The Fermi Paradox has been resolved

StewartR

StewartR

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This is possibly the most significant piece of news, ever: Mankind is quite probably the only example of intelligent life in the universe.

Detailed paper here: https://arxiv.org/pdf/1806.02404.pdf

Quick summary:
Sandberg / Drexler / Ord said:
We have seen that a Fermi paradox arises if we combine a high and extremely confident prior for the number of civilizations in our galaxy with the absence of evidence for their existence. The high confidence that causes this clash typically results from applying a Drake-like model using point estimates for the parameters. These estimates, however, make implicit knowledge claims about processes (especially those connected with the origin of life) which are untenable given the current state of scientific knowledge.

When we take account of realistic uncertainty, replacing point estimates by probability distributions that reflect current scientific understanding, we find no reason to be highly confident that the galaxy (or observable universe) contains other civilizations, and thus no longer find our observations in conflict with our prior probabilities. We found qualitatively similar results through two different methods: using the authors’ assessments of current scientific knowledge bearing on key parameters, and using the divergent estimates of these parameters in the astrobiology literature as a proxy for current scientific uncertainty. When we update this prior in light of the Fermi observation, we find a substantial probability that we are alone in our galaxy, and perhaps even in our observable universe (53%–99.6% and 39%–85% respectively).

’Where are they?’ — probably extremely far away, and quite possibly beyond the cosmological horizon and forever unreachable.
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The bottom line is that we just don’t know.
The optimist in me just looks at the vastness of the number of stars in the universe and probable proportion of those that have planets etc etc (the Drake Equation).
It really is a fascinating conundrum.
 
Ricardodaforce said:
The bottom line is that we just don’t know.
The optimist in me just looks at the vastness of the number of stars in the universe and probable proportion of those that have planets etc etc (the Drake Equation).
It really is a fascinating conundrum.
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I like the concept of the Drake equation, but the numbers plugged in always felt way off to me.

Is there life out there somewhere - probably
Is it something we would recognise as life - possibly
Is it 'intelligent' as we would consider it - maybe
Will we ever discover/meet it - almost certainly not
 
As that Mr Clarke said

Two possibilities exist: Either we are alone in the Universe or we are not. Both are equally terrifying. It has yet to be proven that intelligence has any survival value.
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BTW I've not read the paper yet but to say it has been "solved" because they have run some numbers saying (other) intelligent life is a very very long way away doesn't seem very satisfactory to me. I'm not sure what is news about that.
 
JonathanRyan said:
BTW I've not read the paper yet but to say it has been "solved" because they have run some numbers saying (other) intelligent life is a very very long way away doesn't seem very satisfactory to me. I'm not sure what is news about that.
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I think you misunderstand. The problem has not been solved, but the paradox has been resolved. There is no paradox.

The paradox arose because, whatever semi-plausible numbers you plug into the Drake equation, you end up concluding that the expected number of civilisations in the galaxy / universe is rather high. Basically, the chances of life evolving and of intelligence evolving on any given planet might be vanishingly small, but the universe is such an overwhelmingly huge place that tiny probabilities x 10^24 stars = a lot of civilisations, many of which would be much much older than ours and inconceivably more advanced. But we don't see them. So the paradox asks: Where are they?

The new analysis says there is no paradox because the way scientists have been approaching the Drake equation for the last 50+ years is all wrong. The maths and logic are a little hairy, but can be easily illustrated by reference to a simple analogy. Suppose "God" created the universe and flipped a coin to decide how many alien civilisations there would be. Heads it's 10 billion, tails it's none. Then several billion years later here we are trying to make sense of it all, and our analysis says that the expected number of civilisations is probably about 5 billion, which turns out to be correct. So if the expected number is 5 billion, where are they? The reality is simply that the coin came down showing tails, and there are none. And that's basically what's happening in the Drake equation. Although all our plausible estimates give expected numbers which are large, if you run Monte Carlo simulations and sample parameter values from the hypothesised ranges, then the distribution of answers is very wide and - critically - an awful lot of the solutions come out at zero.

So the news is that the Fermi paradox isn't really a paradox. We don't see any other civilisations because there aren't any. (Or maybe there aren't many and they're all a long way away.)

I think that's quite big news. As you observed, the question of whether we are alone in the universe is the biggest question there is, and any kind of definite answer would be terrifying. This analysis doesn't provide an answer, but it does show that - contrary to previous beliefs - our being alone is entirely consistent with everything we know about astronomy, chemistry, and biology. That's pretty sobering.
 
Ricardodaforce said:
The optimist in me just looks at the vastness of the number of stars in the universe and probable proportion of those that have planets etc etc (the Drake Equation).
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Me too. I'm optimistic that we are not alone. But I'm not as optimistic as I was yesterday, and my optimism now flies in the face of the science rather than being buttressed by it. We've all been misunderstanding how to use the Drake Equation, and if we do it properly the answers are quite depressing. .
 
I mean it is possible that we are the only intelligent life out there.

It is possible.

It is possible that we are not.

The only certain way to be sure is to visit every single planet. Since we can't do that, then we don't know so it is possible that there are intelligent life out there.
 
StewartR said:
I think you misunderstand. The problem has not been solved, but the paradox has been resolved. There is no paradox.

The paradox arose because, whatever semi-plausible numbers you plug into the Drake equation, you end up concluding that the expected number of civilisations in the galaxy / universe is rather high. Basically, the chances of life evolving and of intelligence evolving on any given planet might be vanishingly small, but the universe is such an overwhelmingly huge place that tiny probabilities x 10^24 stars = a lot of civilisations, many of which would be much much older than ours and inconceivably more advanced. But we don't see them. So the paradox asks: Where are they?

The new analysis says there is no paradox because the way scientists have been approaching the Drake equation for the last 50+ years is all wrong. The maths and logic are a little hairy, but can be easily illustrated by reference to a simple analogy. Suppose "God" created the universe and flipped a coin to decide how many alien civilisations there would be. Heads it's 10 billion, tails it's none. Then several billion years later here we are trying to make sense of it all, and our analysis says that the expected number of civilisations is probably about 5 billion, which turns out to be correct. So if the expected number is 5 billion, where are they? The reality is simply that the coin came down showing tails, and there are none. And that's basically what's happening in the Drake equation. Although all our plausible estimates give expected numbers which are large, if you run Monte Carlo simulations and sample parameter values from the hypothesised ranges, then the distribution of answers is very wide and - critically - an awful lot of the solutions come out at zero.

So the news is that the Fermi paradox isn't really a paradox. We don't see any other civilisations because there aren't any. (Or maybe there aren't many and they're all a long way away.)

I think that's quite big news. As you observed, the question of whether we are alone in the universe is the biggest question there is, and any kind of definite answer would be terrifying. This analysis doesn't provide an answer, but it does show that - contrary to previous beliefs - our being alone is entirely consistent with everything we know about astronomy, chemistry, and biology. That's pretty sobering.
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Thank you - that's a really detailed reply. I'll try to make some time to read the paper as well.

To take your coin analogy though....it's not "tails you get zero". After all we are here. Doesn't that look instead like flipping a coin 10 billion times? As I understand the paradox it starts by observing that on at least one occasion the chances of intelligent life evolving turned out to be non zero. Looking at the size of the universe, it asks how likely it is that a non zero chance occurs once. Then multiplies up and says "where are they all?"
 
Given the size of the universe its highly unlikely we are the only life around and about.
It would be the one thing I would like to know before the inevitable catches up with me

Love to see how the various religions explain that one, never really got to grips with Darwin let alone aliens
 
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I doubt we're the only life around. I suspect most life will be similar to what was on earth a few billion years ago - moss and lichens or similar. There will be even fewer forms of life that are going to be "intelligent" and of those, how many are going to be contactable?

It is entirely feasible that there are lifeforms similar in advancement as us but are so far away that contact will be impossible, leaving us entirely isolated.
 
It always felt to me like the Drake equation was missing a factor relating to the chance of detectable broadcasting civilisations existing concurrently. For example we only started broadcasting around 100 years ago, millions of other extra-terrestrial civilisations could have come and gone in the previous 13.6 billion years but our use of radio communications simply did not coincide with any others that are close enough to be detected.

If you look at the way our use of radio is going we have gone from a few, strong, transmissions to a vast number of weaker, signals (e.g. WiFi, mobile phone), I don’t think it will be that long before a lot of broadcast TV and radio will be replaced by Internet/WiFi. So there could still be plenty of advanced civilisations out there but their signals are no longer distinguishable from background noise. (Without even thinking about some other means of communication that we haven’t discovered yet)

There is no evidence that the dinosaurs developed radio however they were remarkably successful and existed on the planet much longer than we have. If they hadn’t been wiped out by a random asteroid we might never have evolved, or it might have taken another X million years for us to get our chance. So suppose a broadcasting civilisation pops up every 50 million years and broadcasts detectable signals for 200 years, my stats is not good enough to work out the probability of 2 such civilisations exiting concurrently but it’s got to be less than 1 in 250,000. But taking a very simplistic view, we would typically have to search for on average 125,000 years before we detect another civilisation. (My maths is probably all wrong but you get the idea...)
 
sirch said:
It always felt to me like the Drake equation was missing a factor relating to the chance of detectable broadcasting civilisations existing concurrently.
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I get your point, but I think you're missing a bigger one. What is the technological prowess of a civilisation which is, say, 1,000,000 years or 1,000,000,000 years more advanced than ours? It's almost unthinkable. Look at how thoroughly we've transformed our little corner of the universe in only a few hundred years, and extrapolate for 1,000,000,000 years. We wouldn't need to detect radio transmissions. They'd be everywhere, or at least their Von Neumann machines would be.

I mean, what's the super-advanced alien equivalent of this?
upload_2018-7-18_10-29-7.png
 
StewartR said:
What is the technological prowess of a civilisation which is, say, 1,000,000 years or 1,000,000,000 years more advanced than ours?
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I think one of the problems is that the assumption is made that longevity is proportional to advancement in civilization and technology.
Even if somewhere has life that makes the jump to complex multicellularism, it may just specialise to it's environment, which doesn't require what we're looking for.
Take dinosaurs; they appeared 250,000,000 years ago, and became the most widespread and successful lifeforms of their time. Their descendants, the birds are still with us, but there's no evidence they ever had a civilization, technology, or even language. The same is true for all terrestrial life except for us, so using that as a start point, habitable planets could be teaming with very mature lifeforms that have neither the desire nor ability to announce themselves to the universe.
 
Tori_T said:
I think one of the problems is that the assumption is made that longevity is proportional to advancement in civilization and technology.
Even if somewhere has life that makes the jump to complex multicellularism, it may just specialise to it's environment, which doesn't require what we're looking for.
Take dinosaurs; they appeared 250,000,000 years ago, and became the most widespread and successful lifeforms of their time. Their descendants, the birds are still with us, but there's no evidence they ever had a civilization, technology, or even language. The same is true for all terrestrial life except for us, so using that as a start point, habitable planets could be teaming with very mature lifeforms that have neither the desire nor ability to announce themselves to the universe.
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This

We assume life will develop to be advanced in technology and as @Tori_T points out the dinosaurs never did. If the meteor had never struck earth and wiped them out they probably still never would.
 
Bringing it a lot nearer to our time, what would the Romans have achieved if they could have developed mathematics? You cannot do maths with roman numerals so no trigonometry or logarithms so no engineering in the modern sense, if they had made that intuitive leap then the world would likely be a different place.

But we always assume alien life will be like us. Suppose intelligent life evolved from ants and used pheromones to communicate, there could be intelligent life out there now which is busily spraying pheromones into the galaxy and wondering why no one is sending pheromones back.
 
Raymond Lin said:
I mean it is possible that we are the only intelligent life out there.
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Given the history of this planet since 1914, let alone before that, I fail to see any proof that there is intelligent life on this one.
 
sirch said:
But we always assume alien life will be like us. Suppose intelligent life evolved from ants and used pheromones to communicate, there could be intelligent life out there now which is busily spraying pheromones into the galaxy and wondering why no one is sending pheromones back.
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It doesn't have to be organic life form at all. We could already envision a nightmare scenario where an advanced silicon based AI starts to self replicate colonising the Earth and beyond. It is just as likely to originate on other solar systems and we have no idea how it would evolve beyond that point, but you could be it will.

And that is before you even consider the invisible or spiritual realm. Does life form need to be made of "tangible" solid / liquid state matter at all?
 
LongLensPhotography said:
I And that is before you even consider the invisible or spiritual realm. Does life form need to be made of "tangible" solid / liquid state matter at all?
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There is school of thought that all matter is composed of electro-magnetic vibrations, light being one example, which are all vibrating at different frequencies, the lower the frequency the denser the material and vice versa.
 
Earley Man said:
There is school of thought that all matter is composed of electro-magnetic vibrations, light being one example, which are all vibrating at different frequencies, the lower the frequency the denser the material and vice versa.
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We know for a fact that matter we see and feel is composed of atoms, made up of protons, neutrons and electrons, before going deeper into the subatomic world. When you look into quantum mechanics it is evident that all these particles are actually electromagnetic waves, and you could solve very complex wave-function mathematical equations for all of them if you magically possessed enough computing power! Weird things are happening at sub 0K temperatures and even light has been demonstrated to slow down. Have you heard of quantum entanglement? It gets very steep further down the rabbit hole and we know that we still don't know about the remaining 95%, or maybe even 99.5%.
 
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