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Life on other planets would likely be brief and become extinct very quickly

59 points by barce 11y ago

Zikes 11y ago
There sure are a lot of confident yet highly speculative declarations about life in that article, in spite of the fact that we currently only have a sample size of one.
- chris_wot 11y ago
  Really? Which declaration in particular are you referring to?
  - Zikes 11y ago
    > Early life is fragile > The aliens are silent because they are extinct > new life would commonly die out due to runaway heating or cooling on their fledgling planets I'm not disputing the science or studies the article refers to (I'm far from qualified for that), I believe that models of plausibility are an important part of the process, but as with most science journalism they just can't help turning them into some sort of "absolute" statements.
    - chris_wot 11y ago
      Good point, missed those statements (forest for the trees I guess). Those are quite unfortunate!
- interdrift 11y ago
  There's also the Fermi paradox which makes those speculative declarations somewhat believable..
phreeza 11y ago
My personal lesson from the fermi paradox and the drake equation in particular is that we humans are terrible at grasping very small probabilities. Intuition completely fails when we have to decide if something has the probability 10^-5 or 10^-50, which makes sense because for almost all practical purposes both are almost zero in most situations, but for edge cases like the drake equation they make all the difference.
- ekianjo 11y ago
  Its not just difficult to grasp. Its very difficult to estimate in the first place since have very little data at hand to make any call. For example we may take 1/9 for the probability of life appearing in a given planetary system, but we have no idea if this is representative or not of usual probabilities or if our system is exceptional in any way.
netinstructions 11y ago
Is there anything revelatory in this article? I didn't see any links or references to new papers/ideas, but some Googling returned this 2016 PDF[1] titled 'The Case for a Gaian Bottleneck' by Aditya Chopra from ANU. There's been discussion in the past[2][3] about these 'Great Filters' that prevent life from occurring everywhere in the universe. [1]http://adi.life/pubs/ChopraLineweaver2016.pdf http://adi.life/pubs/ChopraLineweaver2016.pdf [2]http://mason.gmu.edu/~rhanson/greatfilter.html http://mason.gmu.edu/~rhanson/greatfilter.html [3]http://waitbutwhy.com/2014/05/fermi-paradox.html http://waitbutwhy.com/2014/05/fermi-paradox.html
- ekianjo 11y ago
  Same impression here, nothing new in this article. Its part of numerous ideas discussed before. And there is no hard evidence to support if this is the main bottle neck or not.
- melipone 11y ago
  What I got was that the rapid emergence of biological feedback was essential for regularizing climate which in turn enabled life on earth to evolve. In a way, life itself enabled life on earth. It's the rarity of this emergence that is important rather than the rarity of intelligent life. Another thing I got is that life itself will destroy life the way climate change is going :-)
civilian 11y ago
I've been reading The Vital Question by Nick Lane, where he puts forth some theories about the origin of eukaryotes, and life in general. It does make it seem that abiogenesis and eukaryote-genesis are much more difficult than we give them credit for. So in the Drake Equation, I think that F[L] is probably pretty low. And because eukaroyte genesis is difficult and only happened once (and it took a billion years of bacteria & archea hanging out before we got a eukaryote), and eukaryotes are a prereq for multi-cellular organisms and thus intelligent life, F[i] is also really low. http://www.amazon.com/The-Vital-Question-Evolution-Origins/dp/0393088812 http://www.amazon.com/The-Vital-Question-Evolution-Origins/d...
- monk_e_boy 11y ago
  Panspermia is one solution to this.
  - shawndumas 11y ago
    All problems [in philosophy] can be solved by another level of indirection...
    - monk_e_boy 11y ago
      Ha! But it does solve the 'this rare event happened here on Earth but it is very unlikely to happen anywhere' because those little single cells came here from somewhere else. That source infected millions of planets. It moves the problem of starting everywhere to starting in one place (more likely)
      - AnimalMuppet 11y ago
        Getting it to occur once is more likely than getting it to occur many times. However, it does give you a new problem: making cells that can survive hard vacuum, radiation, and extreme cold, for millenia (at least), and still be viable when they reach a new planet. We're not talking speed-of-light propagation here. We're probably not even talking 0.01 c. So even to the nearest neighboring star is probably thousands or tens of thousands of years. In vacuum. In extreme cold. Without even photosynthesis to provide energy. Yeah, I'm kind of skeptical of this actually working.
orf 11y ago
People always talk about how vast space is, but rarely about how vast time is. We've been looking for life for the last what, 60 years or so? It seems like not only is space so vast which makes finding evidence of life hard, but this is made even harder by the small volume of time we are likely to be around to try and observe in the grand scheme of things. Alien life has to be relatively close in terms of distance as well as time. What if our closest alien life became discoverable (started emitting radio signals or other signs) a million years from now? Would we be around to see it?
- ceejayoz 11y ago
  > Would we be around to see it? And how long does an average civilization broadcast radio? On the "life is safe" end of the spectrum, maybe there's much better technology to be discovered. On the "life is dangerous" end, maybe you learn pretty fast not to broadcast your location to the galaxy.
  - JohnDotAwesome 11y ago
    Reminds me of the book, The Three Body problem
  - orf 11y ago
    > maybe there's much better technology to be discovered Obviously we don't have much to draw on, but it seems like our technological growth looks a bit exponential. I'd imagine a civilization that has been around for a million years would have discovered a hell of a lot of technology - but a million years is a blip in 13.82 billion years, the age of the Universe. It's like 0.001% if I've got my maths right.
- kposehn 11y ago
  Excellent point. I think that one advantage of interstellar distance is we can effectively look back in time a great distance, so in effect we don't have a visible radius, but a combination of time and distance. We can see thousands of light years back in time, thousands of light years away. However, we don't have that picture of Tau Ceti at 11 light years away. Perhaps thousands of years ago there was a civilization there that flourished and died - and we'll never know because their signs of life are outside our distance/time perception. A graph of Time/distance would be Time one axis, distance on the other and a diagonal line stretching up and to the right, showing what we could see at any given time. Thoughts? [edit: comment formatting ate my pretty ascii chart]
interdrift 11y ago
Imagine how easily we can also become extict and even our most powerful technology isn't powerful enough to save us. Imagine a big explosion in our galaxy , like that supernova that happend recently. We could die out like ants. We should be progressing faster...
- coderdude 11y ago
  We're already progressing at breakneck speed. The last 10,000 years saw us go from stone tools to the Samsung S6.
  - JohnDotAwesome 11y ago
    And in the last couple of years, from the iPhone 6 to the iPhone 6s!
reasonattlm 11y ago
No answer to the Fermi Paradox works if it requires all aliens to uniformly come to the same end state or satisfy some boundary condition without exception. All it takes is the one exception, one small group in one suitably advanced civilization, and you have self-replicating probes building an expanding wave of computronium, dismantling even the stars themselves as soon as the economics favor a better use for that matter. Such as more computronium. The Fermi Paradox is more the Wilderness Paradox: why is everything, everywhere we look, wild and unmodified? Why are there still stars, when a simple economic analysis of our future tells us that we will tear them down in favor of more efficient arrangements of matter and energy? https://www.exratione.com/2015/05/the-cosmological-noocene/ https://www.exratione.com/2015/05/the-cosmological-noocene/ "Per our present understanding of physics and intelligent economic activity, we will turn every part of the great span of the universe into our descendants if not diverted or stopped by some outside influence, stars and all. The cosmological noocene, an ocean of intelligence. That the natural universe remains present to be used by us indicates that something is awry, however, that some vital and important understanding is missing, and as a species we are still just making the first fumbling explorations of the bounds of the possible with regards to what it is that we don't know."
- Florin_Andrei 11y ago
  > dismantling even the stars themselves It's unclear whether that's actually feasible from an energy balance perspective. You'll need a lot of energy to re-arrange things on that scale. Each star is already sitting at the bottom of its own local energy well. Maybe the far future will discover radically new ways to produce energy - but until then, this whole thing about the wave of computronium flooding the universe is pure speculation.
  - reasonattlm 11y ago
    Agreed, but stars are very fragile in some ways; surprisingly small disruptions in some of their transitional layers can cause novas. Stellar modeling is entertaining in that way. So in place of "dismantle star" perhaps "provoke extreme mass loss" would be a more obviously net energy-positive goal for the engineers. Still, one should run the back of the envelope calculations on what you'd have to do with a stellar mass to produce greater energy than it emits in its current form, and whether the difference can be enough to make it a net positive to nova the star. My intuitive belief is that the difference in efficiency of use of materials can be huge, more than enough to justify large investments in stellar engineering at the stage when technologies means molecular nanotechnology plus nucleosynthesis: factories capable of taking in hydrogen and turning out anything.
nsgoetz 11y ago
So life won't always find a way?
givan 11y ago
I wonder why on this subject everyone overlooks two major events witnessed by thousands of people some of which former military pilots and instead focus on science fiction scenarios. https://en.wikipedia.org/wiki/Belgian_UFO_wave https://en.wikipedia.org/wiki/Belgian_UFO_wave https://en.wikipedia.org/wiki/Phoenix_Lights https://en.wikipedia.org/wiki/Phoenix_Lights People try to explain these events in all kind of ways avoiding the most obvious one no matter what. Is it fear? the lack of recognition by authorities? I never understood why people will talk freely about aliens in the universe but aliens here is always a taboo or a subject of ridicule no matter the evidence.
- frozenport 11y ago
  I think its more likely the government was testing military equipment.
  - givan 11y ago
    > Witnesses claim to have observed a huge V-shaped (several football field sized), coherently-moving dark UFO (stars would disappear behind the object and reappear as it passed by), producing no sound, and containing five spherical lights or possibly light-emitting engines Do you really think the military has this kind of technology?
    - leppr 11y ago
      Do you think there used to be dragons roaming the earth?
      - givan 11y ago
        Do you still think the earth is flat? This is how it sounds when you try to ridicule something that you don't know or probably don't want to know for various reasons, you should read more on the subject with an objective mind.
        leppr 11y ago
njharman 11y ago
Compared to age of Galaxy, Life on this planet has been brief. Also, aren't something like 99.99% of all species extinct?
- vectorjohn 11y ago
  Not really, life on Earth has existed for about 26% of the age of the universe (about 3.5 billion years). And we have good reason to expect that life cannot arise before a certain time because we have to go through a cycle or two of supernovas ejecting useful elements into their surroundings. If you meant intelligent life, then nevermind :)
putlake 11y ago
Liu Cixin's The Dark Forest, the second book in his 3-body problem trilogy, posits a similar philosophy: resources are limited so civilizations annihilate other civilizations. So if an alien civilization knew about earthlings, they will destroy earth ASAP if they are capable, lest the earthlings come after their resources. This is also why some people believe we should not try to make contact with intelligent alien life. They believe broadcasting our location is dangerous.
- vectorjohn 11y ago
  It just doesn't make any sense. Resources are limited, sure, but they're not scarce. In fact, they might not be limited even. If something can afford to come to Earth, they can afford to get unlimited resources from anywhere. Unless you're positing it's from one of our nearest stars and then just happen to be coming to Earth as a last ditch effort or something. I mean, scenarios can be imagined where an alien would want to destroy life on Earth, but they seem far fetched.
- skybrian 11y ago
  Except that we have a very big moat. I liked David Brin's take on this in Existence, where anything sent such a long way is likely to resemble a virus.
3rdkind 11y ago
Aliens jump sideways in - and out. Forget about distance.
Animats 11y ago
Industrial civilization may not last very long. Industrial civilization on Earth is only about 200 years old. A useful starting point is the first time a railroad train carried paying passengers. There were earlier demos and prototypes, but think of that as the moment the Industrial Revolution got out of beta. Progress up to then was very slow. Progress after that was very fast. About 75 years ago, progress reached the point that a substantial dent could be made in the planet's resources. Until then, human activity just wasn't large scale enough. Now, we can see the end in sight for many resources. On a scale of centuries, most mineral resources run out. The high-power, heavy industry phase of life may have an expiration date that's closer in time than the founding of Oxford University.
- nickbauman 11y ago
  > About 75 years ago, progress reached the point that a substantial dent could be made... Controversial assertion. There's a lot of evidence that we've been able to rank on the level of forces of nature for quite a while now. The disappearance of megafauna, the desertification of Western China and Saharan Africa. There's even evidence that the Amazon rainforest may have been a massive human silviculture project that had been going on for 10,000 years.
givan 11y ago
Our view of life in the universe is subjective, we compare it with the only place we know it exists, earth, probably life exists in many forms not limited to how we know it or how we would expect it to evolve so probably not all life might be brief how earthers might think. We are amazed how life exists in the most hostile places on earth and how it was able to adapt to very harsh conditions, probably life in universe is also full of surprises.
theboywho 11y ago
The problem with this reasoning is that it considers this to be true: if intelligent life exists, we are gonna be able to understand its intelligence. What if there exist an intelligent life, so intelligent that their level of intelligence compared to ours is like comparing ours with...cats. We all know small genetic mutations can have huge impact. So huge they might just be technically/biologically out of reach. So maybe an intelligent life exists out there, but they are so ahead of us that we are not even capable of understanding how. Like a little cat watching a car thinking maybe it's an animal.
- kposehn 11y ago
  > So maybe an intelligent life exists out there, but they are so ahead of us that we are not even capable of understanding how. Like a little cat watching a car thinking maybe it's an animal. So true. We are really bad at looking at things outside the lens of our own experience. Why would life evolve in exactly the same fashion? Would it even have DNA as we know it? There is life that could form in ways we cannot even perceive - intelligence of a type that is so completely alien that neither could every notice or understand the other. The universe may simply be filled with life, but because it evolves so differently it may simply be impossible to see most of it.
PaybackTony 11y ago
A series of unproven theories as a basis for a new theory that further unproven theories can be based on. The cornerstone of modern science. There really needs to be more documented, observable data before there can be any remotely credible theory about how abundant or desolate our universe is of life. Using such observable data (we know the name) we could only surmise that in 100% of solar systems with a similar sun, bearing a planet at an adequate distance from it's sun, will not only support life, but would have life. Common sense[?] would dictate that's very unlikely, but there's no scientific basis yet to even theorize otherwise until we can find a way to get that data. To come up with absolutes about planets such distances away is foolish given we don't know half a shit about the planets right next to us.
- ZanyProgrammer 11y ago
  It seems like a lot of SETI/astro biology is more speculation than science, i.e. something that can be disproved or reproduced.
nickbauman 11y ago
The book Rare Earth covers this topic throughly. The conclusion they come to is that complex, multicellular life is likely extremely rare in the universe. But simple, microbial life may be much more common than we think. http://www.amazon.com/Rare-Earth-Complex-Uncommon-Universe/dp/0387952896 http://www.amazon.com/Rare-Earth-Complex-Uncommon-Universe/d...
- yongjik 11y ago
  I didn't find the book very persuasive. The authors basically take everything that is (or might be) uncommon about the Solar System, and somehow turns them into an argument on why we are so lucky to have them. E.g., we have big Jupiter. We don't know exactly what it does, but it might have helped the Earth survive its early days. Therefore, it might be the case that the rise of complex life needed Jupiter. Yadda yadda, multiply a dozen of these things, and suddenly life on Earth looks like an incredible stroke of luck. The problem is, we don't know enough to make that verdict. What if the existence of Jupiter actually postponed the rise of life by sending big comets along our way? I enjoyed "Life Everywhere" by Darling much more, though it is probably too dated to recommend in 2016. (Astrobiology is a rapidly changing field, I suppose.)
  - nickbauman 11y ago
    That's interesting remember the book explaining Jupiter had a specific influence on earth's ability to develop complex life in that its size and position made it essentially prevent a lot of comets and dangerous asteroids from hitting earth by simply getting in their way.
    - yongjik 11y ago
      I think I wrote my argument rather poorly. Let me try again: I could buy that Jupiter in our particular Solar System had the effect of clearing asteroids in the Earth's orbit. However, that doesn't automatically mean that Jupiter was essential. What if, say, Jupiter's presence in the early days of the solar system prevented these asteroids from coalescing further, resulting in the presence of the asteroids in the first place? Or what if it didn't matter in the long run anyway? Okay I just pulled that out of thin air, but what I'm saying is that there's too many unknowns to declare we needed Jupiter for life. The authors cherry-picks arguments that support their cause. Also bear in mind that this book was written in 2003, when we knew less than a dozen extrasolar planets and, IIRC, basically none looked like our Solar System (because the instruments weren't good enough to detect such systems). Even now, I don't think we know enough about planetary systems to confidently say whether Earth-like systems are common or rare.
pklausler 11y ago
I am convinced that we're the first/only space-capable species in our galaxy by the simple absence of killer self-replicating interstellar robots. I'm serious. Anything that's remotely possible becomes inevitable on these astronomical scales, and all it takes is one jerk making one self-replicating killer robot and that's it for life for the rest of time in the galaxy.

59 points by barce 11y ago

Zikes 11y ago

There sure are a lot of confident yet highly speculative declarations about life in that article, in spite of the fact that we currently only have a sample size of one.

chris_wot 11y ago
Really? Which declaration in particular are you referring to?
- Zikes 11y ago
  > Early life is fragile > The aliens are silent because they are extinct > new life would commonly die out due to runaway heating or cooling on their fledgling planets I'm not disputing the science or studies the article refers to (I'm far from qualified for that), I believe that models of plausibility are an important part of the process, but as with most science journalism they just can't help turning them into some sort of "absolute" statements.
  - chris_wot 11y ago
    Good point, missed those statements (forest for the trees I guess). Those are quite unfortunate!
interdrift 11y ago
There's also the Fermi paradox which makes those speculative declarations somewhat believable..

phreeza 11y ago

My personal lesson from the fermi paradox and the drake equation in particular is that we humans are terrible at grasping very small probabilities. Intuition completely fails when we have to decide if something has the probability 10^-5 or 10^-50, which makes sense because for almost all practical purposes both are almost zero in most situations, but for edge cases like the drake equation they make all the difference.

ekianjo 11y ago
Its not just difficult to grasp. Its very difficult to estimate in the first place since have very little data at hand to make any call. For example we may take 1/9 for the probability of life appearing in a given planetary system, but we have no idea if this is representative or not of usual probabilities or if our system is exceptional in any way.

netinstructions 11y ago

Is there anything revelatory in this article? I didn't see any links or references to new papers/ideas, but some Googling returned this 2016 PDF[1] titled 'The Case for a Gaian Bottleneck' by Aditya Chopra from ANU. There's been discussion in the past[2][3] about these 'Great Filters' that prevent life from occurring everywhere in the universe. [1]http://adi.life/pubs/ChopraLineweaver2016.pdf http://adi.life/pubs/ChopraLineweaver2016.pdf [2]http://mason.gmu.edu/~rhanson/greatfilter.html http://mason.gmu.edu/~rhanson/greatfilter.html [3]http://waitbutwhy.com/2014/05/fermi-paradox.html http://waitbutwhy.com/2014/05/fermi-paradox.html

ekianjo 11y ago
Same impression here, nothing new in this article. Its part of numerous ideas discussed before. And there is no hard evidence to support if this is the main bottle neck or not.
melipone 11y ago
What I got was that the rapid emergence of biological feedback was essential for regularizing climate which in turn enabled life on earth to evolve. In a way, life itself enabled life on earth. It's the rarity of this emergence that is important rather than the rarity of intelligent life. Another thing I got is that life itself will destroy life the way climate change is going :-)

civilian 11y ago

I've been reading The Vital Question by Nick Lane, where he puts forth some theories about the origin of eukaryotes, and life in general. It does make it seem that abiogenesis and eukaryote-genesis are much more difficult than we give them credit for. So in the Drake Equation, I think that F[L] is probably pretty low. And because eukaroyte genesis is difficult and only happened once (and it took a billion years of bacteria & archea hanging out before we got a eukaryote), and eukaryotes are a prereq for multi-cellular organisms and thus intelligent life, F[i] is also really low. http://www.amazon.com/The-Vital-Question-Evolution-Origins/dp/0393088812 http://www.amazon.com/The-Vital-Question-Evolution-Origins/d...

monk_e_boy 11y ago
Panspermia is one solution to this.
- shawndumas 11y ago
  All problems [in philosophy] can be solved by another level of indirection...
  - monk_e_boy 11y ago
    Ha! But it does solve the 'this rare event happened here on Earth but it is very unlikely to happen anywhere' because those little single cells came here from somewhere else. That source infected millions of planets. It moves the problem of starting everywhere to starting in one place (more likely)
    - AnimalMuppet 11y ago
      Getting it to occur once is more likely than getting it to occur many times. However, it does give you a new problem: making cells that can survive hard vacuum, radiation, and extreme cold, for millenia (at least), and still be viable when they reach a new planet. We're not talking speed-of-light propagation here. We're probably not even talking 0.01 c. So even to the nearest neighboring star is probably thousands or tens of thousands of years. In vacuum. In extreme cold. Without even photosynthesis to provide energy. Yeah, I'm kind of skeptical of this actually working.

orf 11y ago

People always talk about how vast space is, but rarely about how vast time is. We've been looking for life for the last what, 60 years or so? It seems like not only is space so vast which makes finding evidence of life hard, but this is made even harder by the small volume of time we are likely to be around to try and observe in the grand scheme of things. Alien life has to be relatively close in terms of distance as well as time. What if our closest alien life became discoverable (started emitting radio signals or other signs) a million years from now? Would we be around to see it?

ceejayoz 11y ago
> Would we be around to see it? And how long does an average civilization broadcast radio? On the "life is safe" end of the spectrum, maybe there's much better technology to be discovered. On the "life is dangerous" end, maybe you learn pretty fast not to broadcast your location to the galaxy.
- JohnDotAwesome 11y ago
  Reminds me of the book, The Three Body problem
- orf 11y ago
  > maybe there's much better technology to be discovered Obviously we don't have much to draw on, but it seems like our technological growth looks a bit exponential. I'd imagine a civilization that has been around for a million years would have discovered a hell of a lot of technology - but a million years is a blip in 13.82 billion years, the age of the Universe. It's like 0.001% if I've got my maths right.
kposehn 11y ago
Excellent point. I think that one advantage of interstellar distance is we can effectively look back in time a great distance, so in effect we don't have a visible radius, but a combination of time and distance. We can see thousands of light years back in time, thousands of light years away. However, we don't have that picture of Tau Ceti at 11 light years away. Perhaps thousands of years ago there was a civilization there that flourished and died - and we'll never know because their signs of life are outside our distance/time perception. A graph of Time/distance would be Time one axis, distance on the other and a diagonal line stretching up and to the right, showing what we could see at any given time. Thoughts? [edit: comment formatting ate my pretty ascii chart]

interdrift 11y ago

Imagine how easily we can also become extict and even our most powerful technology isn't powerful enough to save us. Imagine a big explosion in our galaxy , like that supernova that happend recently. We could die out like ants. We should be progressing faster...

coderdude 11y ago
We're already progressing at breakneck speed. The last 10,000 years saw us go from stone tools to the Samsung S6.
- JohnDotAwesome 11y ago
  And in the last couple of years, from the iPhone 6 to the iPhone 6s!

reasonattlm 11y ago

No answer to the Fermi Paradox works if it requires all aliens to uniformly come to the same end state or satisfy some boundary condition without exception. All it takes is the one exception, one small group in one suitably advanced civilization, and you have self-replicating probes building an expanding wave of computronium, dismantling even the stars themselves as soon as the economics favor a better use for that matter. Such as more computronium. The Fermi Paradox is more the Wilderness Paradox: why is everything, everywhere we look, wild and unmodified? Why are there still stars, when a simple economic analysis of our future tells us that we will tear them down in favor of more efficient arrangements of matter and energy? https://www.exratione.com/2015/05/the-cosmological-noocene/ https://www.exratione.com/2015/05/the-cosmological-noocene/ "Per our present understanding of physics and intelligent economic activity, we will turn every part of the great span of the universe into our descendants if not diverted or stopped by some outside influence, stars and all. The cosmological noocene, an ocean of intelligence. That the natural universe remains present to be used by us indicates that something is awry, however, that some vital and important understanding is missing, and as a species we are still just making the first fumbling explorations of the bounds of the possible with regards to what it is that we don't know."

Florin_Andrei 11y ago
> dismantling even the stars themselves It's unclear whether that's actually feasible from an energy balance perspective. You'll need a lot of energy to re-arrange things on that scale. Each star is already sitting at the bottom of its own local energy well. Maybe the far future will discover radically new ways to produce energy - but until then, this whole thing about the wave of computronium flooding the universe is pure speculation.
- reasonattlm 11y ago
  Agreed, but stars are very fragile in some ways; surprisingly small disruptions in some of their transitional layers can cause novas. Stellar modeling is entertaining in that way. So in place of "dismantle star" perhaps "provoke extreme mass loss" would be a more obviously net energy-positive goal for the engineers. Still, one should run the back of the envelope calculations on what you'd have to do with a stellar mass to produce greater energy than it emits in its current form, and whether the difference can be enough to make it a net positive to nova the star. My intuitive belief is that the difference in efficiency of use of materials can be huge, more than enough to justify large investments in stellar engineering at the stage when technologies means molecular nanotechnology plus nucleosynthesis: factories capable of taking in hydrogen and turning out anything.

nsgoetz 11y ago

So life won't always find a way?

givan 11y ago

I wonder why on this subject everyone overlooks two major events witnessed by thousands of people some of which former military pilots and instead focus on science fiction scenarios. https://en.wikipedia.org/wiki/Belgian_UFO_wave https://en.wikipedia.org/wiki/Belgian_UFO_wave https://en.wikipedia.org/wiki/Phoenix_Lights https://en.wikipedia.org/wiki/Phoenix_Lights People try to explain these events in all kind of ways avoiding the most obvious one no matter what. Is it fear? the lack of recognition by authorities? I never understood why people will talk freely about aliens in the universe but aliens here is always a taboo or a subject of ridicule no matter the evidence.

frozenport 11y ago
I think its more likely the government was testing military equipment.
- givan 11y ago
  > Witnesses claim to have observed a huge V-shaped (several football field sized), coherently-moving dark UFO (stars would disappear behind the object and reappear as it passed by), producing no sound, and containing five spherical lights or possibly light-emitting engines Do you really think the military has this kind of technology?
  - leppr 11y ago
    Do you think there used to be dragons roaming the earth?
    - givan 11y ago
      Do you still think the earth is flat? This is how it sounds when you try to ridicule something that you don't know or probably don't want to know for various reasons, you should read more on the subject with an objective mind.
      - leppr 11y ago

njharman 11y ago

Compared to age of Galaxy, Life on this planet has been brief. Also, aren't something like 99.99% of all species extinct?

vectorjohn 11y ago
Not really, life on Earth has existed for about 26% of the age of the universe (about 3.5 billion years). And we have good reason to expect that life cannot arise before a certain time because we have to go through a cycle or two of supernovas ejecting useful elements into their surroundings. If you meant intelligent life, then nevermind :)

putlake 11y ago

Liu Cixin's The Dark Forest, the second book in his 3-body problem trilogy, posits a similar philosophy: resources are limited so civilizations annihilate other civilizations. So if an alien civilization knew about earthlings, they will destroy earth ASAP if they are capable, lest the earthlings come after their resources. This is also why some people believe we should not try to make contact with intelligent alien life. They believe broadcasting our location is dangerous.

vectorjohn 11y ago
It just doesn't make any sense. Resources are limited, sure, but they're not scarce. In fact, they might not be limited even. If something can afford to come to Earth, they can afford to get unlimited resources from anywhere. Unless you're positing it's from one of our nearest stars and then just happen to be coming to Earth as a last ditch effort or something. I mean, scenarios can be imagined where an alien would want to destroy life on Earth, but they seem far fetched.
skybrian 11y ago
Except that we have a very big moat. I liked David Brin's take on this in Existence, where anything sent such a long way is likely to resemble a virus.

3rdkind 11y ago

Aliens jump sideways in - and out. Forget about distance.

Animats 11y ago

Industrial civilization may not last very long. Industrial civilization on Earth is only about 200 years old. A useful starting point is the first time a railroad train carried paying passengers. There were earlier demos and prototypes, but think of that as the moment the Industrial Revolution got out of beta. Progress up to then was very slow. Progress after that was very fast. About 75 years ago, progress reached the point that a substantial dent could be made in the planet's resources. Until then, human activity just wasn't large scale enough. Now, we can see the end in sight for many resources. On a scale of centuries, most mineral resources run out. The high-power, heavy industry phase of life may have an expiration date that's closer in time than the founding of Oxford University.

nickbauman 11y ago
> About 75 years ago, progress reached the point that a substantial dent could be made... Controversial assertion. There's a lot of evidence that we've been able to rank on the level of forces of nature for quite a while now. The disappearance of megafauna, the desertification of Western China and Saharan Africa. There's even evidence that the Amazon rainforest may have been a massive human silviculture project that had been going on for 10,000 years.

givan 11y ago

Our view of life in the universe is subjective, we compare it with the only place we know it exists, earth, probably life exists in many forms not limited to how we know it or how we would expect it to evolve so probably not all life might be brief how earthers might think. We are amazed how life exists in the most hostile places on earth and how it was able to adapt to very harsh conditions, probably life in universe is also full of surprises.

theboywho 11y ago

The problem with this reasoning is that it considers this to be true: if intelligent life exists, we are gonna be able to understand its intelligence. What if there exist an intelligent life, so intelligent that their level of intelligence compared to ours is like comparing ours with...cats. We all know small genetic mutations can have huge impact. So huge they might just be technically/biologically out of reach. So maybe an intelligent life exists out there, but they are so ahead of us that we are not even capable of understanding how. Like a little cat watching a car thinking maybe it's an animal.

kposehn 11y ago
> So maybe an intelligent life exists out there, but they are so ahead of us that we are not even capable of understanding how. Like a little cat watching a car thinking maybe it's an animal. So true. We are really bad at looking at things outside the lens of our own experience. Why would life evolve in exactly the same fashion? Would it even have DNA as we know it? There is life that could form in ways we cannot even perceive - intelligence of a type that is so completely alien that neither could every notice or understand the other. The universe may simply be filled with life, but because it evolves so differently it may simply be impossible to see most of it.

PaybackTony 11y ago

A series of unproven theories as a basis for a new theory that further unproven theories can be based on. The cornerstone of modern science. There really needs to be more documented, observable data before there can be any remotely credible theory about how abundant or desolate our universe is of life. Using such observable data (we know the name) we could only surmise that in 100% of solar systems with a similar sun, bearing a planet at an adequate distance from it's sun, will not only support life, but would have life. Common sense[?] would dictate that's very unlikely, but there's no scientific basis yet to even theorize otherwise until we can find a way to get that data. To come up with absolutes about planets such distances away is foolish given we don't know half a shit about the planets right next to us.

ZanyProgrammer 11y ago
It seems like a lot of SETI/astro biology is more speculation than science, i.e. something that can be disproved or reproduced.

nickbauman 11y ago

The book Rare Earth covers this topic throughly. The conclusion they come to is that complex, multicellular life is likely extremely rare in the universe. But simple, microbial life may be much more common than we think. http://www.amazon.com/Rare-Earth-Complex-Uncommon-Universe/dp/0387952896 http://www.amazon.com/Rare-Earth-Complex-Uncommon-Universe/d...

yongjik 11y ago
I didn't find the book very persuasive. The authors basically take everything that is (or might be) uncommon about the Solar System, and somehow turns them into an argument on why we are so lucky to have them. E.g., we have big Jupiter. We don't know exactly what it does, but it might have helped the Earth survive its early days. Therefore, it might be the case that the rise of complex life needed Jupiter. Yadda yadda, multiply a dozen of these things, and suddenly life on Earth looks like an incredible stroke of luck. The problem is, we don't know enough to make that verdict. What if the existence of Jupiter actually postponed the rise of life by sending big comets along our way? I enjoyed "Life Everywhere" by Darling much more, though it is probably too dated to recommend in 2016. (Astrobiology is a rapidly changing field, I suppose.)
- nickbauman 11y ago
  That's interesting remember the book explaining Jupiter had a specific influence on earth's ability to develop complex life in that its size and position made it essentially prevent a lot of comets and dangerous asteroids from hitting earth by simply getting in their way.
  - yongjik 11y ago
    I think I wrote my argument rather poorly. Let me try again: I could buy that Jupiter in our particular Solar System had the effect of clearing asteroids in the Earth's orbit. However, that doesn't automatically mean that Jupiter was essential. What if, say, Jupiter's presence in the early days of the solar system prevented these asteroids from coalescing further, resulting in the presence of the asteroids in the first place? Or what if it didn't matter in the long run anyway? Okay I just pulled that out of thin air, but what I'm saying is that there's too many unknowns to declare we needed Jupiter for life. The authors cherry-picks arguments that support their cause. Also bear in mind that this book was written in 2003, when we knew less than a dozen extrasolar planets and, IIRC, basically none looked like our Solar System (because the instruments weren't good enough to detect such systems). Even now, I don't think we know enough about planetary systems to confidently say whether Earth-like systems are common or rare.

pklausler 11y ago

I am convinced that we're the first/only space-capable species in our galaxy by the simple absence of killer self-replicating interstellar robots. I'm serious. Anything that's remotely possible becomes inevitable on these astronomical scales, and all it takes is one jerk making one self-replicating killer robot and that's it for life for the rest of time in the galaxy.