Enrico Fermi and extraterrestrial intelligence

Enrico Fermi and extraterrestrial intelligence
Nuclear physicist Enrico Fermi won the 1938 Nobel Prize for a technique he developed to probe the atomic nucleus. He led the team that developed the world’s first nuclear reactor, and played a central role in the Manhattan Project that developed the atomic bomb during World War II. In the debate over extraterrestrial intelligence, he is best known for posing the question ‘Where is everybody?’ during a lunchtime discussion at Los Alamos National Laboratory. His question was seen as the basis for the “Fermi Paradox”. Credit: Smithsonian Institution Archives

It's become a kind of legend, like Newton and the apple or George Washington and the cherry tree. One day in 1950, the great physicist Enrico Fermi sat down to lunch with colleagues at the Fuller Lodge at Los Alamos National Laboratory in New Mexico and came up with a powerful argument about the existence of extraterrestrial intelligence, the so-called "Fermi paradox". But like many legends, it's only partly true. Robert Gray explained the real history in a recent paper in the journal Astrobiology.

Enrico Fermi was the winner of the 1938 Nobel Prize for physics, led the team that developed the world's first nuclear reactor at the University of Chicago, and was a key contributor to the Manhattan Project that developed the atomic bomb during World War II. The Los Alamos Lab where he worked was founded as the headquarters of that project.

The line of reasoning often attributed to Fermi, in his lunchtime , runs like this: There may be many habitable Earth-like planets in our Milky Way galaxy. If intelligent life and technological civilization arise on any one of them, that civilization will eventually invent a means of interstellar travel. It will colonize nearby stellar systems. These colonies will send out their own colonizing expeditions, and the process will continue inevitably until every habitable planet in the galaxy has been reached.

The fact that there aren't already aliens here on Earth was therefore supposed to be strong evidence that they don't exist anywhere in the galaxy. This argument actually isn't Fermi's and was published more than 25 years later by astronomer Michael Hart. It was elaborated in a paper published by the cosmologist Frank Tipler in 1980.

Fermi's lunch conversation really did happen. Although he died just four years later of cancer, physicist Eric Jones published the recollections of the physicist's luncheon companions more than thirty five years later. Among these companions were Edward Teller, Emil Konopinski, and Herbert York, all eminent physicists and veterans of the Manhattan Project. Teller played a central role in the development of the hydrogen bomb. Konopinski studied the structure of the atomic nucleus, and York became director of Lawrence Livermore National Laboratory.

During the walk to the Fuller Lodge, the physicists discussed a recent spate of UFO sightings, and a cartoon in the New Yorker Magazine depicting aliens and a flying saucer. Although the topic of conversation moved on as the group sat down for lunch, Edward Teller recalls "in the middle of the conversation, Fermi came out with the quite unexpected question 'Where is everybody?'…The result of his question was general laughter because of the strange fact that in spite of Fermi's question coming out of the clear blue, everybody around the table seemed to understand at once that he was talking about extraterrestrial life".

In his account of the famed luncheon, Teller wrote "I do not believe much came from this conversation, except perhaps a statement that the distances to the next location of living beings may be very great and that, indeed, as far as our galaxy is concerned, we are living somewhere in the sticks, far removed from the metropolitan area of the galactic center".

York recalled a somewhat more expansive discussion in which Fermi "followed up with a series of calculations on the probability of earthlike planets, the probability of life given an earth, the probability of humans given life, the likely rise and duration of high technology, and so on. He concluded on the basis of these calculations that we ought to have been visited long ago and many times over".

According to York, Fermi supposed the reason we hadn't been visited "might be the interstellar flight is impossible, or if it is possible, always judged not worth the effort, or technological civilization doesn't last long enough for it to happen".

So Fermi, unlike Hart, wasn't skeptical about the existence of extraterrestrials, and didn't view their absence from Earth as paradoxical. There is no Fermi paradox, there is simply Fermi's question "Where is everybody?", to which there are many possible answers. The answer that Fermi preferred seems to be that, either interstellar travel isn't feasible because of the enormous distances involved, or Earth simply had never been reached by alien travelers.

Interstellar distances are truly vast. If the entire solar system out to the orbit of Neptune were reduced to the size of an American quarter, the nearest star, Proxima Centauri, would still be about the length of a football field away. A practical starship would either need to travel very fast, at an appreciable fraction of the speed of light, or be capable of supporting its crew for a very long time. While either is theoretically possible, seems to present day humanity to be such a grandiose undertaking that it's not clear whether any civilization would be able or willing to muster the enormous resources needed.

Where did the confusing of Fermi's question with Hart's argument come from? Carl Sagan mentioned Fermi's question in a footnote to a 1963 paper. After the publication of Hart's paper in 1975, Fermi's question and Hart's speculative answer became associated in many writer's minds. Fermi's question seemed to beg Hart's answer, and "Fermi's paradox" was born. According to Robert Gray, the term was coined by D. G. Stephenson, in a paper published two years after Hart's.


Explore further

Self-replicating alien probes could already be here

More information: "The Fermi Paradox Is Neither Fermi's Nor a Paradox" Astrobiology. March 2015, 15(3): 195-199. DOI: 10.1089/ast.2014.1247
Journal information: Astrobiology

Source: Universe Today
Citation: Enrico Fermi and extraterrestrial intelligence (2015, April 8) retrieved 19 July 2019 from https://phys.org/news/2015-04-enrico-fermi-extraterrestrial-intelligence.html
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Apr 08, 2015
If intelligent life and technological civilization arise on any one of them, that civilization will eventually invent a means of interstellar travel. It will colonize nearby stellar systems.

And therein lies the error. If you can survive the lengthy trip from star A to star B then

a) you are either in a bodily form (e.g. a machine form) that can survive space or
b) you can create space habitats/ships that can support biological life indefinitely

Either way you can just stay in space forever and not fight with an (assuredly) hostile planetary environment that would require full enclosure and full biosphere control at all times in any case.

There's no point in colonizing another solar system's planets whatsoever.

Apr 08, 2015
Well, another reason why we may ask the question, "where is everybody" is that when intelligent species reach the level of technological expertise that would enable them "to seek out new life and new civilizations", they have also developed a strict set of guidelines preventing them from just showing up on a planet like ours (i.e. having a species with technology so primitive as to preclude practical interstellar travel). We may be watched from afar with great interest, or merely curiosity, or we may be visited by hologramic probes or robotic drones to collect historical data on us. Perhaps only scofflaw aliens that don't follow galactic protocol, or outcasts, would dare to land here and show themselves. Such aliens might just present themselves as "gods" - what a concept!

Apr 08, 2015
Current efforts to create "Warp" drive by NASA are theoretical and preliminary so far, but appear to be possible within the relativistic universe we live in. I think @LariAnn has the right of it, and there is a strict "Prime Directive" in effect. (I sometimes wonder if we are not really in a "Truman Show" world.) However that does not preclude robot civilizations that are content to exist in a local area such as @antialias_physorg suggests. One wonders if (postulated) robot civilizations would follow humanities path of empire building or not. Perhaps the onlookers are robots looking for new biological intelligences to improve their own evolution by including the nuanced diversity caused by evolutionary forces as new data. (BTW: @standfast18 may also be right.)

Apr 08, 2015
interstellar travel is a stupid idea. No one in their right mind would undertake it for any purpose. There is no purpose or value to sending people or objects to another star system and it will take thousands of years to get there physically.

The only thing that makes any sense is to transmit information and communicate back and forth even though it will take hundreds of years to say hello and hear a reply.

Everyone will always stay in their own star system no mater how advanced they get.

There is most likely an existing intergalactic internet that we will connect to someday, however communication will be no faster than at the speed of light unless there are ways to communicate through wormholes.

Apr 09, 2015
interstellar travel is a stupid idea. No one in their right mind would undertake it for any purpose.

The 'travel' part I can understand. Think about either a fully artificial AI or a human intelligence transferred to a machine. something like that could well travel the distance and just switch off (or go into extreme slow motion) during the journey.

For communication purposes an intelligent probe would certainly beat sending photons back and forth between solar systems. For one there's no chance of transmission error (with the exception of total destruction)...and the probe could arguably negotiate/communicate/collect information a whole lot faster than repeated signal exchanges - even given a decade or century long flight time there and back. The ability to take measurements in situ is certainly far greater than doing so at light years remote, too. And being intelligebt it could adapt to unforeseen situations better than an automatic probe.

Apr 09, 2015
Lets say for argument that a civilization similar to ours exists 25 light years away.

Lets say they received our radio or TV transmissions (from 50 years ago in 1965) and replied immediately to let us know. We receive the reply today and reply to them. They will get it 25 years from now. 50 years from now we will get the first useful bit of information from them. If you have a question for them then you will wait another 50 years to ask and answer it. That's about as fast as anything can ever happen. One generation can ask a question and the next generation gets the reply. All assuming they are only 25 light years away which is not very likely. At 100 to 1000 light years away which is more likely and you see the Romans asking the question and the Americans getting the answer.

Anything else like sending an object will take 10,000 years to get there and another 10,000 years to get back ... a totally ridiculous undertaking of no value to us or anyone else.

Apr 09, 2015
interstellar travel is a stupid idea. No one in their right mind would undertake it for any purpose. There is no purpose or value to sending people or objects to another star system and it will take thousands of years to get there physically.

The only thing that makes any sense is to transmit information and communicate back and forth even though it will take hundreds of years to say hello and hear a reply.

Everyone will always stay in their own star system no mater how advanced they get.

There is most likely an existing intergalactic internet that we will connect to someday, however communication will be no faster than at the speed of light unless there are ways to communicate through wormholes.


Perhaps a civilization a million, perhaps a billion years older than ours could have something to teach us? Sometimes the lack of imagination people display is the thing most boggling to my mind!

Apr 09, 2015
Yes I agree that humanity is boggled down because of peoples lack of imagination. Even with a limited amount of imagination one can imagine that sending objects or life forms to another star system is a stupid idea.

There is not one iota of known scientific possibility that would make this something imaginable.

Humanity should not confuse using our imagination to pursue knowledge with whimsically dreaming about impossible things to waste time and resources chasing boondoggles.

Lets say their is some civilization out there a billion years ahead of us that has found ways to travel through time so that distances are no longer meaningful ... then the question can be "where is everyone ... from all eternity pass and future"? That type of civilization can already be taken as proven to not exist, because they would of been here by now.

Use your imagination to contemplate real science possibilities rather than magical whimsical thinking of impossible nonsensical things.

Apr 09, 2015
Use your imagination to contemplate real science possibilities rather than magical whimsical thinking of impossible nonsensical things.


Stick to the lab. That's where you belong; banging your head against the wall because things seem so impossible to you.

Apr 10, 2015
we are discussing the Fermi Paradox. I am not against exploration. But exploration needs to make sense. The most we can expect to do in the next 100 million years is colonize a few of the nearby star systems. At best say 5 light years distant since it will take 10,000 years to reach any of them. A city size population will need to be sent on a moon sized ship so that 10,000 years later some generation of people will have a very small chance of being alive when they get there.

As far as our star system is concerned ... we should have colony bases on Titan twenty years ago if not for the idiots running things. As for Mars ... it is a useless hunk of rock ... nothing worth while going there for anymore. Moons of Jupiter and Saturn are much more important and suitable for colonization ... and we should have gone there long ago.

Apr 10, 2015
As far as our star system is concerned ... we should have colony bases on Titan twenty years ago if not for the idiots running things. As for Mars ... it is a useless hunk of rock ... nothing worth while going there for anymore. Moons of Jupiter and Saturn are much more important and suitable for colonization ... and we should have gone there long ago.


We can agree on that. Have a great weekend.

Apr 12, 2015
You use a world ship. De-orbit a comet or something like that with a base and living quarters build on it. This provides gravity and water for generations.

Then you fly to the other star and discover that habitable-looking planet isn't actually habitable after all. Now you're screwed. Should have sent a small probe first (sarcasm).

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