We’ve talked often enough about the so-called ‘Fermi paradox’ in these pages, but Gregory Benford recently passed along a new paper from Robert H. Gray making the case that there is in fact no paradox, and that Fermi’s intentions have been misunderstood. It’s an interesting point, because as it turns out, Fermi himself never published anything on the subject of interstellar travel or the consequences if it proved possible. The famous lunch conversation at Los Alamos in 1950 when he asked ‘Where is everybody’ (or perhaps ‘Where are they’) has often been seen as a venue for Fermi to express his doubts about the existence of any extraterrestrial civilization, and the ‘Fermi Paradox’ has become a common trope of interstellar studies.
Robert Gray (Gray Consulting, Chicago) believes this is a misunderstanding, and sorts through the aftermath of that particular event. It would be another 27 years before the term ‘Fermi paradox’ even appeared in print, inserted into a JBIS paper by D. G. Stephenson. This followed upon Michael Hart’s 1975 discussion, which Gray sums up as ‘they are not here; therefore they do not exist,’ an argument Hart used to question the wisdom of pursuing SETI. Frank Tipler’s subsequent paper (1980) took us into the realm of artificial intelligence, claiming that self-replicating probes could use even current spacecraft speeds to colonize the galaxy in less than 300 million years. Tipler concluded that we were probably the only intelligent species in the universe since we had not encountered evidence for the existence of such probes.
Maybe we should leave Fermi’s name out of this, writes Gray:
Using Fermi’s name for the so-called Fermi paradox is clearly mistaken because (1) it misrepresents Fermi’s views, which were skeptical about interstellar travel but not about the possible existence of extraterrestrials, and (2) its central idea ”they are not here; therefore they do not exist” was first published by Hart. Priority of publication and accuracy suggests using a name like Hart-Tipler argument instead of ‘Fermi paradox.’
Image: Enrico Fermi (1901-1954), whose famous question may have been misunderstood by subsequent writers.
I notice that as it currently stands, the Wikipedia entry for Fermi Paradox describes it as “…sometimes referred to as the Fermi-Hart paradox,” but Gray can turn to no less an eminence than Iosif Shklovsky, Russian astronomer and co-author, with Carl Sagan, of Intelligent Life in the Universe (Holden Day, 1966), who preferred the term ‘Hart Paradox,’ while Stephen Webb opined we might try ”Tsiolkovsky-Fermi-
Viewing-Hart paradox” in his book Where Is Everybody (Copernicus, 2002). David Viewing had argued in 1975 that extraterrestrial civilizations might well exist despite the factors that Hart noted, meaning we should actively search for evidence of them.
Gray even falls back on Konstantin Tsiolkovsky, who wondered about questions like these in the 1930s. But is there any paradox here? Gray thinks not, for a paradox implies a statement that is self-contradictory, the nature of the contradiction suggesting that something is wrong:
The Hart-Tipler argument takes the seemingly obvious fact they are not here as evidence that a premise ”technological extraterrestrials exist” must be false, because if they did exist, the colonization argument leads to the conclusion they are here, which seems absurd. This is a reductio ad absurdum argument, not a paradox, although like a paradox it depends on every statement being true—yet the argument consists of many speculations which are not known to be true.
Good point. Consider which statements we cannot know, starting with the assumption that interstellar flight is feasible, although most of us here believe that if we can envision it with our current level of technology, then it is at least a rational assumption. In fact, the original Project Daedalus was conceived in part as a way of showing that if we could, at levels of scientific development not far ahead of our own, design a starship, then surely other civilizations of much longer duration than ours would have found better ways to make these things happen.
As for the other implicit assumptions, the unknown nature seems clear enough. Would the galaxy indeed fill, as per Tipler, with self-reproducing probes in the kind of timeframes he imagined? Would this ‘colonization’ take a form we could understand or detect (Gray doesn’t get into this question, though it seems pertinent). Would any presence from another star system be likely to persist over millions or even billions of years? Clearly we have no answers here, and have no way of knowing whether we ever will. Assuming that each of these positions is therefore true and that Earth would be a visited world is thus a questionable stance.
According to three of those who were there (Emil Konopinski, Edward Teller, and Herbert York, all quoted in the Gray paper), Fermi’s point was not that extraterrestrial civilizations did not exist, but that interstellar travel that might bring them here was infeasible. As Gray sees it, the true ‘they are not here; therefore they do not exist’ argument should be credited to Michael Hart and Frank Tipler. The question may not be purely theoretical, for it turns out that this Hart-Tipler argument became one of the reasons given for canceling NASA’s SETI program in 1981, being cited by William Proxmire, who referenced Tipler’s work. Gray asks whether continued use of it in this way may perpetuate low funding levels in SETI. And this is worth quoting:
The literature on searches (Tarter, 1995) indicates that only a small fraction of the radio spectrum has been searched—0.3 GHz in surveys covering much of the sky (Leigh and Horowitz, 2000) using transit observations, and 2 GHz in targeted searches of 800 stars (Backus et al., 2004)—out of a terrestrial microwave window from 1 to 10 GHz, a free-space window up to 60 GHz (Oliver and Billingham, 1971), and much more electromagnetic spectrum beyond, including optical. Few searches would have detected low-duty-cycle signals anticipated by some (Benford et al., 2010; Gray, 2011), because both radio and optical surveys typically observe positions for only minutes. An incomplete search for signals cannot be used as evidence of complete absence of technological extraterrestrials.
The paper is Gray, “The Fermi Paradox Is Neither Fermi’s Nor a Paradox,” Astrobiology Volume 15, Number 3 (2015). Abstract available.
ljk & Al Jackson re: Fermi Paradox’s contribution to SETI’s funding and public perception issues:
In the USA, the issue is also rooted in a need for acceptance and validation via values and beliefs fostered by the powers-that-be and spread via the mass media. This is pervasive throughout American society.
Once SETI was publicly and thoroughly ridiculed by powers-that-be, people didn’t want to be seen as supporters of SETI anymore. So regarding the subject of ET intelligence, most Americans go along with the ridicule or remain silent, to protect their societal acceptance and validation. Few vocally support it.
This is seen in global warming as well in the USA. Once enough politicians and radio talk shows and television hosts thoroughly and consistently ridiculed it, most of American society went silent on the issue. The vast majority of people understand the huge threat of global warming, but they speak in hushed tones among friends, or stay silent. They want to avoid any ridicule, to avoid bringing attention to themselves on a possibly “controversial” issue, following their instinctive drive to ensure that they “fit in” with society as a whole.
The “War on Terrorism” in the USA is one more example. The vast majority of powers-that-be proclaimed over and over again, with the compliance of the mass media, that if one does not support this so-called War then one is foolish, naive and unpatriotic. Vocal opposition to the War on Terrorism dried up by 2004 to the point where most of society either vocally supported it or kept silent.
There are many vocal proponents and opponents of the above issues, but they’re dwarfed by the silent millions. The need to be accepted and validated by society, via values and beliefs spawned by the powers-that-be and fostered by the media, is an incredibly strong driver in the USA.
I find the Zoo Hypothesis to be very improbable to put it mildly. I do think that there may be another answer to the Fermi- Hart- Tipler Paradox ; traveling across the Milky Way Galaxy may just be too “hard”. The great distances involved, the Light Speed limit, lack of a reliable propulsion/power source (?),
too costly economically/socially, short “lifespan ” of advanced civilizations, no economic , societal , or other incentives, etc.
While I believe that none of the above precludes the expansion of a civilization into the Cosmos, I see these to be reasonable answers to the question”Where are they ?”. Since I do believe that “warp drives, worm holes, and FTL propulsion are most likely fanciful constructs , the nearest ET’s may be too far to reach us or for us to reach them.
@Erik Landahl
You also miss an extremely important point when you bring up the fact that there is a ‘silent majority’. We are entering into a time in which Edwards Snowden clearly has shown that the government now is interested in what the populace is doing.
As in Nazi Germany whenever there was coworkers or so-called friends or strangers one bit one’s tongue on what was said. The Gestapo was always interested in gathering information and trying to find out who was of member or not. Are you aware that the Gestapo even had a branch in its organizational chart in which it looked at people who were loners ? Today, it’s becoming very unwise to say too much, and with the Internet, it becomes even more unwise. The powers that be that you mentioned, now really have become the powers that be, and they decide the course of what is going to happen or not happen. So I do think that there’s a lot more than just a question of looking for extraterrestrials: there is money, power and other issues in the mix. You have to look at the entire picture.
@william
So true. I agree.
Sagan never quite said as much, but Pale Blue Dot certainly seemed to be hinting at the possibility that funding for META was cut off in reaction to the observation of anomalous narrow-band radio emissions in the galactic plane. Though apparently there is now thought to be an astrophysical explanation for at least some of these, that could not have been known at at time.
Such hostility seems at least consistent with how powerful factions have behaved in the past, in that a rapid imperial expansion and consolidation is generally accompanied by isolationism, as happened in Japan at the conclusion of its Warring States era. Securing one’s hold on one’s domain and assimilating conquered cultures is a lot easier if one can create at least a semblance of a case for the universality of one’s own culture, which obviously would be badly undercut by exposure to one or more radically different outside perspectives.
Who speaks for Earth, and does it really matter?
Last month, a scientific conference featured a session debating the merits of actively transmitting messages in the hopes that other civilizations might one day detect them. Jeff Foust examines the arguments and whether the debate really has merit.
Monday, March 9, 2015
http://www.thespacereview.com/article/2708/1
To quote:
Current SETI searches assume that other civilizations are actively transmitting, said the SETI Institute’s Douglas Vakoch at the press conference, but that need not always be the case as our own technologies improve.
“At this point, in our passive SETI searches, we require the other civilization to be sending an intentional signal more powerful than our leakage radiation,” he said. “But that would change in about two or three centuries.”
There’s also the issue of how to conduct any sort of international consultation, including the requirement in the declaration for a “worldwide consensus” before sending any signals. Society is not very good at developing a worldwide consensus on any issue, and if we were able to develop one regarding SETI, would that really be representative of the fractious nature of our civilization?
Brin’s hope that such a consultation might attract half a billion people—an audience usually reserved for a few major global sporting or entertainment events—seems difficult to justify.
And, for all the discussion about Active SETI, there is very little activity. “There have been all sorts of stunts in the last 20 years,” Brin said, but few that have used “really substantial instruments” that produce signals that could be detected at great distances.
Those small-scale efforts, Vakoch said, may be analogous to the origins of SETI in the 1960s. He suggested a more focused effort might use the Arecibo radio telescope to broadcast messages to a targeted group of relatively nearby (within about 25 parsecs) stars, perhaps tacked on to ongoing use of Arecibo for planetary radar studies.
And why do it? “If you’re going to conduct SETI experiments where you’re trying to look for putative alien broadcasts, it may be very instructive to have to construct a transmitting project,” Shostak suggested. “You walk a mile in the Klingon’s shoes, assuming they have them.”
Brin said he has no problem with developing messages, not for transmission but to better understand how to interpret them. That includes a project to construct a message to be transmitted not to another star system, but to NASA’s New Horizons spacecraft, which will store the message in its onboard flash memory after its completed its science mission in the Kuiper Belt and its heading beyond the solar system. Hypothetically, that message could be found by aliens—much like those on the Pioneer and Voyager spacecraft—but it’s really more about us, and figuring out what we want to say about our civilization.
“We are learning so much so fast,” Brin said, citing the explosion of exoplanet discoveries over the last two decades. He wonders why, for example, there’s no evidence of extraterrestrial life on the Earth even though it was “prime real estate” for supporting life for two billion years. “There is a mystery. Let’s embrace it. Let’s discuss it. It’s fascinating.”
“This is an incredible time for the adventure,” Brin said. Of that, at least, there is little debate.
If ever a species develops to the point where they can and do colonize neighboring star systems, it is obvious to me that their descendents will likely, eventually, do so again, and in time there will be so many colonies that are ready and willing to continue the process that it becomes unstoppable. Just as every corner of the Earth is now suffused with life to the greatest extent possible, the galaxy will be suffused with colonies of colonies of …. Earth.
The term “civilization” is a red herring in this whole argument. The Roman empire fell, as did hundreds of others. Humanity, on the other hand, persists. Life, persists. Life has persisted for billions of years and it is nearly inconceivable that it will ever end. The vastness of time combined with the ability to traverse interstellar distances will swiftly and easily overcome the vastness of space. The galaxy will be filled with advanced technological life (Not one “civilization”, but billions), and the only way you can still hope for ETI in the present is by making the contrived argument that somehow, this advanced form of life naturally and necessarily takes a form in which it would be completely undetectable by us.
Or, as some have said, we are simply the first. This, however, is the same as being alone, is it not?
The zoo hypothesis, once you realize there will be millions of independent and diverse civilizations, instead of a single “wise” one, is plain ridiculous. That does not even take into account that Earth would have to have been already under protection before there was complex life on it.
It does not matter whether these colonizing descendents of ours (or of the conjectured other ETI) are biological, mechanical or whatever else. They do not even need to be intelligent, really. All that matters is that there are some amongst them that are capable and motivated to seek out new star systems for colonization. Chain reaction and the stirring effect of galactic motion will do the rest. Within just a few galactic revolutions, their descendants will be everywhere.
Maybe the Fermi question can be put a little differently this way: Either they (meaning a self-replicating, star-colonizing lineage) are here (meaning right here, in the solar system, right now), or they do not exist. If you prefer the former, the burden is on you to explain how it might be that we do not see them.
The notion that our solar system is not interesting enough is almost as ridiculous as the zoo hypothesis. The vastness of time works against it. We have perfectly fine resources (starlight, asteroids, planets). After sufficient time, when most other systems are occupied, perhaps even used up, our solar system, no matter how ordinary, will be valued simply for still being available.
Have you ever wondered why there are people living in Pahrump, Nevada? Not a particularly interesting place, and yet, it has been parceled out and is being lived in, just a few hundred years after colonists first set foot on the continent.
We have sent actual physical members of our own species only to our nearest neighbour world, and that only very briefly. Isn’t it a bit soon in the game (by many centuries) to be deciding if interstellar colonisation is viable? The simplest answer (my opinion only) is that it is not, or it will not be in most cases. The other issue is the ‘willingness’ side of things. What if there is good reason, still for us to discover, why no-one would be willing?
It takes a special mindset to want to leave home, especially if leaving home means going into space and even moreso if one wants to go to another star.
As we have seen, for most of human history the idea of space exploration was not even conceivable and when it was, the vast majority of people considered it to be an absurd fantasy at best. Even when the Space Age finally began, it was due to a combination of political and military reasons why it even happened at all: Science was a backseat rider but it was used as the civilizing face of why we were going to the stars.
Most people still have no real interest in space. They cannot relate to it for cultural and evolutionary reasons. Our current space programs are riding on the dying waves of the reasons we went into the final frontier in the first place. If there was real enthusiasm for a Mars colony or a robot probe to Alpha Centauri, you know the money and resources would have poured in for those ventures a long time ago, recessions and other social issues be damned.
So here is my idea why we haven’t met ETI yet, take as you will: Evolving to where you can think beyond staying safe from predators and getting your next meal or mate is a long and strenuous journey, one which few make without a lot of underlying support from your society. Thinking outside the box called your planet, especially if your society cannot see the benefits from voyaging to other worlds, is both difficult and roadblocked by societal peer pressure.
I know we have only one example of such behavior so far, but look at the other intelligent beings on Earth: Cetaceans have been around far longer than humans yet they have not developed a space program. Can an aquatic species be able to or care at all about exploring and settling space? What if advanced species decide that it is easier and safer to just stay home? They could observe the galaxy remotely with powerful space telescopes.
We have also seen that fast interstellar is very difficult to do and even slow methods have their issues, especially if it involves keeping a group of people alive for generations. But nothing holds an idea back more than a lack of support from the majority or those key people who could make it happen but do not.
So my theory is: Along with the fact that there are 400 billion star systems in the Milky Way galaxy – and now perhaps even more based on very recent developments – and that most stars are at least several light years apart at best, could it be that space travel is something too difficult not just technically but culturally? I know it only takes one species to break the barriers, but what if no one has and we aren’t far enough along to realize that yet? I think colonizing the galaxy involves a number of factors of which we are only aware of some at this point. And I am not even talking about some hypothetical ETI keeping us “safe”.
ljk, I have stated in earlier posts that I believe that the distances between the stars and the lack of feasible fast propulsion systems may actually explain the lack of evidence for ETI’s . I am not sure that we as a species are actually universally “hot-wired” for space exploration in our genes. Our various collective entities – nations, corporations, etc. – will hopefully decide for economic, political, societal, or other reasons to support the creation of the interplanetary infrastructure that will emerge over future decades/centuries.
Perhaps such a future society would embark on more fruitful interstellar searches for ETI’s. By the way, I do not believe that ETI is likely to arrive here or anywhere else via wormholes , faster-than-light drive, or warp drives.
()Perhaps the key to interstellar travel will be humans with vastly enhanced or extended healthy lifespans/artificial intelligence platforms or some combination of both.
John, you have completely missed what SETI is about. Radio SETI presupposes that their exist within our galaxy at least a hundred current ETI broadcasting to the rest of it with many times more power in their carrier signal than all the electricity our modern world can produce. Think of worlds that much more powerful than ours and that much more interested in messaging the galaxy than we are, yet with no space travel capacity. It doesn’t make sense does it!
I tend to agree that some form of the’cultural’ explanation would fit – the way individuals act whe n grouped into societies can be extremely counter intuitive. Interstellar travel, or even significant off world expansion, would require massive resource commitment. Perhaps there isn’t sufficent gain, or perhaps some general imperative of how culture evolve means that no one really tries for interstellar exploration. As a physicist I’m horrified to say this, but perhaps the answer will one day come from the field of exo-sociology!
It may also be a down to a genral technical argument: by the time a civilisation has the ability they can accomplish all they would want to in terms of expoloration and species preservatgion without the need to boldly go anywhere physically.
Or a combination of many factors – social evolution, technical difficulty, sustainability…. perhaps the tide is genrally against interstellar colonisation and any efforts that do arise grind to a definative halt within a few iterations?
Which is not to say WE shouldn’t try.
Then John, we are beset by another problem. In our subconscious we think that ETIs would not only be very different from us, but very similar to each other, each one of them unchanging in its outlook, and without any factions.
On the other hand we realise that for us, the human world would have been very different than it is now had the Nazis or Communists ever achieved total global domination. Why should we expect ETI to class in such uniform fashion.
Given the immense resources that an interstellar colonisation effort would need I imagine that only a species with very little internal division, focused on the colonisation goal almost uniformly, would stand a chance of success.
Perhaps that is a part of the answer: Such a state of unity and singular focus is what an interstellar colonisation effort requires, and is a vanishingly rare state when a race has sufficient excess resources to to undertake such an effort.
‘It would only take one race that existed in such a state to break the barrier, and quickly colonise the galaxy’ is an argument born of our asumption that ETI’s would be the same across time: Even if the home world attains such a state for long enough to succeed, the colony worlds would also need to reach such a state, and at a point in their history where they had the immense excess of resources to attempt such a colonisation attempt.
If internal diversity and factionisation are the rule amongst civilisations that develop technology then we might have overestimated how likely any given civilsation or colony is to attempt interstellar colonisation and succeed.
….not all ETI’s might eb diverse and factionated in nature. But nature does not drive development unless there is an internal competition, or external need for it, so an homogeneous ETI would perhaps not develop, or do so only very very slowly, once it has mastered its homeworld and natural predators. Again, this would make the chyances of colonising another star system very low.
It is possible to imagine special cases:for example two intelligent technologcial species ahring one world, internally uniform and focused but in competition with each other. but all the exceptions I can think of only apply to a speciic part of that worlds history, or to a single specific world.
I am very likely missing something here, but right now I don’t see the massive effoirt needed being very easy for a civilisation to attain and keep going, especially across the geologic periods of time needed to colonise large sections of the galaxy
So where did that crazy equation we sometimes see come from? The one with all the wild assumptions for premises?
Do you meanthe Drake equation? The history of that is extremely well documented. Jill Tarter recently did an excellent video that explains it more clearly than I can: https://youtu.be/6AnLznzIjSE , although my thoughts are here: http://www.wowsignalpodcast.com/2014/12/burst-2-through-lens-of-drake-equation.html
The factors in the Drake equation are not premises or assumptions. Just factors. When Drake originally wrote it down, we only had a good estimate for one of the factors. Now we have have respectable estimates for the first three. Estimating the fourth will either require much better telescopes or a major discovery at some place like Enceladus.
I think you are missing that the “keep going” and “geologic periods of time” parts are not actually limitations. The only assumptions you have to make is that a civilization can pull it off once, and that both its descendents and those of the daughter colony have a chance of pulling it off again some time in the future. There is no requirement for a sustained effort of any type in between, nor that any aspects of the “civilization” be preserved between attempts, nor that any memory at all remains between successive efforts (although such memory will no doubt exist and be helpful).
The geological time actually helps, too, because the more time is available, the more likely successful colonizations will occur, eventually.
You and William Collins argue that colonization is impossible or extremely unlikely, which, of course, is a valid solution to the problem. I just think it is a bleak one, and closely related to the ‘Future Great Filter’ doomsday solution. It serves to allow the possibility of ETI, but at the same time it ensures we will never meet them. Where is the fun in that? I’d rather have us be alone now, but with a future ahead of us that has our descendents spread across the galaxy in billions of interesting, interacting civilizations.
Let me make an addendum or even a revision of what I wrote earlier: humans will expand across the galaxy in the same way that our ancestors expanded across this planet albeit slowly. I believe the immense distances, the humongous societal costs, and the constraints of the “cosmic speed limit” will impact the extent that our space traveling descendants interact with each other. ( Perhaps advances in biological science/medical care will extend the lifespan and the durability of traveling humans). I truly believe that there are other ETLI’s “out there”. I sure hope that we are able to “talk” to them some day. That would be “fun”
Yes Eniac, it’s not just that we do not need a sustained effort, it is that at each iteration time of this mother daughter colony splitting process, either self-destruction rates or spreading times must go up exponentially, to stop a single start filling the entire galaxy in just a few million years.
What is being cosstituted as intelligence is an assumption.
That civilization would arise from intelligence is an assumption.
That a civilization (culture) would then jump through the very specific hoops to become the kind of resources-based expansionism that brings about an voyager-explorer mindset is an assumption
That the previously mentioned rescources-based expansionist culture would find it worthwhile to gamble the huge amounts of resources needed to send hardware out to…. Where? is a HUGE assumption.
That any civilization or culture would last long enough to do any of this is the biggest assumption of all. We do know one thing about civilizations. They all eventually fall
William Collins: You are correct in noting that interactions amongst our descendant civilizations will be constrained by the cosmic speed limit. This will make interstellar trade nearly impossible: who wants to wait decades for payment? Government, too: who wants to wait decades for instructions from the central authority? And, best of all, war: act on a decades old grievance by sending an expeditionary force that will take decades to arrive? With news of success or failure arriving only decades after that? Who has the patience?
The only sensible form of interstellar interaction I can envision is cultural/historical. It will be fun to hear about other cultures, even if they are so distant that two-way interaction is out of the question. It will be like having a million world histories, rather than just one. The interstellar future belongs to the historian!
Also: A billion TV channels instead of dozens. A multicultural Nirvana, all for consumption, without interaction.
One of the great ironies of this discussion remains the fact that we only have one observed model for a living planet much less a a technologically advanced civilization. After all, there are other “big brained” species on our planet that have existed without any perceivable use of technology over the course of millions of years. Examples that come to mind: dolphins, elephants, octopi, wolves, whales , and chimpanzees. Considering how long it took for an advanced civilizations to rise on our planet, perhaps complex even intelligent life is plentiful in the Galaxy with a fairly infrequent occurrence of technologically advanced (read Type 1) societies . As I said , we have our beloved blue planet as the sole model or example of life’s evolutionary pathways.
Beyond “Fermi’s Paradox” I: A Lunchtime Conversation- Enrico Fermi and Extraterrestrial Intelligence
by PAUL PATTON on APRIL 7, 2015
Part 1
http://www.universetoday.com/119727/beyond-fermis-paradox-i-a-lunchtime-conversation-enrico-fermi-and-extraterrestrial-intelligence/
To quote:
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.
I read the article and an additional conclusion that I picked up on is as follows: alien travelers chose not to invest the tremendous resources that it would take to fly across interstellar space to our solar system which may be located in the Milky Way’s “sticks”.
Beyond “Fermi’s Paradox” II: Questioning the Hart-Tipler Conjecture
by PAUL PATTON on APRIL 8, 2015
It’s become a legend of the space age. The brilliant physicist Enrico Fermi, during a lunchtime conversation at Los Alamos National Laboratory in 1950, is supposed to have posed a conundrum for proponents of the existence of extraterrestrial civilizations.
If space traveling aliens exist, so the argument goes, they would spread through the galaxy, colonizing every habitable world. They should then have colonized Earth. They should be here, but because they aren’t, they must not exist.
This is the argument that has come to be known as “Fermi’s paradox”. The problem is, as we saw in the first installment, Fermi never made it. As his surviving lunch companions recall (Fermi himself died of cancer just four years later, and never published anything on the topic of extraterrestrial intelligence), he simply raised a question, “Where is everybody?” to which there are many possible answers.
Fermi didn’t doubt that extraterrestrial civilizations might exist, but supposed that interstellar travel wasn’t feasible or that alien travelers had simply never found Earth in the vastness of the galaxy.
The argument claiming that extraterrestrials don’t exist was actually proposed by the astronomer Michael Hart, in a paper he published in 1975. Hart supposed that if an extraterrestrial civilization arose in the galaxy it would develop interstellar travel and launch colonizing expeditions to nearby stars. These colonies would, in turn, launch their own starships spreading a wave of colonization across the galaxy.
Full article here:
http://www.universetoday.com/119735/beyond-fermis-paradox-ii-questioning-the-hart-tipler-conjecture/
William, I am a 14 year old female. I am taking 12 grade science. But, you have to think of why it matters. Of course the earth is going to run out of nessesary materials OR, the earth will slowly die, OR the sun will eventually devour the solar system. You need to think; our civilization as we know it will be gone. Whatever spawned our world COULD re spawn our civilization. We find another planet and live on. Either we use the resources we have left to keep our generations flowing or we die.
Which would you prefer? Life more complex, new things, new planet, new world? Or, nothing left but the artifacts we left on earth or what’s left of it….