This post was inspired by a conversation on Hubski with AlderaanDuran.
Astronomers now estimate that there are 100 billion Earth-like planets in the Milky Way. What implications does this estimate have on our search for intelligent life in our galaxy?
I agree completely. I think Paul Davies said this best when he stated that: "Biological intelligence is a fleeting phase in the evolution of the universe."
I enjoyed the trancension hypothesis video. I think this is far more likely a path than expansion. Thanks for the introduction to this hypothesis.
It is a really attractive idea. I am definitely not discounting it. I just want to see some more evidence to support it!
That path requires far more science and technological advancements than expansion, which is why I believe expansion would happen first. I don't see why both couldn't be done, but the trancension hypothesis relies on a lot of extremely complex energy manipulations and things that aren't even provable right now. We're talking about "living inside of a black hole" or "living in a parallel dimension", or "living in a simulation", right? (Can't watch the video right now cause I'm at work, but I've read about trancension before) That to me seems less likely than simply moving our stuff and people to other rocks around our star, and eventually another star. And as I stated in that last thread, I don't believe that this is the answer to the fermi paradox of why we haven't heard from other intelligent life. There are plenty of reasons we may not have heard from them. Number 1, we aren't listening or looking for the right signals and may not even be able to comprehend how other intelligent species communicate. Number 2, they might be purposefully ignoring us until we're actually out in space exploring ourselves and worth talking to.
Enjoy your blog a lot! A few comments below. "If the cultural and technological evolutionary processes that have enabled us to do this are characteristic of intelligent species, we should suspect intelligent civilizations to develop very quickly on galactic scales. We should also suspect them to be very loud." Maybe. Remember radio still has a speed limit. Its easy to say there's nothing out there because we can't hear it, but this only applies IF an intelligent civilization (IC) has been around longer than 100,000 years. We have to have had time to receive these signals. This line of thought also assumes that we can distinguish the signals from the normal, strange noise of the universe. Also, we have only listened to a small fraction of the radio sources in the galaxy. Not a whole lot of data to go off of. Another problem is if ICs have evolved say, only within the last 100,000 years then we SHOULDN'T expect to hear anything for many millennium. What's to say that we haven't simultaneously evolved with other civilizations, in the same galactic time frame? Since our signal has only traveled approximately 70 light years, I don't think its a reasonable assume that other civilizations are ignoring us. Only the civilizations within 70 light years would be able to detect us in the first place. To ignore us, they have to be able to hear us in the first place. The radio bubble is only a MINISCULE amount of our galaxy; an infinitesimally small portion of the potential sources that need to be sampled to provide an accurate measurement. If you haven't read it yet, Carl Sagan & Iosif Samuilovich Shklovsky wrote a book called Intelligent Life In The Universe. It's a thick and awesome read covering all of this and more. Great post!
1) With the first statement when I say "we should suspect intelligent civilizations to developed very quickly on galactic scales" I should have clarified that I meant on the scales of deep time. If a civilization like ours - that is currently experiencing a dramatic increase (over the past few centuries) in technological evolution existed for another 1 million years - I contend that we would be very loud. If you were in the Milky Way you would know about us either directly or indirectly. But your point is well taken. 2) I like your second idea. I suppose that one could best be incorporated into my first point "we are the first." It could also be that we are currently developing on the same galactic time frame. I think it would be really improbable but I guess with 100 billion earth-like planets it is completely possible. Very cool idea. 3) Well I did state in the article that I don't think it is probable that intelligent civilizations are ignoring us. I think this is one of the least likely scenarios. However, under the framework I imagine this scenario - I am talking about a type II-IV civilization ignoring us, so I think they would probably know of our existence even with a tiny radio bubble. Any civilization like this would have circumvented the speed of light barrier (if it can be) and would have a fairly good idea of what was going on in the galaxy. That is why I don't think one exists at the moment (unless they are ignoring us - which I don't think they are). Thanks for your responses. I think the way you think!
What do I think? As interested in astrobiology I think the obvious existence of silent pathways makes the Fermi question "where are they" too unconstrained by false negatives to be "a big question". The "big question" here then remains the age old "are we alone". A silent pathway would be the natural expansion out of a planetary system to the Oort cloud. It is the largest step on the exponential scale of technological and material resources. But it has also the needed material for transportable biospheres without the associated cost and risk of descending deep gravitational wells. As for the astrobiology here: 1. Selection bias. That is asked from a position of selection bias, we _are_ the first if we want to outdefine other intelligences we have observed. More pertinent, biologists use to estimate that language capable intelligence may be as rare a trait as the elephant's trunk. On the other hand they have also come up with estimates based on diversity, which is more or less recovered after mass extinctions. Hence we have independent observable "worlds", and 1 out of 4 (3 large extinctions with land animals) made us. All galaxies got started after reionization, so the parts of MW is about 13.5 billion years old. The first habitable planets aggregated shortly after the first star generation, the oldest known exoplanet is ~ 13 billion years old. We can expect the first life is about as old. Then it takes billions of years to oxygenate a biosphere, which is a prerequisite for complex multicellular life. In our case ~ 2 billion years, but we can see that the oceans were still largely uninhabitable until cyanobacteria also regulated a nitrogen cycle. (Which put a stop to anoxic sulfur conditions.) However, it is believed that the ocean of Europa has been supplied with large amounts of oxygen some hundred of million years after the ice cover formed. This seems to be a generic mechanism for the tidal habitable zone of gas giants. And the biospheres of ice moons are easily 10s of times larger than terrestrial oceans. So early intelligent life is most likely found there. 2. Life span of species. Typical lifetime of mammal species is ~ 1 million years, and Homo seems to lie there. 5. Biospheres. There are two viable cosmological economies, given the distances and the universal speed limit: Information barter and colonization. As I showed above, Oort cloud colonization is likely and means silent dispersal. In any case, colonization means dispersal: population genetics shows that you need one crossbreeding/generation to keep a population from speciation. (Regardless of the size of the population, funnily enough.) [Wormholes break general relativity with their closed timelike curves, so they can't exist - or the universe would have exploded. Alcubierre is a viable GR solution but can't be used. If such a solution is created going FTL there is no way to put mass there to go FTL, since we can't break the universal speed limit for massive particles in the first place.]
To clarify, the oxygen of gas giants comes from their radiation belts affecting the surface ice. Jupiter is extremely large, and it may be that more typical giants supplies less. Also, there are at least 2 hominids that have become ~ 2 million years old, A. afarensis and H. erectus.
When this issue is raised, it makes me wonder how absurd our idea of "intelligent life" might be. We assume that we're intelligent because we're self aware and we use tools and we build stuff, right? But the "self aware" thing is arguable. How self-aware are we on the self-awareness spectrum? Our senses are pretty limited. Our grasp of the physical universe is nascent. Our scope of observation is laughable, right? So what frame of reference do we have to work with in terms of looking for intelligent life? Seems like if we're talking about life as intelligent as we are at our current juncture, the chances are pretty slim even if several million such peoples populate other planets. Problem being, we're not quite intelligent enough. So are we talking about beings more intelligent than us? Well, if they're substantially more intelligent, then would they allow themselves to be noticed, or would they have recognized that as a bad idea? And if they allowed themselves to be noticed, would we even recognize them as intelligent? Would we recognize them as beings? Or would it be like a beetle trying to conceptualize an octopus within the rubric of "beetle-ness?" I suppose eventually (or, what, immediately?) we'll have advanced enough observational tech to at least recognize the planets best suited for our specific style of organic intelligent life. From there, though, it's still a far cry from actually discovering that life within the right time frame with limited technologies.
Great comment fuffle. I agree that if intelligent life exists at far more advanced stages than us they will be incomprehensibly more intelligent. And as Paul Davies said, they will definitely be post-biological. As such if they did not want to be observed, they could easily achieve that goal. And it is even possible, as you pointed out, that sufficiently advanced civilizations would produce patterns that we can't detect or make sense of. I list both of those possibilities as scenario 4.
"advanced" and "stages" sound like text version of this image.
I see no reason to believe those constructs.
We must use some type of categorical language to explain beings more intelligent and civilizations more complex than our own. It is like telling a paleoanthropologist that Australopithecus afarensis wasn't really a species but a continuum of genetic information that - for a time - was similar enough to produce viable offspring with other similar beings. Of course paleoanthropologists realize this - but they still must categorize the species and attempt to understand a rough time line for its existence.
but that is interpolation. Positing future "stages" and "advancement" requires a extrapolation of the next stage and supposition of what goal is being advanced towards. There is enough danger in doing this with scalar variables (a polynomial expression that describes 20 years of data points will almost never describe the next twenty. unless you are lucky enough to have collapse or run away growth right after the end of the data.)
when your model is a n-dimensional complex of nested Lotka–Volterra equations (like evolution and technology seem to be.) It becomes -what is the word for impossible that falls just short of the whole hog? impossible - Δ. The branch from Lucy to us only seems straight because of pruning. I can not think of a darwinistically feasible goal other than adaptation to a niche and we don't know the niches of the aliens.
I would also like to point out that technology does not work towards goals in those terms. Technology that is lasting tends to be created to solve immediate or somewhat immediate problems, and then is adapted to later problems. Look at rockets, to keep with the space alien theme. Rocketry started off as a form of entertainment first with crude fireworks in China, though it quickly became weaponized. Modern rockets have the Germans to thank for their existence, and those rockets were developed as long-ranged bombs to spare the vulnerable Luftwaffe from dangerous bombing runs. They weren't designed to have people in them. A couple decades down the line and you have people strapped to the front of a rocket landing on the Moon, using computers that would one day evolve and merge in to phones, which are further changing to integrated communications tech if Glass takes off on the scale Google hopes. Nobody who designed the cell phone looked at it and said "I'm building this so that in the future people can have a camera on their glasses." They looked at a phone and went "man what if you could carry this?" You can generally extrapolate on trends in technology; decreasing weight, increasing battery life, increasing power, increase screen size, decreasing environmental impact. Predicting what things will be like in the future is impossible, even if we're only talking about the next 5 years. Once an idea like the cell phone or the computer is released to the general public, it goes beyond the minds of its creators and changes in to something totally different. There's no unified goal because the technology is not being developed by a unified structure. Its just happening, and nobody can really tell technology as a whole which way to go. That just happens based on the desire of society in general at the time.
general agreement. I would not bet on the lessened environmental impact at unit scale it happens but in aggregate tech tends to increase resource use or at least has so far.
Seems like kind of an arbitrary thing to take issue with, man. I think we can agree that the above graphic lays out an overly-simplified/fabricated view of how we got to where we are. But I don't think it logically follows that we can't or shouldn't assume that our current "stage", as a whole, is more "advanced" than the "stage" ape-like creatures inhabited however many hundred thousand years ago. As such, it doesn't seem outrageous to chew on the notion, no matter how abstractly, of how an intelligence more "advanced" than us would present itself. Anyhow, in this case, it seems like we're all saying more or less the same thing: alien intelligences may be so alien, either in their adaptation to an alien niche (as you put it, I think) or in the nature of their awareness/intelligence that we may not even be able to identify them as intelligent, or even beings, for that matter.
right right the ladder of life is bad enough when looking back using it or similar thinking to look forward is meaningless.
The only thing we would know for sure about a species that flew to earth is that they are better at spaceflight than us it would tell us nothing about their other technologies, interests or "morality". The last paragraph is my thought exactly.
http://gutenberg.net.au/ebooks06/0601101h.html read the martian bits.
I don't agree with you on this. Technology tends to be interdependent on other technologies. Thus i think it would be totally plausible to be able to determine something about the species other then they were better then us at flight. At the most basic level assuming they had flown to earth we would know they had a mastery of space flight and potentially aerodynamics (assuming they landed). This would mean they would have to have mastered certain areas of Physics and thus have an understanding of the areas of mathematics necessary to understand this. In addition most modern engineering problems require large mathematical solutions which would also suggest for advanced space flight they would also need some sort of high speed information processing / simulation capabilities i.e. they developed and discovered some form of computing. I've only written a short synopsis but there would be a ton of other areas they would likely need to have advanced in as well such as material sciences (to handle vacuum, re-entry, strong acceleration), biological sciences (assuming craft had passengers, if it was artificial or a "drone" then this links back to my point on computer development)
Unless they did not do it how we would do it. My whole point is the tech is interdependent don't have the wheel don't get the pulley etc. The new world did not apply the wheel but somehow figured out road building irrigation running water etc. So if I see a paved road should I assume wheels? In a similar way aliens visiting only tells us they can visit. It implies a lot of stuff but it only tells us one thing. There seems to be lot of projection in what you have written. I partially cede that some tech may be inferred but only in a general sense we know nothing about their physical requirements or limits. We don't even know that mathematics is the only way to arrive at tech. (actually if you look at the history of the jet engine it does not seem to be true) As for moral and ethical "advances" I assume you agree that can not be inferred at all.
I am not trying to posit that I know what an advanced alien civilization looks like. I don't believe I could possibly know their behaviour, morphology, communication methods, etc. That is the whole point. Your quote does not contradict what I am trying to say. By "stages" and "advancement" I am referring to complexity of system organization and energy extraction. The reason why this is plausible to discuss is because we do know the niche that hypothetical multi star-system civilization would inhabit (unless they leave or exploit areas of space we are currently unaware of - which of course is possible).