Researchers Say The Aliens Are Silent Because They Are Extinct (theconversation.com) 559
HughPickens.com writes: The Conversation reports that according to research by Dr. Charles Lineweaver and Dr. Aditya Chopra, a plausible solution to Fermi's paradox is near universal early extinction of life on exoplanets, which they have named the Gaian Bottleneck. "The universe is probably filled with habitable planets, so many scientists think it should be teeming with aliens," says Chopra. "The mystery of why we haven't yet found signs of aliens may have less to do with the likelihood of the origin of life or intelligence and have more to do with the rarity of the rapid emergence of biological regulation of feedback cycles on planetary surfaces." According to the researchers, most early planetary environments are unstable. To produce a habitable planet, life forms need to regulate greenhouse gases such as water and carbon dioxide to keep surface temperatures stable. About four billion years ago, Earth, Venus and Mars may have all been habitable. However, a billion years or so after formation, Venus turned into a hothouse and Mars froze into an icebox. Even if wet rocky Earth-like planets are in the "Goldilocks Zone" of their host stars, it seems that runaway freezing or heating may be their default fate. Large impactors and huge variation in the amounts of water and greenhouse gases can also induce positive feedback cycles that push planets away from habitable conditions. The difference on Earth may be that as soon as life became widespread on our planet, the earliest metabolisms began to modulate the greenhouse gas composition of the atmosphere. "The emergence of life's ability to regulate initially non-biological feedback mechanisms could be the most significant factor responsible for life's persistence on Earth, conclude Lineweaver and Chopra. "Even if life does emerge on a planet, it rarely evolves quickly enough to regulate greenhouse gases, and thereby keep surface temperatures compatible with liquid water and habitability."
It's a f... (Score:4, Funny)
Re:It's a f... (Score:5, Interesting)
Except that it ignores subsurface oceans, which seem to be quite stable over long timeperiods and quite likely to be very abundant in the universe.
Sure, a species evolved to an undersea environment faces challenges in getting to their surface and beyond... but if we can get out of this deep gravity well after such a (geologically) short period of time after our species' evolution, sentient species in subsurface oceans with hundreds of millions or billion years on their "hands" would surely deal with the technical difficulties.
And of course there's also the possibility of LNAWKI, but let's just stick with LAWKI for now.
My personal suspicion is that a wide variety of factors work together to keep complex life rather rare on a per-planet basis, great distances dilute any signals from any that do achieve sentience, and the speed of light and difficulty of propagating a civilization outward at near that limit keeps the vast majority far away. Basically, rarity + dilution. But that's just my suspicion.
Re:It's a f... (Score:5, Interesting)
My personal theory is that the most likely thing for any intelligent and technologically capable alien race to be doing is exactly what *we* are doing. Listen, and with a small budget - so only listening to a very small part of the spectrum from a tiny part of the sky. That golden record on voyager 1 is about the last major attempt we made at sending anything and it wasn't a very sensible one.
But if that was what economics led to here, why would we assume it would have other outcomes elsewhere ? Literally the only experimental sample of a technologically capable space-faring race we have - did this one.
So it's perfectly likely that there dozens of alien races within easy communications range of us all making a half-hearted attempt at listening and waiting for one of the others to talk first. All of them, in fact, hoping the outsource the expense of sending high-powered signals into a void where you don't know if anybody is listening, don't know if anybody who was listening would be able to understand it and don't even know in which direction to aim - to one of the others.
Exactly because sending messages is so incredibly difficult technically, and expensive, they may all have opted to just listen instead and, like us, hope that one of the others will figure out transmission first so they can justify the budget to build a transmitter to reply with.
Re:It's a f... (Score:4, Interesting)
> My personal theory is that the most likely thing for any intelligent and technologically capable alien race to be doing is exactly what *we* are doing.
Exactly - making ourselves go extinct over the cosmological blip of a few hundred years, by systematically undermining our own life conditions (us: global warming); by squandering non-replenishable resources (oil, gas, rare earth elements); by maintaining nation states that act like we don't share a planet (Putin's Russia, North Korea, China, Arab / Islam countries, USA etc.); by creating weapons that allow more and more destructive potential per user (nuclear, biological and autonomous weapons); and by resisting the completion of the surveillance police state and precrime, which are pretty much the only means to ensure that terrorists are killed before they can fake some nuclear attack, setting off WWIII, or release some plague that wipes out half of mankind and destroys economy as we know it.
Once we global-warm, war or terrorism ourselves back into a pre-technological tribe, we'll no longer have the chance for an industrial and thus technological revolution, for we have already used up most of the easily accessible oil and gas; no more radio telescopes sent to space.
Maybe we can't observe other intelligent life simply because chances are, any transmission is puny and fleeting on the cosmological scale, making reception incredibly unlikely. However maybe there are intelligent creatures that enjoyed their brief technological triumph, only to be followed by millions of years of an eternal Stone Age in the optimistic doom scenario when large bodied intelligent creatures can even survive their own technological windfall.
The rare few civilizations that survive the high mortality rate of technological infancy might evolve to such superpowers that they have unimaginable matter manipulation and computational capabilities in their hand. We, at such premature stage, already build vast, large simulations even without really trying (called games or machine learning environments). They (and maybe we) then go on building new universes which themselves beget alife, some of which may become powerful to build their own simulations. Then, we can conclude that believing that we are World #1 is the same anthropocentric view and hubris as geocentrism was a moment ago. Most probably we're currently on the bottom of a deep stack, hoping for adequate power redundancy and backup procedures in all layers above.
In conclusion, most of the fellow technological civilizations are behind us or ahead of us (time), or above us and maybe at some point, below us (simulation stack). All except the last of these are very unlikely to encounter and detect.
Re:It's a f... (Score:4, Informative)
Well, except for the fact that most such signals would originate from very close to massive radio-noise transmitters (aka stars), and it's estimated that our listening technology probably wouldn't be able to detect a perfect twin of our civilization through the noise from more than a few light-years away. So there's *maybe* a small handful of the closest stars where we *might* be able to detect "ambient" signals from. Further than that, and they would have to be transmitting far more powerfully than we do.
The one exception is high-power military radar, which is often orders of magnitude stronger, and would be correspondingly easier to detect, but wouldn't necessarily appear to be an intelligent signal.
Also, while you're quite right about the time coordinating issue, you need to dial down your numbers a bit. From 10 billion light-years away an entire galaxy appears as barely a tiny smudge, if that, using our most sensitive detectors. Unless they were somehow blinking most of the stars in their galaxy in unison (as observed from Earth, which would require a very directional signal synchronized across tens of thousands of years), we wouldn't pick up even a hint of a signal.
Sadly, for now our technology is pretty much limited to listening for civilizations from relatively close within our own galaxy intentionally trying to contact us.
On the bright side we've been sending a pretty strong signal that our planet harbors life, or at least is something pretty unusual, for many millions of years. Just as we're beginning spectrographically analyze the atmospheres of exoplanets that pass between us and their sun, aliens residing close to Earth's orbital plane can do the same - and given the volatility of free oxygen, the concentrations of it in our atmosphere should make it clear that something very unusual is happening here.
Comment removed (Score:5, Funny)
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Re:It's a f... (Score:5, Insightful)
All speculation about alien life tends to founder on the issue of small sample size, but already we observe that our machines 'like' space and extraterrestrial surface environments much better than our squishy carbon-based bodies do. So perhaps the leading candidate for LNAWKI would be something like our silicon-based emissaries. If the same process has been going on elsewhere we may find that (a) the most likely aliens we encounter will be machines, and (b) the encounter will be by our own machines.
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LNAWKI what is that supposed to mean? /. posts.
The only "useful" cough cough google results are two
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LAWKI = Life As We Know It
LNAWKI = Life Not As We Know It
There are lots of variants of the latter, while the former is pretty standardized.
Re:It's a f... (Score:5, Informative)
Unfortunately, these geek acronyms tend to be English-specific. Some others you will encounter here:
RTKBA - Right to keep and bear arms;
TEOTWAWKI - The end of the world as we know it;
DYKWIA - "Do you know who I am?"
SJW - Social justice warrior
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Sure, a species evolved to an undersea environment faces challenges in getting to their surface and beyond...
It would be much easier for a sentient undersea creature like an octopus to colonize the surface of their own planet than it would be for us to colonize the moon. As an added advantage, once a creature like the octopus has colonized the surface of their planet, they would already have most of the required technology to colonize other worlds. They would already have space suits, self-contained habitats, etc... The biggest problem I see (with an obvious LAWKI bias) is that most of our technology is electri
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On the other hand, some things can be easier underwater - for example, moving heavy objects (with buoyancy), long distance communication, etc. And of course the main drivers for advancement still exist, things like farming, hunting, armaments, defense, etc.
Electricity still works underwater (though AC not as well, and of course insulation is important). The same basic lines of progression work underwater. You can still make a "potato battery" type cell underwater with native copper, you can move lodeston
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Except that it ignores subsurface oceans, which seem to be quite stable over long timeperiods and quite likely to be very abundant in the universe.
Agreed - and since it seems life on earth began in the oceans, it's a very likely proposition.
Sure, a species evolved to an undersea environment faces challenges in getting to their surface and beyond... but if we can get out of this deep gravity well after such a (geologically) short period of time after our species' evolution, sentient species in subsurface oceans with hundreds of millions or billion years on their "hands" would surely deal with the technical difficulties.
This I disagree with. An intelligent ocean-based life form is going to have to find a way to work with steel to get to space, and that can't be done below the surface in any way I've ever been able to imagine.
Without the ability to smelt iron / steel, etc. they just aren't going to be able to migrate on to land, never mind into the atmosphere, never mind space.
I'd be interested in any ideas you have on how they mi
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Apart from the illogic of an advance long lived species desire to remain bound to an unstable planetary surface, with variable stellar output and not being able to get out of the way of undeflectably large impacts. The greater stability of mobile orbital colonies and say city ships makes it logical, that while more primitive planetary bound elements of the society went extinct, the more advanced elements simply continued within more replaceable enduring environments. Not to mention the very strange idea, t
Its... (Score:3)
The mystery of why we haven't yet found signs of aliens may have less to do with the likelihood of the origin of life or intelligence and have more to do with the rarity of the rapid emergence of biological regulation of feedback cycles on planetary surface
Monty Python
.. I mean It's the distance .. the distance
err
Re:Its... (Score:5, Insightful)
Yep, it's the distance.
And whatever constitutes "teeming with aliens". Is that 10 planets per galaxy? 100? 1,000?
And the time involved. How long ago did life start on Earth? How many mass extinctions have there been? Would ANY of those have been detected by aliens on their home planet using technology equivalent to ours?
The Fermi "paradox" is based upon alien expansion. Which is, in turn, based upon tech advances that we don't have.
The galaxy could be "teeming with aliens" that we cannot detect and that we cannot reach with our technology. Nor can they detect us or reach us.
The Fermi "paradox" is bullshit (Score:5, Insightful)
For four billion years, life on Earth was microscopic blobs of goo.
Then 600 million years ago - BAM - complex life emerged pretty much in the blink of an eye.
We have no idea how likely that transition to complex life 600 million years ago was - we have a sample size of ONE.
Now go back an read my first sentence: For four billion years, life on Earth was microscopic blobs of goo.
That four billion years was about half the expected lifetime of the Earth. The probability that complex life evolves may very well be infinitesimally small. WE DON'T KNOW.
Believing the universe must be teeming with intelligence is based on nothing more than faith.
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For four billion years, life on Earth was microscopic blobs of goo.
Then 600 million years ago - BAM - complex life emerged pretty much in the blink of an eye.
We have no idea how likely that transition to complex life 600 million years ago was - we have a sample size of ONE.
Now go back an read my first sentence: For four billion years, life on Earth was microscopic blobs of goo.
That four billion years was about half the expected lifetime of the Earth. The probability that complex life evolves may very well be infinitesimally small. WE DON'T KNOW.
Believing the universe must be teeming with intelligence is based on nothing more than faith.
Actually, the odds are worse than that. Mass extinctions have happened with monotonous regularity in the history of the world, and only comparatively recently have life forms evolved with internal skeletons that enabled them to get to be quite big. Insects and arthropods probably don't get big enough to carry large enough brains to become intelligent, but arthropods seem to evolve a lot more easily than do vertebrates.
Even when you look at vertebrates, a tendency to evolve big brains seems to be exclusively
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You seem to be ignoring absolute brain size here. Especially since small dinosaurs (you know, like parrots) have a brain:body mass ratio considerably larger than humans do (1:12 for small birds, 1:40 for humans).
In any case, brain to body mass ratio is just part of the answer, not a complete picture of the issue of intelligence.
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Yep, it's the distance.
And whatever constitutes "teeming with aliens". Is that 10 planets per galaxy? 100? 1,000?
And the time involved. How long ago did life start on Earth? How many mass extinctions have there been? Would ANY of those have been detected by aliens on their home planet using technology equivalent to ours?
The Fermi "paradox" is based upon alien expansion. Which is, in turn, based upon tech advances that we don't have.
The galaxy could be "teeming with aliens" that we cannot detect and that we cannot reach with our technology. Nor can they detect us or reach us.
To be fair, if we never hard the dark ages and big stretches of time that religion was in charge and very little actual progress was made we would probably be way ahead of where we are now.
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They might even be communicating with each other but using a communications method that we can't detect. Imagine if you had a medieval civilization on a planet and an advanced civilization blasted radio waves all over to communicate. The medieval folks wouldn't have the technology to intercept and interpret the radio waves so the advanced civilization would be invisible to them.
Re:Its... (Score:5, Informative)
One thing to bear in mind is that life here existed in the form of anaerobic bacteria for a staggeringly long time. Photosynthesis began as a way to split hydrogen sulphide into useful hydrogen ions and a useless waste product of elemental sulphur, which was also usefully inert. Early photosynthesis therefore didn't require much in the way of biochemical sophistication to operate; the waste sulphur is where some large sulphur deposits originated.
That changed with a mutation which let the photosynthesis split not hydrogen sulphide, but water into useful hydrogen and (to anaerobic bacteria) highly toxic and dangerous oxygen. That initially wasn't all that big a problem to early water-splitters; the oceans they were in were rich in iron-II salts which readily absorbed oxygen to become insoluble iron-III salts (this is where the banded iron rock formations come from).
Everything changed when most of the iron-II in solution in the early earth's oceans was used up. Oxygen levels slowly rose, and virtually all bacterial species either adapted or went extinct. Oxygen is toxic to most bacteria.
I would hypothesise that most alien worlds either never make the switch from anaerobic atmosphere to aerobic one, or fail to establish a homeostatic oxygen-nitrogen atmosphere quickly enough and effectively enough to become self-regulating.
Re:Its... (Score:5, Funny)
We don't even have the Concorde anymore, or the SR-71, in some ways we've gone backwards.
The only way in which the Concorde and SR-71 were not primitive is that they were fast. But the mindset of burning up that much fuel so that Rod Stewart can get a haircut in another country and still wind up looking like an aged lesbian or so that we can spy on another country so that we can more effectively wage a cold war against them is seriously fucking backwards.
Getting rid of the Concorde and the SR-71 might seem technologically backwards, but in fact, it is a huge step in the correct direction. Do you seriously suggest that advanced aliens would be flying around at supersonic speeds for no good reason? How inefficient.
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Do you seriously suggest that advanced aliens would be flying around at supersonic speeds for no good reason? How inefficient.
Supersonic in interstellar/interplanetary terms would be like going cross country on a push bike
Re:Its... (Score:5, Funny)
Supersonic in interstellar/interplanetary terms would be like going cross country on a push bike
In space, no one can hear you trying to exceed the speed of sound.
Re:Its... (Score:4, Informative)
In space, a snail can exceed the speed of sound.
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What we see is *it* as far as technology goes. We might get a few more generations of CPUs, but we'll still see the same airplanes, rockets, and cars as pretty much 50 years ago. We don't even have the Concorde anymore, or the SR-71, in some ways we've gone backwards.
Welp, might as well shut down all R we've invented and discovered everything! It didn't take too long, did it?
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What about the em-drive? That is new physics and would even be applicable to space travel.
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"We don't even have the Concorde anymore, or the SR-71, in some ways we've gone backwards."
But fortunately, there is intelligent life in Asia.
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To get a technological head start and a head start out in space an alien species would been part of an evolutionary process that skipped whatever their equivalent of dinosaurs would have been and gone directly to intelligent life capable of technology.
Say what ?
We're probably talking about a timeframe measured in tens of thousands of years at most. On planetary timescales even a eye blink analogy is woefully inadequate.
That said, I'm personally of the belief that most intelligent/technologically advanced s
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Re:Its... (Score:4, Interesting)
I think you're missing the point.
An alien civilisation with a mere few hundred years head start on humanity would probably have technology that was nearly magical to us if we were to meet them today.
Stretch that out to a few tens of thousands of years - still utterly irrelevant on a timescale measured in billions of years - and you've easily got the kind of civilisation the OP was talking about. Undetectable by us and completely uninterested in us.
From memory, even with the technology we have today we could colonise the entire galaxy in a million years. Not that I think any civilisation could remain stable for that long, but consider it in the context of the mere hundreds or thousands of years "head start" required as discussed earlier.
Re:Its... (Score:4, Interesting)
even with the technology we have today we could colonise the entire galaxy in a million years
No we could not. The milkyway has a diameter of about 100,000 light years, give or take.
To fly every where you would need at least 0.1c and may not be to far at the edge, which unfortunately is the case for the solar system.
With our technology we have no means to accelerate and decelerate a space ship with life on it to 0.1c.
You probably could "seed" the whole galaxy in 10 - 100 million years, but not in 1 million.
And bottom line: why would anyone really want to do that? Except for the curiousity like "wow lets dive as deep as we can and look what is there" there never will be a big appeal to space for most of the humans.
Would i like to go out visit the next star system? Yes, absolutely.
Would I like to go out to the next star system on a journey that will take so long that I definitely die on the way before we reach the destination? Absolutely not. There are much more fun activities I can do here on earth than on a what ever luxuries it might have, space ship.
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You're missing the point. Let's assume there's some necessary planetary time for complex life to evolve. To be very generous toward your argument, let's start the clock with the Cambrian explosion. Which was 500 million years ago. According to our understanding, intelligent life could have evolved earlier or later than how it happened on our planet. The GP mentions dinosaurs. Maybe they'd have evolved into a civilization, had they not been swept by some cataclism (or their own self-destroying technological
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All true, but look at our history of what we haughtily call civilization. It's a mere 10,000 years. And of those, we've made more technological progress in the last 200 years than the 9800 years before.
And now imagine they're off by "only" 1000 years, which is pretty much nothing on a time scale that deals with cosmological events.
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Re:Its... (Score:4, Interesting)
>To get a technological head start and a head start out in space an alien species would been part of an evolutionary process that skipped whatever their equivalent of dinosaurs would have been and gone directly to intelligent life capable of technology.
Firstly - why not ? We have no proof that there were NOT technologically advanced dinosaurs, at best we have strong reason to doubt there were spacefaring dinosaurs. You are underestimating just how massive an amount of deep time 65-million years was. Dinosaurs could have built cities five times bigger than New York and not a shred would have survived for us to find. If we go extinct tomorrow, it's unlikely that in 10-million years there will be any evidence whatsoever that we existed - except maybe a few primate fossils, even our best mummies can't make it that far. A hundred million ? Not a chance, by that point even our satelites would have decayed and crashed. The last evidence of our existence that may be around would be the bits of junk Apollo left on the moon and any future paleontologists (whether evolved here or elsewhere) that found that evidence would mostly wonder what the hell a Richard M. Nixon was... think about it, they would not even be sure whether it was left there by an earth-born species that reached the moon - or a long-lost lunar species that had a great council to end a war at that spot.
Secondly - your argument is flawed because that's not how time works, time is relative and doesn't happen at a constant rate. Planets that rotate their stars slower have physically existed longer than ones that move slower. So two planets around the same star, in different orbits, which orbit in the same timeframe, that formed together at the same time - the outer one will be significantly younger because time slows down as you speed up. It may be a matter of seconds per rotation - but there's been many billions of rotations for those to add up. And planets around more massive stars are regardless of when they formed relative to the big-bang, have had less time pass on them than those around smaller stars - because time slows down near bigger gravity wells.
The amount of "time" that passed on the surface of a planet is only very vaguely connected to the age of the universe and even to the age of that planet (which we measure relative to the age of the universe). The one decidedly does not offer any indications of the other. The only reason they happen to be the same on earth is because we happen to measure "years" by the time it takes our planet to rotate, but Jupiter formed at the same time as Earth did - and quite a lot less time has passed on Jupiter than on Earth. Even less have passed on the sun.
This is, actually, one reason why - if there is life on Io or Europa - that life is likely to be "bacterial" rather than fishes - those moons circle a massive planet, any life there has had significantly less time to evolve than life on earth has had. No, I don't feel like doing the math to figure out how much.
Re:Its... (Score:4, Informative)
You are underestimating just how massive an amount of deep time 65-million years was.
What would a radioactive waste storage look like in a 100M years? Ridiculously stable. Dry. Sealed from elements. Even if it literally just disintegrated in place, the odd mix and ratios of remaining isotopes at the site, surrounded by solid geologically stable rock millions of years older... would clearly suggest something unnatural.
Or perhaps a lego mini-fig -- tey'll soon outnumber humans after all.
http://xkcd.com/1281/ [xkcd.com]
Surely bunches of those highly stable bits of plastic will find themselves some place safe to hide... preserved in amber, or tarpits, or trapped in some glacier, at the bottom of the ocean, or in a salt mine... there are billions of them, so probably all of those things will happen.
And we have things like modern jewelry. Laser engraved diamonds, set in platinum bands. Stored inside fire proof safes... some which would end up buried in stable places... even bunkers. What's 65 million years going to do to that?
Secondly - your argument is flawed because that's not how time works, time is relative and doesn't happen at a constant rate. Planets that rotate their stars slower have physically existed longer than ones that move slower. So two planets around the same star, in different orbits, which orbit in the same timeframe, that formed together at the same time - the outer one will be significantly younger because time slows down as you speed up. It may be a matter of seconds per rotation - but there's been many billions of rotations for those to add up.
Ok... so lets put some figures into those numbers ... say 11 seconds for "a matter of seconds". And how about 4.6 billion for for "many billions" as that's the age of our solar system measured from earth's perspective at least.
11 seconds x 4.6 billion rotations = 1603 years. I don't think we need to worry too much about relative ages of the planets.
This is, actually, one reason why - if there is life on Io or Europa - that life is likely to be "bacterial" rather than fishes - those moons circle a massive planet, any life there has had significantly less time to evolve than life on earth has had. No, I don't feel like doing the math to figure out how much.
You really think its going to be billions of years though? I'm pretty skeptical. Maybe you should do the math.
Re:Its... (Score:5, Funny)
Monty Python
Maybe the aliens aren't quite dead yet . . . they are merely resting?
Tired and shagged out after a long squawk . . . ?
Or it's intern-planetary censorship . . . their governments are blocking them from contacting us . . . ?
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Could they define first what a life is? (Score:2)
Or (Score:2)
Or extinct because their suns have died. Either or.
Rarely Evolves?? (Score:2, Insightful)
"Even if life does emerge on a planet, it rarely evolves quickly enough to regulate greenhouse gases......"
Rarely? What is the sample size for the statistics?
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Re:Rarely Evolves?? (Score:4, Insightful)
It's the phrasing used. "[life] rarely evolves quickly enough to regulate greenhouse gases" implies that the origin of life on exoplanets been observed often enough for us to to determine that the probability of it evolving to regulate greenhouse gasses is low. We can't even prove how life began on earth, so we sure as hell can't determine the probability for it occurring and evolving on a planet light years away from us.
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This has been predicted in 1923! (Score:2)
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You forgot the Soviet Russia, no?
where meme forgets you?
Bill Watterson said it best (Score:5, Funny)
'Sometimes I think the surest sign that intelligent life exists elsewhere in the universe is that none of it has tried to contact us.'
So (Score:3)
Coupled with the odds of being alive and intelligent at the right time ...) long enough.
and putting in the resources to make one noticeable (large laser irradiating the sun, dyson sphere,
I'm not really that surprised there is yet another plausible factor that makes it hard.
The reason is... (Score:5, Interesting)
A good theory I read about somewhere is that the reason we can not find evidence is simply to do with technology either other alien cultures at the point in time we are witnessing there systems have not developed the technology that we can detect or they have moved beyond the need to blast everything in the entire em spectrum out to space.
How many years have we been detectable by other races and how many years left until our technology gets efficient enough that any trace of our race gets hidden by been simply cleaner with our em pollution.
Will we cease to exist to other races out there when we become undetectable?
Re:The reason is... (Score:5, Interesting)
As for the Fermi issue, IMHO radio signals just degrade too quickly across the vast distances for us to pick up currently (if ever). Even if the theoretical Alcubierre warp drive actually works, it's still only 10x the speed of light. In Star Trek terms, that's just a little over warp 2. Fermi was talking about a time period of millions of years though.
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So... Earth is like a huge intergalactic crapper?
Universe teeming with O'Neil Colonies (Score:5, Interesting)
They can be built around any reasonably stable star (especially very long-lived red dwarfs) which has some rubble to rebuild into spacious habitations. No need to seek a proper star or habitable/terraformable planet. No need to genetically warp ourselves or live in underground tunnels like morlocks. The Colonies provide the perfect living conditions for the builder species.
Communication networks are likely via line-of-sight laser or some means we can't comprehend, so there's no transmissions for us to pick up. Hundreds of millions in number around each star, they're still too wispy to show up at distance as much more than asteroid fields or protoplanet belts. Being self-sufficient, it's no big deal when one colony decides to make the long, slow journey to the next uninhabited star. There, they get busy populating the colonies pre-built by robots sent ahead. The universe is old enough that there has been time for every star in the galaxy to be homesteaded by now.
We can get started by dismantling our own moon for material, moving on to Mercury and Mars's moons (planets are too big and unhealthy for our biology) until all of the available floating rock has been utilized. The colonies aren't made of girders and sheet steel. They're built by sintering crushed rock in the beam of focused sunlight, building up the superstructure like a gargantuan 3D printer. To simplify energy collection, the second or third generation of colonies are probably towed close to the sun, to minimize the size of PV panels needed.
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We can get started by dismantling our own moon for material,
Don't you think we might want to keep it around for tides? Let's just use the asteroids, and maintain the planet as a park or something.
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It will take millions of years to actually dismantle the moon, so Earth and its tidepool crabs are safe in the long run. We need to start with the moon since it's 12 orders of magnitude closer to home than anywhere else. Good practice for a few centuries. Local transportation can be done efficiently through orbital skyhooks. Then, Mercury is next because power is so accessible there. Other moons and asteroids come later since energy would be harder to collect to run operations.
There's not going to be any te
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We do not need Mars! We only need its moons - as an afterthought, at that. Mars is too light to provide proper gravity, too cold, and atmosphere too thin to protect from radiation and meteors. We cannot and would not want to live there. Ya gotta get your head out of the 1950's scifi assumption of living on alien planets. We have Earth, and we'll have manufactured orbital habitats.
Re:Universe teeming with O'Neil Colonies (Score:5, Insightful)
Getting to a technological level is hard. (Score:5, Insightful)
Just some of the things that had to happen for us to be where we are now:
1) Life had to evolve
2) Multicelluar life had to evolve (this took a billion years after life itself arose so is probably not a forgone conclusion)
3) Life had to climb out of the oceans (dolphins might be smart but they won't be building any rockets with their flippers anytime soon)
4) Suitable intelligence had to evolve. Had it not been for the asteroid the dinosaurs would still be in charge.
5) Humans had to survive numerous climate changes and if the genetics is to be believed we almost died out and everyone today comes from a very small population who made it.
6) Farming had to be created to allow people to do something other than hunting and gathering.
7) For the industrial revolution plenty of freely available energy had to be lying around near the surface - ie coal. You can't melt iron with wood fires.
8) Someone had to invent radio.
I'm sure there are dozens of other things that could fit inbetween those points but my basic point is that a technological civilisation than can broadcast information out from his own planey is very VERY unlikely. IMO we could well be the only one surrounded by planets full of the equivalents of bacteria and jellyfish but little more.
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You can't melt iron with wood fires
Not in its raw form, however you can make charcoal from wood (burn it with insufficient oxygen) and then use that to smelt iron. The requirement is concentration of energy, but once you have one energy source then eventually you can concentrate it. You can smelt iron in a solar furnace too, though you need to make a lot of glass to a fairly high standard to do it.
IMO we could well be the only one surrounded by planets full of the equivalents of bacteria and jellyfish but little more.
The point of TFA is that this is unlikely. Without photosynthesis, early life here would have experienced a run-away greenhouse effect and died
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Without the right balance after photosynthesis evolved, the oxygen content of the air would have become high enough to kill off all life.
No. Absolutely not. It would have become high enough to kill off most life. Developing photosynthesis is the hard part. After that, there's a lot more organic matter to work with, and a lot more can happen. Something will mutate to adapt to the new conditions, which are not uniform across the globe.
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"however you can make charcoal from wood (burn it with insufficient oxygen) and then use that to smelt iron. "
Yes, fair point. However there simply weren't enough trees around to do it - even in tudor times entire forests had to be grown just for ship wood - which is why the industrial revolution didn't really get going until mass coal production started.
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Except by that measure, we too are fantastically unlikely.
Humans are made up of hundreds of millions of specialized cells which, in the scant 3-ish billion years since prokaryotes showed up, had to learn to cooperate synergistically. And "learn" in a non-deterministic sense: basically they had to mutate (randomly) into combinations (randomly) and then be stressed (randomly) such that their offspring would demonstrate a competitive advantage...to the order of a hundred million cooperating.
If you think about
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All it takes is the right kind of evolutionary stress until civilization can take over. And, as odd as this may sound, religion. It's the only sensible way you can make more than 10 people work together without a strong cultural history in legal proceedings.
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Just some of the things that had to happen for us to be where we are now:
This is an interesting list, and as you note, there are all sorts of "other things that could fit in between those points."
However, your conclusion CANNOT follow, i.e., a technological civilization that can broadcast information is "very VERY unlikely." You have no basis to say it is "unlikely" nor "likely," because we have one data point -- Earth. One cannot extrapolate from one data point.
And that's why articles like this one always bug me a bit. "Researchers Say the Aliens Are Silent Because They
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They might have done, but they didn't manage it in 200m years and their descendents the birds haven't managed it since (ok crows, but even they're no Einsteins) so I don't think they genetically had what it takes.
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"Step 2 may not be needed. Maybe you can have an intelligent giant single cell organism that can build radios."
And step 8 is important only for external detectability. It's totally possible for a species to have gone directly to fiber.
This and other reasons (Score:5, Interesting)
I think there are two other points to consider: First, life and even intelligent life does not necessarily mean technology, or technology at an industrial scale. Maybe just THIS is very, very rare, with civilisations going this way separated by enormous gulfs of time and space. And maybe the universe is full of planets with aliens that have some sophisticated culture, but not at an technological scale that would lead to us being able to detect them.
Then there's the bottleneck of how long a species can sustain a lifestyle of full-scale industrial technology. Without forking out into space as soon as they can resources will be depleted very soon and then it's too late. Either that culture will end then or will (have to) become much more efficient and low-key, which again lowers the chances of us detecting anything.
I mean, one very useful aspect of thinking about this is thinking about what is going on here, not there. How long can we sustain this and what do we have to do to sustain it? Maybe we will learn how things tend to go with industrial-scale technological civilisations very quickly, even if too late...
Is this Slashdot... (Score:4, Interesting)
Or National Enquirer ?
Same here with low CO2 levels (Score:2)
Without the industrial revolution CO2 may have continued its decline and eventually become too low to support life. 150ppm seems about the range where some plants start dying. We got to 180 ppm. Digging up an burning coal helped raise this amount back to a sustainable level.
We really have no clue (Score:2)
Communication (Score:2)
We don't even listen out for SOS morse messages any more, and that was only around for a hundred years or so.
Any method of contacting an advanced civilisation isn't going to be listened for for more than a few generations before its obsolete and nobody's on the other end anyway. Like trying to send a fax will be in a few decades, or how pagers are all-but-dead, and how the first generation of mobile phones was largely incompatible with modern standardised SIMs, frequencies, codecs, etc.
I don't know what we
Nah. (Score:2)
No, aliens are silent because of time (Score:2)
Even these researchers don't understand the concept of time on a galactic scale. We've been around for a mere fraction of a second in terms of time scale. We haven't been around long enough for aliens to find us, or us to find them. It's why endeavors like SETI are, well, a waste of time.
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The galactic scale actually helps the pro-alien viewpoint. There are so many billions of planets in the galaxy that we would expect them to spawn life. Many systems in our galaxy are far older than Earth [wikipedia.org]. By the time the Earth was formed, the linked solar system had already had a chance to evolve from accretion disk->Kardashians.
And yet the galactic scale is no impediment to colonization. Assuming a 0.0025*c travel speed, it would take only 50 million years to colonize the galaxy [sentientdevelopments.com]. That's nothing in
Don't you really mean (Score:2)
"Researchers make wild ass fucking guess" because that's pretty much all it is when you have a sample size of one.
In this case I'd assert that the person sitting next to you on the bus has nearly the same chance of being right, so clothing their opinion in the false-authority of calling them researchers is rather misleading.
Anthills (Score:2)
We are not contacted because our civilization is likely not at all unique and not at all interesting to entities capable of contacting us.
Idle speculation ... (Score:2)
This sounds an awful lot like the discussion surrounding habitable planets 25 years ago. There really wasn't enough to raise the discourse above idle speculation because we were dealing with a sample of one (the solar system). The situation wasn't much better shortly after the discovery of exoplanets since the sample was incredibly biased.
The situation for planetary atmospheres is similar today. We have an incredibly small sample of planets where we have studied the atmosphere in any detail (again, the s
What's your sample size? (Score:2)
If it isn't greater than one, your blowing smoke out your ass.
Daisy World (Score:2)
also (Score:2)
A non-traditional response to the FP (Score:3)
Consider this: particle physics shows us that entangled observation (not to be confused with human or intelligent observation) ties past and future events together into a causative vector of influence.
Extrapolating from this using entangled observation similar to Einstein-Rosen bridges between quantum events suggests (mathematically) that there is a correlation between frames of references in real-space once a chain of events is initiated.
This would have the effect of linking independent causative frames such that the 'arrow of time' would diverge, probabilistically, between relative frames.
Or, attempting to explain this analogically:
The light from a distant star contains a tremendous amount of observable information about a star, and a limited amount of information about exoplanets (Doppler shift, chronographic direct imaging, etc...). As technology advances, however, it should be possible to tease out (observe) direct evidence of extrasolar life from this meager data due changes over time to how life changes a planetary atmosphere (specific to biome, but similar divergence vectors).
Depending on how one interprets causative entangled observation, this could actually have a strong anthropic effect on life. Evidence that alien life, intelligent or not, exists on an exoplanet would strongly influence the actions of any intelligent species towards visiting and exploring the planet. This would be very close to a strong motivational influence towards any intelligent social network, yielding a high probability outcome of events.
Depending on distance between planets and assuming that technological development is generally rapid, there becomes a high probability chance that any technological species would, inadvertently, directly affect the development (probably adversely) of all emergent evolutionary biomes within observational range.
As a species matures, they would probably realize this at some point, and take one of two divergent vectors: Some level of apathy (no empathy, just settle habitable planets or destroy competition) or avoidance (let them develop, don't interfere). Extrapolating those two motivational vectors, it's likely that there are those that would visit for nefarious reasons, and likely that there are those that would seek to prevent that type of interference due to social morays based on the above principles.
Pointless and Useless Speculation (Score:4, Insightful)
Even if there were advanced civilizations on only 1% of all the planets, that would still be millions or more.
To believe there are no other advanced civilizations out there, that they are somehow obligated to come pay us a visit, or that they blew themselves up, is pretty fucking arrogant of us.
When you move into a new neighborhood and the neighbors don't come to visit you, that doesn't mean they don't exist
Re:Pointless and Useless Speculation (Score:4, Funny)
Obligatory [imgflip.com]
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Even if there were advanced civilizations on only 1% of all the planets, that would still be millions or more.
Exactly. Even if it was 1/100th of a percent we'd be talking millions, if not billions.
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To believe there are no other advanced civilizations out there, that they are somehow obligated to come pay us a visit, or that they blew themselves up, is pretty fucking arrogant of us.
It's not just arrogant, it's statistically idiotic. The mind-numbing enormity of the numbers involved means that even with extremely pessimistic projections there are almost certainly billions of planets with advanced civilizations in the universe.
Billions of galaxies, with each one of them having billions of potentially life-supporting planets...the suggestion that there's no one else out there is ignorant beyond belief
Re:Pointless and Useless Speculation (Score:5, Interesting)
Even if we're not, look at our development. Even if another civilization was on par with us, they could not even communicate with us if they wanted.
Whenever the topic gets to alien life forms, everyone assumes that the aliens must be advanced compared to us and have mastered interstellar, maybe even intergalactic, travel. Says who? Who says it's even possible to do this akin to various SciFi movies? What if the aliens would have to use newtonian physics to get here? Even if they developed 20 LJ away their journey would take centuries.
Our development from "duh, me make fire" to "duh, remote control is broken, need new TV" took about 10,000 years. And we're still in no position whatsoever to fly to any other star than our own. Hell, even reaching the next planet is something we've been working on for half a century now. And every time we actually manage to get a non-manned robot there on a one way trip we celebrate it hugely. What makes us think that anyone else in this universe is actually so far ahead of us to be able to fly about between the stars AND have the hubris to assume that someone this advanced would actually want to have anything to do with us?
Re:Pointless and Useless Speculation (Score:5, Insightful)
Our development from "duh, me make fire" to "duh, remote control is broken, need new TV" took about 10,000 years. And we're still in no position whatsoever to fly to any other star than our own. Hell, even reaching the next planet is something we've been working on for half a century now.
All of the time spans you give here are inconsequential when compared to the age of the universe. Even if it took us 10 million years to go from current technology to quick interstellar travel, if life is not unique to Earth then we are either the first sapient species or the only one. 10 million years is simply not a long time at this scale.
Star systems started forming within a billion years of the big bang (source [extremetech.com]), over 13 billion years ago, and it took less than 5 billion years for life to reach its current state on Earth since its creation. That leaves over 8 billion years for potential sapient civilizations to emerge before us. One physist claims it would take 5 - 10 billion years [vice.com] to colonize the entire known galaxy even with current propulsion technology.
We may find out life is so rare we are either the only ones or among only a few dozen inhabited planets. But if life is common at all, it is very likely there are intergalactic civilizations which have been around for billions of years. That is what leads many people, myself included, to believe life is an extreme rarity.
What makes us think that anyone else in this universe is actually so far ahead of us to be able to fly about between the stars AND have the hubris to assume that someone this advanced would actually want to have anything to do with us?
We have people on our planet devoting their careers to researching earth worms, so it doesn't take hubris to believe that out of potentially near infinite civilizations there may be some who have scientists interested in studying pre-interstellar civilizations like us.
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First generation stars have no heavy elements. Hence first gen solar systems won't have the chemistry for life.
Re:Pointless and Useless Speculation (Score:5, Insightful)
> ND have the hubris to assume that someone this advanced would actually want to have anything to do with us?
Because it isn't hubris. Humans are interesting. Perhaps not to some rock-being, or whatever space opera alien is in your head that is Sooooooooo advanced that they find us boring, but to SOMETHING at SOME TIME. You posit a pretty strange concept: that if there's a zillion advanced lifeforms out there, that literally NONE of them would find Earth, or humanity, interesting in the slightest. That's the problem: it's trivial to imagine a species "so advanced" that we are very very boring to them. It's much harder to imagine that the universe is EXCLUSIVELY filled with these beings.
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Basically, the argument is that aliens are probably not on exactly the same "blink of an eye" as we are. As you noted, from discovering fire to space travel took us only about 10,000 years, or 0.00025% of the time life has existed on our planet. And only the last hundred years or so would have allowed for interstellar communication. So you shouldn't expect more than a 0.0000025% chance that we are able to contact aliens less advanced than us. The chance is further reduced if you assume the more advanced ali
Re:Pointless and Useless Speculation (Score:5, Insightful)
The elephant in the room is that cosmological distances are unbelievably large. The energy expenditure and sheer material cost of building something that can move any further than the outer reaches of a solar system is so huge as to make almost pointless even if possible. Currently it is blind faith rather than physics that suggests that the human race will ever be able to visit even the nearest star.
What is slightly more puzzling is that if the galaxy is teaming with technological civilizations we can detect no sign of their signals. Though this may just be the inadequacy of current technology. Discriminating against stars for any electromagnetic signal even for a focused laser is probably beyond our means at the moment. I have not seen any analysis of this from people like the SETI institute, has anyone seen this analysis?
Re:Detect without Visiting (Score:5, Insightful)
True but usually you can see some signs that there are neighbours there such as hearing their car or the music they are playing. In our case we have not heard anything so either we are not listening in the right way, they make practically no 'noise' or they don't exist at least close by.
When humans first invented radio, we broadcast strong simple signals because our technology was primitive. These signals would be detectable from very long distances away. But we are rapidly moving to much weaker and complex transmissions. This has the benefit of using far less power, and has much greater bandwidth. But it also makes the signal harder to detect and almost indistinguishable from background noise. There was only a 150 year window from when we started to transmit, and when our transmissions became indistinguishable from static. Compared to the age of the Universe, that window was a very tiny blip.
wild, speculation like this is a waste of time
Wasting time on wild speculation is the whole point of Slashdot.
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I can't tell whether I agree or disagree with you, but at least in what I quoted, you have
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Exploring Earth is a bit like using a toothbrush. Once someone else has done it, you kinda don't wanna do it anymore.