Be careful what you wish for. It may sound exciting to live in a dense stellar neighborhood, but there are downsides. For example, extremely close approaches by other stars would be much more common. Such encounters could mess up the planetary orbits, causing all kinds of ruckus. And then there’s the elephant super massive black hole in the room.
Right, and that’s largely the point of the paradox.
The point is; based only on our understanding of physics, chemistry, biology, cosmology etc, we don’t know of any reason why our galaxy is not buzzing with the tech and culture of thousands of intelligent civilizations. Perhaps millions.
Yes, we can posit potential reasons why that may be the case. But we don’t have data to tell us which, if any, of the explanations are among the correct ones. It’s a fascinating gap in our current understanding.
However bombing is itself a very risky thing to do. So I don’t think the game theory logic of this totally stands up.
Plus your summary of the dark forest here doesn’t entirely make sense, as being seen is as dangerous as sending signals (indeed essentially the same thing).
They aren’t too far away.
Admittedly, there still are great difficulties in travelling interstellar distances. A micrometeorite of the kind that have been rattling the JWST would be deadly. But I don’t think engineering challenges are very plausible paradox solutions – if humans are typical of sentient intelligences, then we’d expect problems like this to be solvable in mere centuries, millenia max.
Regarding our star being out in the boonies, I don’t see the relevance. If the center of the galaxy was awash with intelligent species then we’d see evidence of that, we don’t need them to physically come to us.
And, if species develop tech that can travel between stars in the center, then they can travel between stars in the arms, and for the same amount of energy to boot.
Sure. But in the meantime, we don’t know why it’s so apparently quiet.
I think Kurzgesagt did a video on this topic recently. The conclusion that they came to was that anything below the industrial revolution would be undetectable, but anything after that, would be.
But, in general, this hypothesis makes the paradox worse. If intelligent species are common enough and/or spread out enough, that one has even made its home here previously, then it’s really weird how quiet the galaxy looks now.
This is interesting stuff, to me, anyway. I may be misunderstanding what you seem to me saying. Can these compounds be detected with a spectrometer or something like it? Is this a capability we already have and already use to check for life on every exoplanet we can or is it just now with the JWST that it has become possible? Why couldn’t earlier observation platforms make the same analyses on easy to “see” closer planets??
Is it a matter of being able to observe farther away galaxies? I would wonder what makes further away stars more likely than closer ones to have life. Would their age affect this?
Good post.
If I can believe a ramdonly chosen non-crazy web site, no dates have been found on how old the Lowland streaked tenrec species. However, it surely has existed only a fraction of one percent of the time earth has been in existence – and probably – expecially if we care not just about how the bones look, but in terms of current behavior – a tiny fraction. The streaked tenrec doesn’t seem to be currently on lists of endangered species, but Wikipedia says it is hunted for food, so there may be a race to see which species dies off first, the streaked tenrec or homo sapiens.
We know that scientifically talented species are extremely rare. On our own planet, there are nine million species, and, hardly ever, in five billion years of plantary history, has even a single scientifically talented species existed. What we can’t do is put a number on that extreme rarity with respect to other planets.
My hypothesis is that once a species invents birth control, it doesn’t last long. But even if intelligent species last an average amount to time, the chances that we and, say, the intelligent species of the Alpha Centauri system, would be around at the exact same time is low.
The more mathematical one is, the more one tends not to be impressed with really, really big numbers. Numbers can get really small (very close to zero) as well and can overwhelm your really, really big numbers.
The problem with believing there is much intelligent life out there is that there is no signs of it. You would think that one would see galaxies ‘going dark’ as races get more energy hungry…or even completely dark galaxies radiating only in infrared. Now, you can argue that maybe races don’t go the Dyson Swarm route…but there should be SOMETHING. You can argue that (bring up many ‘solutions’ to the Fermi Paradox) but it is hard to believe that if intelligent life is so common and has been around for billions of years that there should be evident everywhere.
I think the “Great Filter” hypothesis to the Fermi Paradox is likely valid. Essentially it means there is one (or more) extremely unlikely events that intelligent life has to go through to develop. What this means is your very very very large numbers are being countered by an even smaller-close-to zero number that when multiplied together you get a very small number.
Isaac Authur - a great futurist/science Youtuber also believes this is most likely…he hypothesizes that there is one intelligent civilization around per supercluster - which is many many millions of galaxies.
What are the filters? Off the top of my head -
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Life is extremely hard to autogenerate. This is countered by many saying that life seems to have begun on Earth as soon as it was possible so life is common. They may be right. However, if life was extremely rare then it ALSO would start as soon as possible because it only has a very small time to get going and if it did, it most likely had to start as soon as possible. Earth is near the end of it’s habitability and so intelligent life developed close to ‘the end’ which fits this.
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Multicelled life is extremely rare. - I am not an expert but it appears multicelled life was kind of a fluke event. It took like 2-3 billion years for it to happen. People are used to ‘deep time’ but 3 billion years is beyond deep time. It is more than 20% of the time back to the big bang!
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Intelligence is extremely rare - it certainly appears that way on Earth so far.
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Developing from intelligence to technological civilization is extremely rare - You might think it should happen as a matter of course but would it? Dolphins have no limbs to use to build…plus they are in water so fire is very hard. Speaking of fire - if Oxygen was even a bit higher or lower than now fires would be extremely dangerous or burn lackluster. Humans are also weird - we are very social for a large animal. We tend to keep ‘childlike’ qualities as adults and avoid inflexible routines and keep curiosity. Isaac Aurthur even brought up something as simple as our ‘disgust reflex’ being just right…it helps us avoid disease…BUT we can still do things like reuse dishes after washing. Imagine an intelligent species with a disgust reflex higher as to find it impossible to reuse dishes. That ALONE could keep them from being technological.
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Some near future event is the great filter - like tech civilizations create climate change so bad that their planet has a runaway greenhouse effect like Venus. There could also be some technology that leads to oblivion.
So…NO I don’t have to accept your hypothesis that technological civilizations abound.
Thanks for the response.
I’m not making an argument. It just puzzles me that the result of the process of life is sustained, but the process that created it is not. If the conditions required to create these molecules is a dot on the timeline of a planetary system, followed by an extended period of benign environment, then life may be vey rare indeed.
It’s worse than that. The central hub of our galaxy is likely to be the location for numerous high-energy events, such as supernovae, stellar collisions and gamma-ray bursters, which would probably make the life-expectancy of any biosphere in that volume short and brutish.
The precise conditions for abiogenesis are currently unknown, but it seems very likely that abiogenesis cannot easily occur after an oxygenation event. So we don’t see new biogenesis on our planet, for example.
Note that (in the case of the Earth, at least) the oxygenation event was a direct consequence of the emergence of life, so it may be possible for the correct conditions for abiogenesis to occur on other worlds after many billions of years of lifelessness.
Here’s Anders Sandberg, Eric Drexler and Toby Ord with a mathematical analysis of the Great Filter hypothesis, and their conclusions are quite pessimistic.
While I am pessimistic about there being much intelligent civilizations out there, I do think that will change a bit going forward.
I think the great filter hypothesis is right…and, just my gut no other reason than my gut, tells me that the filter is technological civilizations arising. I think it is a great filter/very rare.
However, one of the reasons is rare is that it takes so long to develop. Look at Earth. Why didn’t the dinosaurs develop one…or 2…or 3…
SInce it takes so long to develop and we are around probably the largest star for it to happen (A yellow dwarf)…and we are here it means we likely beat the odds. However, other stars smaller than our sun, , primarily Orange Dwarfs, will last longer. This means in the future more will develop.
While I don’t think tech civilizations will sprout like weeds, I do think more and more will come as time goes by.
So…I guess my ‘solution’ to the Fermi Paradox is we are one of, if not the, first.
I don’t think that paper really says anything though.
Firstly, while I’m aware that the Fermi paradox is often summarized as being the expectation that sentient life should be common, I think this is a misconception / non-deliberate straw man. Because, when we look at the original comments by Fermi (and actually, other scientists before and after that) they are usually asking the question rather than making any kind of claim.
So, all the various analyses that do nothing but challenge the assumption of intelligent life being common…are completely pointless and unknowingly fighting a straw man. (That includes the channel Science Asylum, which is one of my favorites but really flunked on the Fermi paradox IMO)
But secondly, IANA statistician, but an analysis based on putting distributions within the unknown space of the Drake equation looks extremely shaky.
The number of terms in the Drake equation is pretty arbitrary, any one of them could be broken down into dozens of separate questions, or aggregated up into single terms.
If we do the former, then the chance of ETs massively goes down, since many “sub-questions” are more uncertain than their parent question, so the space for random distributions increases. The whole approach looks suspect to me.
True, but the conditions for abiogenesis must overlap with the conditions that support life. Of course they could be sharp physical margins like thermal vents.
I think we don’t need to posit that any civilization will kill itself off before expanding to neighboring stars. I think we only need to posit that any civilization sufficiently expansionist to spend its time and resources doing any such thing (beyond perhaps a couple of spare locations in case the original home gets hit by a planet-killer) doesn’t survive.
It may be the combination of “technologically-oriented intelligence” and “insistence that More is always Better” that’s lethal. Maybe species that don’t believe “there’s no such thing as Enough” survive just fine – but they don’t try to take over the universe.
I strongly suspect that a very large number of other species right here on Earth are conscious; and that many humans are just unwilling to recognize this in species other than our own.
I don’t know that we have a clear enough understanding of what “consciousness” is to either prove or disprove this.
Isn’t it simple enough to posit that space is so incredibly large, and life has a finite ability move at high speeds, that it’s simply irrational to expect that any life on any one planet can traverse the universe?
I mean, let’s say that we get really really advanced as a species, but it remains true that we can never really even approach traveling the speed of light (what with mass and all), and that neighboring civilizations remains thousands of light years away. We’re just never going to get there, and even our strongest signals are just faint noise in the vastness of space.
I think of it like an ant, living in an anthill in some desolate park in suburbia, trying to conceive of other anthills in the world. Simply walking a couple of miles to the school playground to find another anthill is beyond the ant’s abilities, let alone traveling to another continent with its own ant populations. Sure, from our perspective, ants are pretty ubiquitous, but the one ant in the one ant hill is never going to see the evidence.
I don’t think so. At best we could surmise that it is very possible that humans are unique to Earth, with a similar probability of the streaked tenrec being unique. However, my guess is that there are many pathways to a technological civilization that bear no resemblance to the human pathway.
If we were a non-technological species asking if an extraterrestrial technological civilization is possible/probable, then the odds would be lower. But, we are a technological species, so we know it’s possible given the same elements and physics that are not unique in the universe.
Actually, any estimate based on known exoplanets is likely to be on the low side because of detection bias (i.e. a hot super-Jupiter that orbits its star in a week is a lot easier to find than an Earth-sized planet in the liquid-water zone).
The great science writer Willy Ley put what became known as the Drake equation into print several years before Frank Drake. I’m always surprised he doesn’t get more credit for it.
Here’s Drake’s original:
Original estimates
There is considerable disagreement on the values of these parameters, but the ‘educated guesses’ used by Drake and his colleagues in 1961 were:[17][18]
- R ∗ = 1 yr−1 (1 star formed per year, on the average over the life of the galaxy; this was regarded as conservative)
- f p = 0.2 to 0.5 (one fifth to one half of all stars formed will have planets)
- n e = 1 to 5 (stars with planets will have between 1 and 5 planets capable of developing life)
- f l = 1 (100% of these planets will develop life)
- f i = 1 (100% of which will develop intelligent life)
- f c = 0.1 to 0.2 (10–20% of which will be able to communicate)
- L = 1000 to 100,000,000 communicative civilizations (which will last somewhere between 1000 and 100,000,000 years)
Inserting the above minimum numbers into the equation gives a minimum N of 20 (see: Range of results). Inserting the maximum numbers gives a maximum of 50,000,000. Drake states that given the uncertainties, the original meeting concluded that N ≈ L, and there were probably between 1000 and 100,000,000 planets with civilizations in the Milky Way Galaxy.
The sticking point is obviously * f i = 1 (100% of which will develop intelligent life). If that is 1 in 10,000,000,000,000,000,000 than everything is explainable. That still leaves room for 20,000 examples of intelligent life, given the number of stars known in the universe, but makes it exceptionally unlikely that they will encounter one another.
This is true, but the fact remains that we still haven’t found any terrestrial-type planets that bear more than a slight resemblance to Earth. They are either too big, or too close or too far from the star, or are likely to be tidally locked. One in ten thousand is quite optimistic.
But that presupposes that life can only emerge on Earth-like planets. There may be a much wider range of environments that can support life, and intelligence; just don’t expect any tenrecs, or any humans, or anything we can easily recognise.
Not really, if you consider Drakes equation:
You are are correct the fp term is pretty high, there a lot of planets out there. But it would only take one or two other terms to super low to cancel that out and come up with a N value of under 1.
E.g. if the chance of life developing on a planet fl was the same as the chances of a specific arrangement of a deck of cards, which seems like a reasonable guess to me given all we know about abiogenesis, then you have a term that is 1 in 10 to the power of 68, plenty low enough to bring the final value to less than one.
Given that I have personally never understood why this is called Fermi’s Paradox. It’s not remotely paradoxical.
From the OP question, I would say it’s more of a mirror statement: that at this point it may be “kooky” to affirm there can’t possibly be other life and civilizations, whether separated in space or time.
Which IMO is different from saying that there could be, or that nothing prevents it being so, “…but…”, that you can’t categorically assert either as a fact that there must be “massive amounts of intelligent life”, because it’s a probability you may never get material proof for.