The ancient search for life out there

The discovery of five planets around 55 Cancri, a sun-like star with one of the planets in the habitable zone brings the question of the Fermi Paradox even more into the forefront.

Solutions to Fermi's paradox often 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.

1. 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 descendants 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.

2. 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

3. 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

http://zebu.uoregon.edu/~js/cosmo/lectures/lec28.html

Earth is the nicest place in this solar system.
David

When earth's rotation causes me to face Uranus, I can only hope I'm upwind.

O, shame on u !

I'm as nasty as a coarse bastard file!

The best response to the alleged "Fermi's paradox" is that it is hopelessly naive.

- Based on the assumption of the manufacture of Bracewell-Von Neumann probes
- Based on exponential growth
- Based on the age of the universe in which life could have arisen

Do you have the math showing exponential growth of Bracewell-Von Neumann probes to be false in the time in which life could have arisen?
Do you have a rationale to presuppose an alien race would not build Bracewell-Von Neumann probes?
I have the flu do you have any suggestions?

I like the concept that really advanced civiliztions graduate from energy wasting "radio signals". Omni-Radio is really a primitive means of long distance communication and we are gradually growing out of it.

David, I agree. Earth is the nicest place for earthlings.

BTW, it seems that another condition for advanced life (the kind that flies space ships to other planets in other solar systems) is that they go through some kind of industrial revolution and evolve cultures that motivate them to travel. I suspect a lot of projection there.

I concur.

My objections to the alleged Fermi "paradox" is that it is hopelessly naive in a variety of matters. I have no objection to the notion that advanced technological civilizations would send out probes, or that those probes could not be constructed so as to reproduce themselves. That, however, has nothing to do with Fermi's alleged paradox. Fermi asked, "So where are they?" Probes could have visited our star system numerous times, and we would not necessarily have any evidence of it. Alluding to Bracewell-Von Neumann probes is a non-sequitur with regard to Fermi's supposed paradox.

Otherwise, the alleged paradox is naive because it assumes so many things about the civilizations which would have by now spread through the galaxy in Fermi's opinion. It assumes that it were a simple matter to send out colonizing missions. It costs enormous amounts of materials and energy (and therefore, in our terms, enormous amounts of money) just to lift a handful of people out of the gravity well, the "mother well," of our home planet. For a colonizing mission to be successful, it will need far more than a handful of people. Even if a colonizing mission were sent out with frozen ova and sperm of the sentient species, and any plant or animal species upon which they depend, enormous amounts of material and energy would be needed to preserve and sustain those "seeds," and a significant number of people would be necessary to supervise and maintain the systems, even if they relied upon "robot" systems--which would themselves still be need to be supervise and maintained. Over any significant distance, either those waking supervisors would need to reproduce and produce new supervisors, or would have to be in sufficient number that they could stand years long watches, with the "off-watch" people kept in a form of suspended animation. That again implies huge amounts of resources, material and energetic, which would need to be lifted out of the mother well, and lifting them out of the mother well would require enormous resources of material and energy.

In the one example we have, our planet, no single nation has the necessary resources to accomplish such an end, without nearly impoverishing its people to attain the goal, and human nature tells us that the people being left behind are unlikely to long accept that poverty for the sake of others whom they will never meet, and who will have no necessary allegiance to those who made the sacrifice for them.

So the alleged Fermi "paradox" naively assumes that any technologically advanced civilization would necessarily be able to command the total resources of the home planet, without regard to any objections on the part of the population, in order to regularly send out colonizing missions. That is naive to anyone who hasn't got their head in the clouds of science fiction, the only realm in which it is assumed that the members of any advanced civilization would be a united species striving eternally toward a goal which had no benefit for those who sacrifice toward that end. There is no good reason to assume that other technologically advanced civilizations will be unitary and free from the imperatives of practical politics--so it is a naive assumption.

As for exponential growth, that is another silly science fiction based assumption. The present population of this planet is in excess of six billion individuals. If it were determined that the planet would have reached a saturation point at eight billion individuals, at which point we would begin destroying our environment faster than we could produce the resources necessary to sustain us, is anyone so foolish as to propose that we could solve that problem by colonizing other star systems? All the objections about lifting a sufficient amount of resources out of the mother well for a colonizing effort are simply increased by orders of magnitude in contemplating the removal of a proportion of the population sufficient to achieve a population sufficiently low to maintain our current resource producing systems. Once again, it were naive in the sense of practical politics to think that those to be left behind would be willing to make the sacrifice to benefit those who were leaving. Interstellar colonization as a means of overcoming overpopulation is just another naive science fiction pipe dream.

No aspect of the alleged Fermi paradox can escape what we know of as human nature. The intelligent members of an advanced civilization cannot be any more reasonably expected to make long-term, debilitating sacrifices for the benefit of strangers who are likely never to repay the debt than it would be to assume that humans as we know them would be. Fermi can't have given much genuine practical consideration to the implication of the question "Where are they?" I suspect it was an idle question, and that it has gotten a lot more attention since it was reported than the amount of thought Fermi actually gave it.

Automated exploration is completely plausible, and rejecting the alleged paradox of Fermi does not argue against automated exploration. Simply put, we would have no way of knowing that there were now, or ever had been automated explorers out there, or if any had ever visited our planet. As recently as a century ago, an automated explorer could have visited this planet, and we would have had no way of knowing the event had occurred.

As for your influenza, i would suggest that if you weren't so snotty about this and other questions to begin with, you'd be far less vulnerable to the disease.

This is exactly the kind of thing i mean when i say the alleged paradox is naive. It appears to me that Fermi gave not a moment's thought to the "human" aspects of the question.

Thanks for the posts Set, I'm not sure what to think yet so I'll give it some thought.

Hi Set,
Your views are focused on present-day technological assumptions as they apply to interstellar space travel of short-lived organic life forms. Being a bit a of a science and SF guy I am well aware of these present day limitations.

I make no such singular argument when I refer to the Fermi paradox. I see many others don't either when they refer to the Fermi paradox. I quoted one such in my earlier post.

Full scope of the problem and the strict definition of the Fermi paradox aside however you do go on to say that "automated exploration is completely plausible", but do not explore two reasonable possibilities:

1) I see no inherent reason why RF or other signal-modulated interstellar radiations would not have had the time, based on the age of the universe in which life could have arisen, to have been radiated to our corner of the Milky Way. Yep I am aware of the inverse square law of energy propagation, which naturally enough, leads to point 2.

2) I see no inherent reason why RF or other signal-modulated interstellar radiations would not have had the time, based on the age of the universe in which life could have arisen, to have been radiated from Bracewell-Von Neumann probes as they exponentially grow in numbers, and exponentially mobilize starting from their home source. Bracewell-Von Neumann beacon-probes would be a better term here.

It's understood that SETI has not found RF or other signal-modulated radiations that would confirm 1 and/or 2. At least SETI has not yet!

I am aware of the arguments as to SETI's scanning limitations, and of the scope of the task, but those arguments do not necessarily negate the multi-band efforts that could have been used to promote 1 and/or in particular 2.

What argument you do or do not make with regard to the alleged Fermi paradox are meaningless. Fermi asked "Where are they?" One needn't tie oneself in speculative knots about the probability of favorite science fiction "wouldn't it be nice" propositions about technologies which do an end-run around the cosmic speed limit (186,282 miles per second). If there are other technological civilizations "out there" which have that problem licked, they could be zooming all over the cosmos--and we don't have the technological means to detect their presence.

The great logically naive aspect of the so-called Fermi paradox is that it assumes that because the human race in 1950 (when Fermi made his remark) was unable to detect other civilizations, they must not be there. I am not asserting that other technological civilizations are or are not there, i'm just pointing out that the case is founded upon a flawed premise. Fermi could have answered his own paradox by rephrasing it as "Why haven't we detected them?" In that phrasing, a very sound objection that there is no paradox arises from simply pointing out that "they" could be there, and we may well have no way of knowing it.

This objection also applies to RF and microwave "signatures" of automated probes. Although i said i have no objection to the concept of automated probes (and i am not back-peddling here, i can easily conceive of sending out probes, and of going to the enormous expense of sending out self-replicating probes), the same objection applies to them. Unless one alleges a means of communication which sidesteps the speed of light restriction, there is little reason to assume that any civilization is going to send out a probe that will be unable to provide any useful information for years, tens of years, hundreds of years or thousands of years. In fact, if one is willing to wait thousands of years to get incomplete information from a probe, there is every reason to wait those thousands of years for the probe to return, and to be able to access all the data which the probe can provide. Of course, as FM alludes to, it is entirely possible that advanced civilizations would use focused RF or microwave communications which we would not detect unless we coincidentally found ourselves in the path of the signal. But the objection about our ability to detect said probes applies just as does the same objection to our ability to detect the presence of the members of any such putative civilization itself. If any technologically advanced civilization has found a means of overcoming the light speed limit, we would not possess the means to detect the signal.

Your point one can be answered by the same remark i made with regard to our having been visited by such probes. We might well have been visited by one or more automated probes, but have no way of knowing that that were the case. By the same token, automated probes might have used the primitive and imprecise and wasteful method of universally radiated RF or microwave communications to report to the originating civilization, and at the time that the signal passed the region of the cosmos which we inhabit, we were not able to detect it. Microwave signals go bounding around our globe all day, every day. One would not, however, expect a Bushman in the Kalahari Desert to know that those microwave signals were ubiquitous.

If, however, such signals originated from automated probes, given the small order probabilities which are advanced for technologically advanced civilizations (even thousands or tens of thousands of them in this galaxy don't make for very much signal traffic within the vast volume of space which we have to consider), there is no good reason to assume that such signals would be as ubiquitous as are microwave signals between transmitters and receiver on our globe. There is, in fact, every good reason to assume that they would be relatively rare.

So, either these probes have been here, or sent signals, and we were at the time unable to detect them, and they have left no evidence--both of which possibilities are very good. Or, they rely upon technology which it is beyond our means to detect.

But as for the alleged paradox of Fermi, it was predicated upon an assumption which had nothing to do with probes. It was predicated upon an assumption that such civilizations would spread throughout the cosmos, and that therefore we ought to have detected them by now (the now being 1950, when Fermi made his remark). That was naive because the means to detect their presence were so primitive almost 60 years go. It was naive because no one was committing resources to look for "them." It was naive most of all, however, because it ignored the realities which will necessarily limit the efforts of any technological civilization to spread throughout the cosmos. Even were we to send out 500 expeditions, each comprising 1000 individuals every year to establish colonies in this galaxy, we would have to impoverish every other human activity to accomplish that end, and we wouldn't even be reducing the population of the world by a significant fraction. The crude birth rate is presently 20.3/1000 population (source at Wikipedia), which is a factor of the number births divided by the average life span of the population. Do the math yourself--that's more than 120,000,000 annually, and the scenario i outlined only rids us of half a million individuals per annum, which even when combined with the death rate would not represent any useful decrease in the population of the planet. The concept of interstellar colonization as a means of population control is laughable.

Therefore, one is lead to consider why a technologically advanced civilization would send out colonizing missions. This immediately raises the question in my mind of why the individuals who comprise such a civilization would endure the sacrifices necessary to launch continual missions with any reasonable prospect of success when there is not profit in it for them. It cannot reasonably be alleged that such colonizing efforts would make any significant contribution to population control. For our own purposes on our planet, we'd have to launch well over 100,000,000 people each year to have an appreciable effect on population control, and no one is likely to want to go unless there is a very good prospect that they would survive the journey, and the colonization effort upon arrival. Give a little thought to the enormous resources in materials and energy which would be required to put well over 100,000,000 people into interstellar space each and every year, and then ask yourself just how reasonable the proposition is.

For whatever other reason one could allege for sending out colonizing missions, you are then faced with the question of why those left behind would be willing to see their planets resources used in such huge amounts for such a purpose. To quote a silly movie of which i am found: "I see no profit in it for me." That attitude would be likely to govern the response of the majority of individuals in the originating civilization.

Upon that basis, i conclude that it is only highly probable that such civilizations would send out probes. I have already explained why i don't consider it reasonable that we would know if there were probes zipping all around the cosmos even as we speak. So, because it naively assumes (even if that were not his intent) a great many improbable things about what passes for human nature among other sentient life forms, if any other exist, i find the "Fermi paradox" to rather silly.

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As for science fiction, people who are fond of it, and read a great deal of it, often seem not to give proper weight to the word fiction. When i was a teenager, and in my 20s, i was very fond of the genre, and experienced that marvelous "gee, wouldn't it be great if" sense of wonder and delight at the implications of science fiction. But when i was in my early 30s, i happened to re-read Heinlein. That shattered everything. My initial response was disgust at Heinlein's racism, sexism and elitism. But beyond that, it lead me to reconsider science fiction in a new light, and to realize that about 99% of it relies upon assumptions about technological advances which don't just stretch credulity, but positively violate the laws of physics as we know them. It ruined science fiction for me as an entertaining form of fiction. I now only read science fiction for the same reason that one would read any other fantasy literature--if it is done by a good story teller. On that basis, i'll even read or re-read that old faker Heinlein.

On the basis of the laws of physics as we know them, it seems unlikely that any technological civilization would ever make very many, or any very large effort to colonize other star systems--"human nature" and the enormous cost in energy and materials to get the necessary resources and individuals out of the gravity well mitigate against it. At the same time, alluding to wonderful advanced technologies which will obviate those problems, and make it possible for colonizing missions or even simply probes to reasonably stay in touch with the originating planet leads us back to the problem that our own technological sophistication is not such that we would be able to detect any such ventures on the part of another civilization.

I don't even consider SETI in such thought exercises. We simply don't commit any more than laughably small resources to such efforts.

Maybe "they" are "out there"--maybe we're just deaf and blind.

I'll think about your latest post and respond, thanks!

Here we have the makings of a Bare Assertion Logical Fallacy given you provide no evidence my argument is meaningless.Here we have the makings of a Straw Man Logical Fallacy given I did not make this claim.

I'll endeavor to reply to the rest of your above post, should we move ahead on these two points.

Chumly,

How would you ever make a post if you could not use the words, "Straw Man Logical Fallacy"?

I'll kill a few Intrepids with one stone:

Your post is a non sequitur logical fallacy (understandably it could be in part or in whole as humor).
Your post is a rhetorical use of the bare Assertion Logical Fallacy.