The Fermi Paradox

Perknose

Forum Director & Omnipotent Overlord
Forum Director
Oct 9, 1999
46,521
9,831
146
Paywall Scientific American article:

"The year is 1950. Physicist Enrico Fermi is eating lunch with a few colleagues outside Los Alamos National Laboratory in New Mexico. His shirt ripples in a hot desert wind.

He looks up at the sky and reportedly says, “Where is everybody?”


He is talking about space aliens. Known as the Fermi paradox, the question still hasn’t been answered. Despite numerous anecdotal reports, there is no convincing evidence of alien life or technology within our solar system (or, for that matter, in the cosmos at large).

The absence of evidence for aliens could be because they don’t exist or because our sampling depth is inadequate to detect them—a bit like declaring the entire ocean free of fish when none appear in a scooped-up bucket of seawater. Sampling depth refers to how thoroughly and keenly we can conduct a search. Fermi’s question is valuable because it narrows the possibilities down to two: either aliens are not present near Earth, or our current search methods are insufficient.

[...]

If interstellar expansion is plausible, we owe it to science to reconsider the dichotomy underpinning Fermi’s famous question. As strange as it sounds, we must revisit our sampling depth. What are the chances we could detect an interstellar spacecraft if it were present nearby? Have we overlooked anything?

[...]

From our privileged position in history, we know that advances in energy use often come with increases in efficiency, not simply increases in size or expansiveness. Think of the modern miniaturization of smartphones versus the mid-20th-century trend of computers that filled up whole rooms. Perhaps we should be looking for sophisticated and compact alien spacecraft, rather than motherships spewing misused energy.

With this in mind, we can imagine going back to 1950 and rephrasing Fermi’s famed lunchtime question.

His shirt ripples in a hot desert wind. He looks up at the sky.


“Where are all the loud, obvious indicators of aliens?” he asks.

When phrased like this, the simplest explanation stands out like a sore thumb. Perhaps aliens don’t leave loud, obvious indicators. Perhaps their vehicles are nearby, and perhaps no one has bothered to check properly—yet."

^^^ "The truth" is closer than we think?
 
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pmv

Lifer
May 30, 2008
13,570
8,469
136
Not in any way an original thought, but my vote is for the idea that technologically-advanced civilisations don't survive long enough to get to the point where they can travel beyond their own star system. They almost certainly destroy themselves through stupidity and/or just a general inability to get along among themselves long before getting to that point.

A corollary would be that any alien civilization that does appear will be something insect-like and hive-minded.
 

Muse

Lifer
Jul 11, 2001
38,308
8,624
136
Interstellar travel is technologically daunting. A guy I went to high school with and one-time best friend and subsequently highly successful astrophysicist and developer of essential modern space /earth communication technologies says that the human race is now in a position to develop interstellar human travel on a big scale.

He explains this in detail:

Steven Kilston

 

Stokely

Platinum Member
Jun 5, 2017
2,176
2,902
136
My cynical take is that we probably don't want to find aliens. Not because an advanced species that can travel here would want to "invade" (ludicrous), but because they might rightly see us as vermin that shouldn't ever be allowed to spread off-planet. Not until we actually evolve a bit. No actual decent galactic culture is going to want poo-flinging tribal apes in the mix. We seem to be going in the wrong direction seeing the spread of conspiracy garbage going more mainstream year by year....

And that's a theme from several book series I've read. One I really like is by Alastair Reynolds, where an ancient machine race left over from a massive war seeded the galaxy with weird artifacts. Any species that can evolve technologically to the point where they can travel to and open an artifact, it sets off a beacon. That lets the machine race know, hey time to bring out the extermination kit again, we have another nasty spreading virus to wipe out And that pretty much explains the now-empty galaxy.

There's a similar race in the Bob-o-verse, which is a really funny and good series starting with "I am Bob" that I highly recommend.
 
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Paratus

Lifer
Jun 4, 2004
17,069
14,338
146
So the show / book series the Expanse covered the Drake Equation and Fermi paradox.



To understand the science behind what the authors were going for we should talk about the Drake Equation, the Fermi Paradox, and the Great Filter.



The Drake Equation is a way to estimate the number of technological civilizations in the galaxy.



N = R* x Fp x Ne x Fl x Fi x Fc x L

N - number of detectable technological civilizations

R* - rate of star formation

Fp - fraction of stars systems with planets

Ne - avg number of planets per system that can support life

Fl - fraction of planets that develop life

Fi - fraction that develop intelligent life

Fc - fraction that develop a technological civilization

L - avg length of time the civilization is active



Depending on the assumptions for these variables and length of time the galaxy has existed there should be several alien civilizations that are detectable - there aren’t. Which brings us to the Fermi Paradox. Where is everyone? Even with conservative estimates for the variables there should be somebody detectable around.



Since there isn’t, that means something drives the estimates to be much lower than we think they are. That could be REALLY bad for humanity.



The hypothesis for why there is no other detectable alien civilizations around is called The Great Filter. It assumes there is one or multiple “filters” that affects the term(s) in the Drake equation.



For example if planets like Earth that could support life are extremely rare then intelligent aliens would also be extremely rare. If the conditions that allow life to form are extremely specific then maybe it rarely happens and again intelligent life would be very rare.



Now for some of these terms our technology helps us make a good estimate. Astronomy gives us a good idea of how many stars there are and how fast they are forming. Since the 90’s we’ve gotten better at finding planets around those stars including ones in similar orbits to Earth. In the next couple of decades we can probably narrow down how likely some of those are to have atmospheres like Earth.



The problem for humans is what if the filter is on the last term, the length of a technological civilization. If it turns out there are plenty of habitable planets and intelligent life easily occurs again again, yet we don’t detect them, then something prevents civilizations from existing for very long. Something like most civilizations tend to wipe themselves out via war or environmental collapse. Or maybe natural phenomena like supernovas and gamma ray bursts happen frequently enough to sterilize almost all planets with life on them.



Or maybe some advanced race of aliens sends some mysterious blue goo to your solar system that could have wiped out all life on Earth if it hadn’t gotten caught by Saturn. Young species making loud “noises” in the galaxy and then being prayed upon by more advanced species is a filter called the Dark Forest hypothesis. It’s from the 3 Body book series. You either stay quiet and hunt or become the hunted.



At any rate lets hope we are passed the filter since our civilization is detectable in greater than 100 light year diameter sphere via our radio transmissions. Which suggests we might not have
 
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Muse

Lifer
Jul 11, 2001
38,308
8,624
136
As advocated in Steven Kilston's video linked above, book to read on this is:

Rare Earth: Why Complex Life is Uncommon in the Universe

From Wikipedia, the free encyclopedia

Rare Earth: Why Complex Life Is Uncommon in the Universe
AuthorsPeter D. Ward
Donald E. Brownlee
LanguageEnglish
SubjectAstrobiology
PublisherCopernicus
Publication date2000
Publication placeUnited States
Media typePrint
Pages338 pp.
ISBN978-0387952895
Rare Earth: Why Complex Life Is Uncommon in the Universe is a 2000 popular science book about xenobiology by Peter Ward, a geologist and evolutionary biologist, and Donald E. Brownlee, a cosmologist and astrobiologist. The book is the origin of the term 'Rare Earth Hypothesis' which denotes the central claim of the book: that complex life is rare in the universe.
 

hal2kilo

Lifer
Feb 24, 2009
24,137
10,823
136
My cynical take is that we probably don't want to find aliens. Not because an advanced species that can travel here would want to "invade" (ludicrous), but because they might rightly see us as vermin that shouldn't ever be allowed to spread off-planet. Not until we actually evolve a bit. No actual decent galactic culture is going to want poo-flinging tribal apes in the mix. We seem to be going in the wrong direction seeing the spread of conspiracy garbage going more mainstream year by year....

And that's a theme from several book series I've read. One I really like is by Alastair Reynolds, where an ancient machine race left over from a massive war seeded the galaxy with weird artifacts. Any species that can evolve technologically to the point where they can travel to and open an artifact, it sets off a beacon. That lets the machine race know, hey time to bring out the extermination kit again, we have another nasty spreading virus to wipe out And that pretty much explains the now-empty galaxy.

There's a similar race in the Bob-o-verse, which is a really funny and good series starting with "I am Bob" that I highly recommend.
Sounds very Alien/Prometheus like.
As to the original op, have you not with the advent of millions of cell phone cameras seen that there is all kinds of evidence of tech out there that we, as in the earth human we, have no idea what is going on. Evidence of portals and wormholes naturally occurring on this earth are being investigated as we speak.
We only perceive 3 to 4 dimensions, which may make us blind to many other things.
 
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BoomerD

No Lifer
Feb 26, 2006
64,023
12,348
136
Maybe, just maybe…any alien civilization who has gotten close enough to notice us…has some kind of Prime Directive that prevents them from making contact with backwards civilizations like ours. It’s for damed sure, if they’ve been around long enough to watch our “progress,” they’ll stay far away.
 

cytg111

Lifer
Mar 17, 2008
23,931
13,426
136
All this is dependent on light being the speed barrier.

Really? Thats a staggering failure of the imagination.
 
Reactions: hal2kilo

MtnMan

Diamond Member
Jul 27, 2004
8,927
8,132
136
The absence of extraterrestrial intelligence visiting earth is clearly demonstrated by the fact they only visit trailer parks. Maybe there are extraterrestrial aliens, but based on that, intelligence is not their strong suite.
 

trenchfoot

Lifer
Aug 5, 2000
14,859
7,391
136
As a teenager I was given the opportunity to work part-time at our local Planetarium. The curator and manager of it was a guy named George Bunton. I was hired to create illustrations for a revision of a book about the constellations (my art teacher colluded with my architecture teacher to get me in). At that young age George gave me an in-depth look into the Cosmos, treating me to night time viewings of the objects in space through the Planetariums (what seemed to me at the time) huge telescope. What I came away with through the sharing of his knowledge along with the research I had to do to correctly illustrate his vision of the constellations was a very deep appreciation of what's out there that we can see and hear and what could possibly be beyond our primitive means of understanding our place in the known universe.

I recall how he said he was envious of me in the sense that he could see how emerging technologies would continue to unravel the mysteries of our existence, our purpose and place in the big picture of things and that if he could only be around for another 50 years (this was in the early sixties and so was he) he could have enjoyed the inevitable leaps and bounds of progress that was already occurring in that filed of science. In a nutshell, from what I learned about how the universe works through George, it's pretty much a given that there are other sentient forms of life somewhere out there in the vastness.
 
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Zorba

Lifer
Oct 22, 1999
15,182
10,735
136
So the show / book series the Expanse covered the Drake Equation and Fermi paradox.



To understand the science behind what the authors were going for we should talk about the Drake Equation, the Fermi Paradox, and the Great Filter.



The Drake Equation is a way to estimate the number of technological civilizations in the galaxy.



N = R* x Fp x Ne x Fl x Fi x Fc x L

N - number of detectable technological civilizations

R* - rate of star formation

Fp - fraction of stars systems with planets

Ne - avg number of planets per system that can support life

Fl - fraction of planets that develop life

Fi - fraction that develop intelligent life

Fc - fraction that develop a technological civilization

L - avg length of time the civilization is active



Depending on the assumptions for these variables and length of time the galaxy has existed there should be several alien civilizations that are detectable - there aren’t. Which brings us to the Fermi Paradox. Where is everyone? Even with conservative estimates for the variables there should be somebody detectable around.



Since there isn’t, that means something drives the estimates to be much lower than we think they are. That could be REALLY bad for humanity.



The hypothesis for why there is no other detectable alien civilizations around is called The Great Filter. It assumes there is one or multiple “filters” that affects the term(s) in the Drake equation.



For example if planets like Earth that could support life are extremely rare then intelligent aliens would also be extremely rare. If the conditions that allow life to form are extremely specific then maybe it rarely happens and again intelligent life would be very rare.



Now for some of these terms our technology helps us make a good estimate. Astronomy gives us a good idea of how many stars there are and how fast they are forming. Since the 90’s we’ve gotten better at finding planets around those stars including ones in similar orbits to Earth. In the next couple of decades we can probably narrow down how likely some of those are to have atmospheres like Earth.



The problem for humans is what if the filter is on the last term, the length of a technological civilization. If it turns out there are plenty of habitable planets and intelligent life easily occurs again again, yet we don’t detect them, then something prevents civilizations from existing for very long. Something like most civilizations tend to wipe themselves out via war or environmental collapse. Or maybe natural phenomena like supernovas and gamma ray bursts happen frequently enough to sterilize almost all planets with life on them.



Or maybe some advanced race of aliens sends some mysterious blue goo to your solar system that could have wiped out all life on Earth if it hadn’t gotten caught by Saturn. Young species making loud “noises” in the galaxy and then being prayed upon by more advanced species is a filter called the Dark Forest hypothesis. It’s from the 3 Body book series. You either stay quiet and hunt or become the hunted.



At any rate lets hope we are passed the filter since our civilization is detectable in greater than 100 light year diameter sphere via our radio transmissions. Which suggests we might not have
There was a good podcast series on this many years ago, called "The End of the World." https://www.iheart.com/podcast/105-the-end-of-the-world-with-30006093/

Don't worry, a lab leaked super virus was one of the possible filters, 2 years before COVID.
 

gorobei

Diamond Member
Jan 7, 2007
3,768
1,208
136
analog radio/tv was just pumping tons of watts to deal with the range limitations.
wired cable tv, internet, local wifi means you dont need to use as many watts because you have an infrastructure of repeaters or local connections.
analog to digital to encrypted digital for security means the signals become indistinguishable from static.

all of these things happened in roughly 100 years. the window of a civilization blasting out detectable analog radio waves into the wide open is potentially tiny.
 
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gothuevos

Platinum Member
Jul 28, 2010
2,279
1,825
136
Maybe, just maybe…any alien civilization who has gotten close enough to notice us…has some kind of Prime Directive that prevents them from making contact with backwards civilizations like ours. It’s for damed sure, if they’ve been around long enough to watch our “progress,” they’ll stay far away.

They're just waiting until they see us develop our first warp drive.
 

Jaskalas

Lifer
Jun 23, 2004
33,894
7,916
136
Nothing I have seen, or read in our history, tells me that we would be worthy.
If we ever live long enough to build something that can go FTL, then maybe we can join the big boys.
Until then, it is hubris to think we're any better than another animal.

For now, let's see if we can keep and maintain something so basic as enlightenment and the scientific method.
The way we reacted to the internet has put everything above caveman at risk.
If we cannot stabilize our societies, there won't be anything for aliens to find.
 

woolfe9998

Lifer
Apr 8, 2013
16,189
14,114
136
The conditions necessary to produce and sustain complex life, particularly thriving biodiverse ecosystems necessary to even have a chance of producing a sentient species, are extremely narrow and unlikely. The earth is this way due to fantastic luck on a cosmic scale.

We first had an impact with a Mars sized planet early on, which worked out very well for Earth. Most of it's mass combined with Earth while both planets went molten again, and hence the new iron enlarged Earth's existing iron core, which in turn gave us a strong magnetic field that will last about 7 billion years instead of like 1 billion which is all the other rocky planets got. The field protects us from solar flares, CME's, cosmic rays and most importantly, solar winds, which would have blown away all our atmosphere and with it all our oceans. Like what happened on Mars.

No other planet or moon in our solar system, other than a gas or ice giant, has a significant magnetic field. Meaning it is a rare exception.

Second, the throw-off from the impact orbited the Earth for millions of years until it formed the moon. This weirdly over-size moon, in turn, stabilizes our axial wobble, preventing constant violent climate change. And second, it gives us gravitational tidal force which churns our oceans, which we likely could not have had abiogenesis without.

Then there's our vast abundance of water. We don't even know how we got this much as it seems comet impacts wouldn't have been enough. But this much water is unusual, including among exo-planets we've observed.

This is not even to speak of our "goldilocks" orbital position, or our lack of world killing features like Venus' over-active volcanism.

When we look at exo-planets so far, we see very few small rocky worlds. We see lots of super-earths. They now think this is the normal development of a solar system, to form lots of super-earths out of its inner rocky material. But they think something weird happened here, like Jupiter inched in a little closer to Mars, and gravitationally pulled the super-earths from behind, causing them to lose orbital speed and spiral into the sun. The smaller amount of rocks left over formed the four small rocky planets which are the only kind that can sustain complex life. But only do under extremely rare conditions.

The point of all that detail is that it's really unlikely to have a planet with conditions near enough to earth to sustain thriving diverse ecosystems. Might be like 1 in a million to 1 in a billion planets. Though we may have about a trillion planets in the galaxy.

So I doubt there's many others out there. We might be the only ones in the galaxy, or perhaps there are 2 or 3 co-existing at a given time. But unless one of us really develops "subspace communications" and/or "warp drive" we'll never meet them or talk to them.
 

Racan

Golden Member
Sep 22, 2012
1,140
2,071
136
All this is dependent on light being the speed barrier.

Really? Thats a staggering failure of the imagination.
If FTL is possible then the lack of evidence for intelligent alien life so far is even more baffling.
 

Shmee

Memory & Storage, Graphics Cards Mod Elite Member
Super Moderator
Sep 13, 2008
7,673
2,654
146
At first I thought this thread was going to be about Nvidia's power hungry DX11 GPU architecture. Still, this thread is cool.
 
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cytg111

Lifer
Mar 17, 2008
23,931
13,426
136
If FTL is possible then the lack of evidence for intelligent alien life so far is even more baffling.

I think that is ill conceived conjecture. Are you intruding on every single anthill in existence?
 

Racan

Golden Member
Sep 22, 2012
1,140
2,071
136
I think that is ill conceived conjecture. Are you intruding on every single anthill in existence?
I mean from what we've observed so far with our instruments probing the EM spectrum in our Galaxy and other galaxies we haven't observed things that can't be explained naturally. Dyson spheres and the like.

May be we will find something as more advanced telescopes are coming online but I'm not holding my breath.
 
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