts: all fall under the heading of proposals that aliens are here now (and they call themselves Republicans) or have been here in the recent past. Problem: evidence for aliens is non-existent.
  • They Are Us
    • Humans are the descendents of ancient alien civilizations. Problem: where are the original aliens? Where are all the other alien civilizations
  • Zoo/Interdict Scenario
    • The aliens are here, and they are keeping us in a well designed zoo (cut off from all contact) or there is an interdiction treaty to prevent contact with young races (us). Problem: scenario lacks the ability to be tested. Takes only one ET to break embargo.

• They Exist But Have Not Yet Communicated
  • They Have Not Had Time To Reach Us
    • Speed of light slows communication levels, relativity makes space travel long. ET's message may not have reached us yet. Problem: Galaxy has been around for billions of years, even if one ET civilization formed a few million years before us, the Galaxy would be filled with Bracewell-von Neumann probes.
  • They Are Signaling, But We Do Not Know How To Listen
    • EM radiation, gravity waves, exotic particles are all examples of methods to signal. Problem: they may use methods we have not learned yet, but if there are many civilizations someone would use EM methods.
  • Berserkers
    • The Galaxy is filled with killer robots looking for signals. ET is keeping low. Problem: where are the berserkers coming after us?
  • They Have No Desire To Communicate
    • ET has no interest in conversing with lesser beings. Problem: with millions of possible civilizations, someone would have some curiosity.
  • They Develop Different Mathematics
    • Mathematics is the universal language. But humankind may have a unique system of mathematics that ET cannot understand. Problem: then where are their incomprehensible signals?
  • Catastrophes
    • Civilizations only have a limited lifetime, They are all dead.
      • Overpopulation
      • Nanobots -> Gray Goo Problem
      • Dangerous Particle Physics

• They Do Not Exist
  • We are the First, Life is New to the Galaxy
    • Life is new to the Galaxy, evolution takes time, we are the first civilization. Problem: Sun is average star, if other stars formed a million years ahead of us, then They would be a million years ahead of us in technology.
    

  • Planets With the Right Conditions are Rare
    • Planetary systems are rare
    • Habitable zones, proper distance from star for liquid water, are narrow
    • Galaxy is a dangerous place (gamma-ray bursters, asteroid impacts, etc)
    • Earth/Moon system is unique (large tides needed for molecular evolution)
  • Life Is Rare
    • Life's Genesis is rare
    • Intelligence/Tool-Making is rare
    • Language is unique to humans
    • Technology/Science is not inevitable

In general, solutions to Fermi's paradox come down to either 1) life is difficult to start and evolve (either hard for the process or hard to find the right conditions) or 2) advanced civilizations destroy themselves on short timescales. In other words, this is an important problem to solve in the hope that it is 1 and not 2.

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[Joe Hadenuf]

If conditions are ideal on earth for the development of one intelligent species, why haven't two species developed? A strong conclusion would be that we are unique.

Make that,

There can only be one human species, and there are plenty of other types of species on this planet, literally thousands, some that do have a limited degree of intelligence.

[ThirdMate]

Such as the Neanderthals? But they were something of a subspecies.

Besides, there was plenty of opportunity for a completely different intelligent species to develop in the Americas before contact with Homo-Sapiens.

[ThirdMate]

Let me clarify what I mean by an intelligent species. By intelligent species I mean one which is capable of making and using tools and communicating abstract thought.

That I believe is the condition of intelligence posited in the article.

rgds,
3/M

[roadcat]

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

But they are. There's a possible political explanation for the Fermi Paradox. Every intelligent civilization has their bad eggs, who go on to push an inhibiting culture on the masses and cause extinction before a viable space traveling civilization can take root. On Earth, that inhibiting culture is Islam. They ain't just on Earth, folks, resistance is futile...

[Joe Hadenuf]

Let me clarify what I mean by an intelligent species. By intelligent species I mean one which is capable of making and using tools and communicating abstract thought.

Actually there have been some instances where species on this planet have used tools, chimps and crows, however primitive.

As a matter of fact, we just saw on the discovery channel a week or so ago this crow literally bent a wire to use to stick down inside of bottle to hook food inside of the bottle. We watched in total shock. Again, very primitive, however the bird did make the tool and used it to successfully obtain the food to our total surprise. I understood crows were very intelligent, but this was a real eye opener to say the least.

[Graymatter]

Wow, Fermi asked a good question. I have trouble answering my kid's questions. Example: if a lot of water is aqua-blue colored, and snow is water, why is snow white and not blue?

[ZULU]

Thanks.

Are you really a radioastronomer?

[ThirdMate]

Okay, but do you expect the crow to colonize the universe?

[Joe Hadenuf]

Okay, but do you expect the crow to colonize the universe?

LOL, maybe in several millions years, who knows. The point is there are other intelligent species on this planet besides humans, however very primitive. I for one, put my bet on life outside of earth, both intelligent and non intelligent, and I feel the universe is far to vast for anyone on this planet to say the chances of intelligent life out there are small, if at all. Just because we have no proof at this point, means little, IMO.

[edwin hubble]

"Planets With the Right Conditions are Rare
Planetary systems are rare
Habitable zones, proper distance from star for liquid water, are narrow
Galaxy is a dangerous place (gamma-ray bursters, asteroid impacts, etc)
Earth/Moon system is unique (large tides needed for molecular evolution)
Life Is Rare
Life's Genesis is rare
Intelligence/Tool-Making is rare
Language is unique to humans
Technology/Science is not inevitable "


Here are two more:

1. Early microbial plant life gave off oxygen as a product of photosynthesis.
This eventually formed ozone in the upper atmosphere.
This, over a billion years or so, prevented the otherwise certain disassociation of water in the vapor phase in the upper atmosphere.
Without this ozone (from early life) all water would now be gone from the Earth's system.

2. Tectonic plate motion on the Earth
Among terrestrial planets only Earth has the constant slow motion of the mantle. (although Venus has volcanoes and activity we don't fully understand).
Theories hold that tectonic plate motions give us recirculation of metal elements - necessary for a technology-using civilization.

[Conservomax]

Are you arguing with the article's worth or that of the paradox which many of the world's top physicists have wrestled with for over 50 years?

[AndrewC]

Because of the distances and energies involved. The Fermi Paradox is pure codswallop IMHO.

I take it then that you don't believe humankind can ever explore another solar system. (because if we can then it is a process of time and reproduction etc....)

[Joe Hadenuf]

Because of the distances and energies involved. The Fermi Paradox is pure codswallop IMHO.

I concur.

[Dimensio]

What about Al Gore?

Terrestrial robot.

What about Kerry?

Terrestrial zombie.

[RadioAstronomer]

technological stagnation

Indeed. This is just one more reason that the Fermi Paradox is flawed.

[RadioAstronomer]

I'll throw out another theory, FWIW. What if it's exceedingly difficult for societies to organize on a large scale over an extended period of time? For a galaxy-spanning civilization, this would be a requirement for large-scale interstellar colonization.

Agreed. However, IMHO the distances alone will prevent an interstellar civilization.

Consider our own planet, we create extra-national organizations such as the UN and it becomes corrupted and ineffective. We've even tried international efforts on space projects and we have a clunky sinkhole of money in LEO that will never be completed as it was originally intended.

Agree also. Big sigh here. (And I even worked on the Space Station)

I haven't seen evidence that we're capable of mounting an expedition much past Mars. To think that we could not only colonize our own star system and then reach out on a large and continuous scale to propagate throughout the galaxy using a supranational organization (UN on steroids) is laughable.

I don't even seeing us going back to the moon any time soon, much less Mars or beyond. :-(

Maybe the best that could be attempted would be sporadic probes of a few nearby star systems, probably robotic, that would do a quick flyby or a temporary orbital surveillance of other star systems. It would be small scale, extremely rare, and very unlikely we would ever notice such a probe, even if it passed by during an age of technical sophistication of the target star system.

Would take lifetimes. Can a probe last this long? We have quite a time getting our probes just to the edge of our own solar system.

[RadioAstronomer]

Besides, those who wonder should check out the theory of Directed Panspermia - a realistic solution, but it begs the question of the initial source for galactic life.

I just don't see that either. Evolution and Biogenesis are the best theories we have to date for life arising and diversifying on our planet.

[RadioAstronomer]

I'm a bit perplexed why the writer would have included Drake in the article. Sort of made me think...wtf??

The only thing I can think of is that the Drake Equation has a correlation to the Fermi Paradox by estimating the number of tool building species out there. However, the reciprocal does not exist IMHO. No matter what the Drake Equation estimates, it will not bolster the Fermi Paradox.

I am doing well, but extremely busy. Sigh! (eats into my freeping! LOL)

[RadioAstronomer]

Observation contradicts that conclusion. So ... where are they?

Separated by time and distance if they exist.

[RadioAstronomer]

Are you really a radioastronomer?

I have worked in that field, however, what I do for a living now is spacecraft/satellite engineering, design, control, and operations.