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NASA estimates 1B ‘Earths’ in our galaxy alone

120 points by 51Cards 11y ago

sktrdie 11y ago
I really think that the great filter (of the fermi paradox) is behind us. Meaning, some stupefying rare event happened either when (i) life began in the first place, or when (ii) we evolved into advanced technological species. For (i) I remember watching a documentary by Brian Cox which explained it quite well (can't find the video anymore). Essentially it was about how all species branch from DNA. The fact that there's only DNA, and not other types of life constructs spread around our earth (heck not even 1), would make the beginning of life (abiogenesis) a very rare event. For (ii) it is an obvious rare event because out of the billions of species that ever existed on earth, we're the only ones to have developed technological intelligence. This "characteristic" evolved only once on earth - where life is prolific -, hence by no means a certain development of evolution.
- x5n1 11y ago
  - FTL is not possible. - Technological life exists for a few thousand years. They are a small blip so basically nothing in terms of cosmic timelines. - Even if it sends out probes, those probes generally fall into the gravity wells of the planets they are sent to over the millions of years. - Hence why intelligent life is common, but not often seen. One thing to do, and we should do it fast... is to make self replicating robotic probes that spread throughout the galaxy. I guess it should collect samples of life once it finds it and find ways to seed the universe with it. Or create some sort of Ark of Life to carry DNA from intelligent life forms to other places where they could perhaps be cloned. We should not focus on our own survival, but increasing the chances of intelligent life in general to survive in the universe and find each other. We are probably doomed as a species, but we can do that for the universe.
  - jimmcslim 11y ago
    - Even if it sends out probes, those probes generally fall into the gravity wells of the planets they are sent to over the millions of years. But then wouldn't we have possibly observed these probes? Maybe they have visited our planet, just so long ago such that any evidence of their arrival has decayed...
    - x5n1 11y ago
      Metal decays fast enough, but not only that the Earth's crust moves and most of the planet is water. It's like looking for a small piece of metal that was here say 10 million years ago, is very rusted and probably at the bottom of the ocean. And even if they send probes, it's not as if they or we send a million of them. We send a few, and they are expensive, and they are easily lost.
      - david-given 11y ago
        Why would any self-respecting interstellar civilisation build probes out of metal? It's expensive, heavy, doesn't breed very well, and doesn't last. A true interstellar self-replicating probe is going to look like a fat molecule. Hell, they could be here already; panspermia is still a totally valid theory.
  - daemonfire300 11y ago
    I can only imagine this going horribly wrong. Like when Explorers visited cultures which had been isolated from the rest of the world, not having developed antibodies against a simple flue and getting infected.
  - gus_massa 11y ago
    > One thing to do, and we should do it fast... is to make self replicating robotic probes that spread throughout the galaxy. I guess it should collect samples of life once it finds it and find ways to seed the universe with it. This looks like a bad idea because is a planet has life and the probe seeds it with the life of the other planet, you may kill all the native population. Anyway, the probes we send will have a few bacteria as free riders, so we will seed them with Earth bacterial life anyway. There are some protocols to clean the probes that go to Mars (and other planets), so if find life there it will be Mars' life. (But this is very difficult, I think that bacteria are very sneaky and they probably will win.)
  - pavel_lishin 11y ago
    > - Even if it sends out probes, those probes generally fall into the gravity wells of the planets they are sent to over the millions of years. [citation needed]; a civilization wouldn't just shotgun these things and wave farewell, it would have instrumentation, guidance and engines on board.
    - x5n1 11y ago
      it might have all these things, but if you don't have ftl then they take a very long time to get to their destination. tens of thousands to millions of years. There are a few planets between 4 and 42 light years from here. At 4 light years using a Nuclear pulse propulsion it would take 100 years. At 40 it would take 10x that, so 1,000 years. That's nuclear which requires a immense amount of fuel which probably does not make sense for satellites. Other mechanisms for prop. are much slower. By the time any of these get to their destination, people who built them will be dead and possibly the civilizations which have launched them will have gone extinct.
- jimmcslim 11y ago
  Isn't it technically twice... the Neanderthals? whom possibly would have gone onto further technological advancements had we not out competed them for resources? These observations don't discount the possibility that life is incredibly pervasive throughout the universe, yet on each planet that harbours life it is natural that just one species reaches dominances to make observation about Life, The Universe, and Everything, such as we are making... but are still ultimately prevented from becoming Type III civilisations by physical constraints (i.e. interstellar flight is impossible) and therefore the Great Filter lies before us.
  - sktrdie 11y ago
    Neanderthals are our cousins. Meaning it's essentially a species in the same genus tree (very closely related to us). Characteristics which are "not rare" are found across species in various branches in the tree - think of vision or smell, etc. I do agree however that we might be the first - hell there was a first species that developed vision so why not think we might be the first who have developed tech. intelligence.
    - maxerickson 11y ago
      There is evidence of tool use dating back 2 million+ years. Those species are grouped under genus Homo and would likely have been ancestors of both modern humans and Neanderthals.
- givan 11y ago
  We are so special, the only intelligent species in the galaxy etc reminds me of the sun revolves around earth statement a few hundred years ago, the fact is we don't have the technology to explore even the closest stars, even our own solar system is unexplored, think europa, so making statements about life in the universe based only on one planet is science fiction.
  - ChrisGranger 11y ago
    I agree completely. While we are definitely making progress, it is early days yet and we're still taking baby steps around the playpen of Earth. We haven't even toddled next door to our neighbor, Mars. That said, it means there are lots and lots of exciting missions to look forward to as our technological abilities grow.
- 7952 11y ago
  A good start in answering these question is to look for life in our own solar system. Maybe it is not as rare as we think.
- rndn 11y ago
  I tend to believe that molecular technology and AI are the great filter. Just picture the situation we find ourselves in: We are stuff made from the rules of the pattern generating system that we call our universe. We are figuring out the rules and we are continuously improving our tools to manipulate stuff at an ever lower level. Once we can easily manipulate the building blocks our existence is based on, it opens the door to such a tremendously large number of ways how things can go wrong that the probability of self-destruction comes very close to 1. It would require an extremely high intelligence to deal with all these failure modes, something that an biochemistry-based evolutionary process is highly unlikely to bring forth. The problem is basically that figuring the rules out is much easier than using them safely. The invention of AI makes our tools to manipulate matter vastly more dangerous, for example, intelligent gray goo would be smart enough to not immediately eat away its basis for existence and to plan ahead instead of just executing a simple rule set.
- XorNot 11y ago
  That DNA gains dominance proves very little. It stands to reason that in the primordial soup, once one self-replicating molecular biology came into existence it pretty quickly consumed all the elements any others would need. Moreover, life on Earth proves little about the nature of life anywhere else - for example what type of self-replicating biology might exist in the high pressure environment of a gas giant? We don't know, but all the components are there and there's plenty of energy so why not? The reason Earth-like's are interesting is because we know what we're looking for when we go looking for life on them. They're a sure thing to expend limited resources on.
- robbiep 11y ago
  That the current thinking and evidence on abiogenesis says that this all happened very very early in the earths history would lead me to believe that abiogenesis is probably quite common. The existence of only DNA based life forms, given we now have good evidence that other chemical elements could have become the bases of dna (as opted to g c t and a) would also tend to indicate that it was probably just the 'winner' of that early evolutionary arms race, i.e. What chemical formula can reproduce the fastest under those early conditions
- ChrisGranger 11y ago
  I think it's likely that higher intelligence could evolve more often were it not a "first past the post" race where whichever species gets there first prevents the others from doing so by squeezing them out with regard to the necessary natural resources. Thus, I'm inclined to think that if there are many planets with the required ingredients for life, there could likewise be many examples where intelligent life has arisen, but like on Earth, limited to one advanced species per planet.
- david-given 11y ago
  Well, for (i), we wouldn't necessarily see any of the other life systems if DNA life outcompeted it. Bear in mind that we've only really explored a handful of Earth's ecosystems --- it's known that the microbial biosphere extends way into the lithosphere, for example. I'd be totally unsurprised (although thrilled) to learn of a discovery of an alternate life system there. For (ii), remember that we can't observe any other Earth-like planets in enough detail to know whether there's human-like technological life there or not; all we really know is that we haven't observed any here, and there are plenty of simple explanations why not, one of the most plausible being that transporting human-like creatures from one star system to another in a reasonable time is almost inconceivably hard. In fact, life like ours is so unsuited for living in space that it's probably reasonable to assume that any successful space-based civilisation isn't going to be using life like ours. That assumption leads to some interesting corrolaries: for example, once you're adapted to living way out in the dark, the inner solar system is going to be horribly inhospitable. And you're likely to be quite slow, because everything's going to take a long time. So if such a civilisation existed on the outskirts of Sol system, it would be entirely plausible that they wouldn't come and visit --- coming here is too dangerous, and besides, if we're going to be interesting to talk to we'll be rebuilding ourselves to be like them and be out there soon...
- Udo 11y ago
  The problem is we don't know a lot about the probabilities of abiogenesis. We do know the basic components for life, such as complex hydrocarbons and amino acids, do occur in non-biological nature. The question is how likely they are to combine into something self-replicating. > Essentially it was about how all species branch from DNA That is not correct. Most models consider RNA as a precursor to DNA. Over time, RNA has come to fulfill more narrow intra-cellular roles, but at some point in time it was probably the dominant gene format. By the same token, it's likely that RNA as an information carrier was preceded by other molecules, and very early proto-organisms might not even have had a unified gene carrier system - they might have been just "running systems" that split in two every once in a while. > (ii) we evolved into advanced technological species. This is also doubtful. Humans do combine several fortunate intellectual capabilities, but the components making up our neuronal structure are not unique to us. What's more, we do find advanced capabilities in organisms that developed after we split from a common ancestor, suggesting that the building blocks of general intelligence might arise readily under different circumstances and using different biological implementations (albeit with the caveat that we share a common biochemical machinery, the details of which may or may not make general intelligence more likely).
  - Demiurge 11y ago
    At least one thing I'm optimistic about is that by observing other semi-intelligent species, we can see that social behavior and cooperation is one of the driving forces of intelligence. There are different moralities, cruel to ours, but overall this implies to me a common ability to cooperate and explore, among any evolved civilizations.
    - DanBC 11y ago
      > we can see that social behavior and cooperation is one of the driving forces of intelligence. Most octopuses are solitary animals, yet probably qualify as semi-intelligent.
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- IndianAstronaut 11y ago
  Intelligent life is rare on Earth. Out of tens of millions of species on our planet that exist or have existed, only one is intelligent enough to make a civilization.
- MrBra 11y ago
  Beautiful read on the Fermi Paradox http://waitbutwhy.com/2014/05/fermi-paradox.html http://waitbutwhy.com/2014/05/fermi-paradox.html
idlewords 11y ago
Missions like Kepler are what finally set me against human space flight. Consider the incredible amount of science coming out of projects like this ($600M), New Horizons (750M) or the Planck telescope ($750M), compared to the cost of the international space station (~$100B). For less than the cost of a Shuttle launch, you can get scientific breakthrough after breakthrough, as long as you're not trying to keep primates alive on the thing.
- InclinedPlane 11y ago
  Whoa there. First off, don't use the Shuttle or ISS as the yard stick for "manned spaceflight", they are some of the most expensive programs for the least results in history and are not representative of what can be done with manned spaceflight. Additionally, spaceflight is not just about scientific research. Manned spaceflight is not just about exploration, it's also about colonization. At the end of the day space is just a place, a place where we live, though we have been restricted to a tiny corner of it for most of human history. We can do manned spaceflight cost effectively (orders of magnitude better than the Shuttle, ISS, or Apollo), and as our technology improves our capabilities will only increase while costs fall.
  - idlewords 11y ago
    What is the purpose of colonization? Compared to colonizing Antarctica, for example, or the bottom of the sea? If we can do human spaceflight orders of magnitude cheaper than all attempts to date, that's great news. But I'll believe it when I see it.
    - InclinedPlane 11y ago
      Adventure. Challenge. Spreading the light of human consciousness and civilization off of Earth into the Universe.
    - elektromekatron 11y ago
      People are probably not going to stop shagging.
personlurking 11y ago
Can anyone recommend documentaries or non-fiction shows that explore the what-ifs of finding other earth-like planets? In the previous thread on the discovery of this other Earth, an HNer commented that since the other Earth is older, they could have sent probes over which would have filmed the dinosaurs in HD, and that maybe we could request that data from them. Here's another related thought https://news.ycombinator.com/item?id=9937353 https://news.ycombinator.com/item?id=9937353 Here's another what-if, in the form of a sci-fi film called Another Earth (a personal drama wrapped around the idea of a twin Earth) https://www.youtube.com/watch?v=N8hEwMMDtFY https://www.youtube.com/watch?v=N8hEwMMDtFY
- ChrisGranger 11y ago
  The idea, however unlikely, that there could exist documentary footage of prehistoric Earth is truly mind-blowing when you stop to think about it.
- pavel_lishin 11y ago
  Try https://en.wikipedia.org/wiki/Alien_Planet https://en.wikipedia.org/wiki/Alien_Planet
afro88 11y ago
I think we're approaching another shift in our perception of our surroundings: * The world is flat -> no, round * The sun revolves around the earth -> no, Earth revolves around the sun * Earth is a special unique snowflake -> no, there are 1B "Earths" * Life is an incredibly rare event -> no, life is common throughout the galaxy and universe, just not how we thought it would be?
- vlasev 11y ago
  Just for the record, the "flat Earth" stuff is mostly a myth pushed by latter generations to make earlier generations look and sound dumb.
  - CraneWorm 11y ago
    It's also a thing "a lot" of today's people believe. Possibly to make our generation look and sound dumber. https://en.wikipedia.org/wiki/Modern_flat_Earth_societies https://en.wikipedia.org/wiki/Modern_flat_Earth_societies
- sktrdie 11y ago
  This is such a bad analogy (I think you got it from Neil Tyson or something). What you've done is that you've taken examples of things that we got wrong. However, there's a lot more things we got right back then, that are still right nowadays! So your point that whenever we make predictions, we get them wrong, is totally unfounded.
  - dandrews 11y ago
    GP made no such point.
  - afro88 11y ago
    > (I think you got it from Neil Tyson or something) Lol no, I haven't actually watched any stuff from him, I'm more of a Brian Cox guy. My point wasn't "whenever we make predictions we get them wrong", it was that our accepted model of our universe is always in a state of flux - new revelations come about every so often that totally change this model. Hopefully the next revelation is that there is in fact a lot of life in the universe and we aren't alone.
dharma1 11y ago
I think is incredibly fascinating research , but to me it seems extremely unlikely we as a species will ever leave earth. Maybe we build some sentient AI who will be the next step in intelligence and colonise space but the distances and hostily of space, as well as our total dependence on the rest of the ecosystem on earth makes me think having a plan B for humanity outside earth is a just a folly.
- Sir_Cmpwn 11y ago
  I used to work at SpaceX. I firmly believe that Elon Musk will establish a colony on Mars within my lifetime, and I hope to be there. Everything SpaceX does is working towards that conclusion, and the plan is solid.
  - drcross 11y ago
    Does spaceX take on HB1 visa employees from overseas?
    - Sir_Cmpwn 11y ago
      No. Rockets are more or less intercontinental missiles that are being used for benign purposes, so there are severe restrictions imposed from the government on the employment of foreigners by SpaceX.
  - dharma1 11y ago
    Cool. I think SpaceX is doing incredible work and am positive we will see a manned journey to Mars within our lifetime. But a sustainable colony? Sorry but I don't see it happening. The earth is a paradise, life depends on so many fundamentals which are missing from Mars, as well as an intricate network of trillions of interactions in the ecosystem which took hundreds of millions of years to form. I think we are deluded if we think we can replicate that
    - Sir_Cmpwn 11y ago
      We can replicate that on a small scale. I don't think we'll see Mars terraformed any time soon, but a sustainable colony is possible for sure. Mars is rich in water and we can bring our own plants and animals.
deleted 11y ago
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kctess5 11y ago
"the solar neighborhood within 33 light-years" How tragic, that even if humanity were to receive signal from another intelligent species, we couldn't even close to possibly reach them with current technology. Intelligent species watch each other rise and fall from afar.
- sktrdie 11y ago
  Actually with time dilation the people on the spacecraft could reach several close stars in decades - if we construct fast enough spacecrafts (just needs to be a small fraction of light of speed).
  - pavel_lishin 11y ago
    It would be a pretty great endeavour. We'd have to carry enough fuel to accelerate and decelerate at the end, and enough fuel to push that fuel, etc., etc. (Unless Bussard drives work.) I wonder if anyone's written that story - a relativistic vehicle is headed towards the Earth, launched by a civilization that could get it up to speed but not decelerate, trusting and hoping that our technology is advanced to slow them down on arrival...
nowey 11y ago
theres 500 stars in a radius of 50 light years. hopefully we will find plantes there, a planet 1400 ly away is cool but very distant still if we want to study it in detail
MrBra 11y ago
And now this becomes even more relevant: http://waitbutwhy.com/2014/05/fermi-paradox.html http://waitbutwhy.com/2014/05/fermi-paradox.html
- DanielBMarkham 11y ago
  Let's assume the Great Filter is in front of us. Perhaps biological life eventually creates machine life and then either withers away while machines take over, or fizzles out along the machines it made. Let's also assume that all these other lifeforms, like us, realize that the galaxy is full of livable worlds. There's no FTL, and nobody wants to take over a planet where life has a chance of making it past the filter. This would mean that the only contact would be machine probes who left their civilizations tens of thousands of years into the past. Such probes would be programmed not to initiate contact with worlds with life on them. Instead, collect some data and leave, moving on to other planets and systems. If this is the case, heck, we might have been visited by millions of other intelligent civilizations. The only thing we'd have to show for it would be perhaps the appearance of truly mysterious lights in the sky every decade or so. If you want to stretch your imagination a bit, perhaps a Rendlesham Forest-type incident. I seriously doubt biological life is very interesting to any other civilizations. I doubt they communicate in any way similar to the ways we communicate, and I feel that any direct contact would be so removed and non-reproducible to be useless. There are a lot of hidden assumptions you have to make for Fermi's Paradox to truly be a paradox. (Same goes for my argument, of course.)
  - binarymax 11y ago
    Phew, I'm glad you threw in that last sentence! The largest assumption you made is that biological life evolves the same on every earth-like planet...and that all life from those planets fits our definition of biological. One of the things I love about good sci-fi is that it challenges these assumptions. I'll throw one out there as an example many would know: the crystalline entity in Star Trek TNG.
- elorant 11y ago
  "They're made out of meat" http://www.terrybisson.com/page6/page6.html http://www.terrybisson.com/page6/page6.html
zw123456 11y ago
One thing that I have thought about a few times is not just the time scale but also the technological advancement and where we might sit in that continuum. For example, spread spectrum radio technology that is used for some wireless communications would be virtually impossible for us to detect even a couple of decades ago. So even efforts like SETI may not see anything because you would have to focus in on one of the habitable planets, at the moment in time when they are using the type of radio technologies we know of, in the spectrum we are looking at. It is possible that there are technologically advanced civilizations out there but they moved past radio and are using something more advanced like quantum entanglement modulation or something we don't yet have the technology to decode. If there is a Galactic Internet, it is probably not based on the modulation of electromagnetic radiation which is limited to the speed of light.
- sebastianconcpt 11y ago
  Exactly, electromagnetism is too primitive. Quantum entanglement modulation is more plausible. Or some other phenomenon that could factor out space and time like some hypotetical tech that can interface with Consciousness.
  - strange_quark 11y ago
    Unless we have a huge breakthrough in physics; one in which almost all our previous knowledge is proved wrong, you can't transmit information with quantum entanglement. Doing so violates relativity. Now maybe you can make a wormhole or something, but it seems like EM waves are all we've got.

120 points by 51Cards 11y ago

I really think that the great filter (of the fermi paradox) is behind us. Meaning, some stupefying rare event happened either when (i) life began in the first place, or when (ii) we evolved into advanced technological species. For (i) I remember watching a documentary by Brian Cox which explained it quite well (can't find the video anymore). Essentially it was about how all species branch from DNA. The fact that there's only DNA, and not other types of life constructs spread around our earth (heck not even 1), would make the beginning of life (abiogenesis) a very rare event. For (ii) it is an obvious rare event because out of the billions of species that ever existed on earth, we're the only ones to have developed technological intelligence. This "characteristic" evolved only once on earth - where life is prolific -, hence by no means a certain development of evolution.

x5n1 11y ago
- FTL is not possible. - Technological life exists for a few thousand years. They are a small blip so basically nothing in terms of cosmic timelines. - Even if it sends out probes, those probes generally fall into the gravity wells of the planets they are sent to over the millions of years. - Hence why intelligent life is common, but not often seen. One thing to do, and we should do it fast... is to make self replicating robotic probes that spread throughout the galaxy. I guess it should collect samples of life once it finds it and find ways to seed the universe with it. Or create some sort of Ark of Life to carry DNA from intelligent life forms to other places where they could perhaps be cloned. We should not focus on our own survival, but increasing the chances of intelligent life in general to survive in the universe and find each other. We are probably doomed as a species, but we can do that for the universe.
- jimmcslim 11y ago
  - Even if it sends out probes, those probes generally fall into the gravity wells of the planets they are sent to over the millions of years. But then wouldn't we have possibly observed these probes? Maybe they have visited our planet, just so long ago such that any evidence of their arrival has decayed...
  - x5n1 11y ago
    Metal decays fast enough, but not only that the Earth's crust moves and most of the planet is water. It's like looking for a small piece of metal that was here say 10 million years ago, is very rusted and probably at the bottom of the ocean. And even if they send probes, it's not as if they or we send a million of them. We send a few, and they are expensive, and they are easily lost.
    - david-given 11y ago
      Why would any self-respecting interstellar civilisation build probes out of metal? It's expensive, heavy, doesn't breed very well, and doesn't last. A true interstellar self-replicating probe is going to look like a fat molecule. Hell, they could be here already; panspermia is still a totally valid theory.
- daemonfire300 11y ago
  I can only imagine this going horribly wrong. Like when Explorers visited cultures which had been isolated from the rest of the world, not having developed antibodies against a simple flue and getting infected.
- gus_massa 11y ago
  > One thing to do, and we should do it fast... is to make self replicating robotic probes that spread throughout the galaxy. I guess it should collect samples of life once it finds it and find ways to seed the universe with it. This looks like a bad idea because is a planet has life and the probe seeds it with the life of the other planet, you may kill all the native population. Anyway, the probes we send will have a few bacteria as free riders, so we will seed them with Earth bacterial life anyway. There are some protocols to clean the probes that go to Mars (and other planets), so if find life there it will be Mars' life. (But this is very difficult, I think that bacteria are very sneaky and they probably will win.)
- pavel_lishin 11y ago
  > - Even if it sends out probes, those probes generally fall into the gravity wells of the planets they are sent to over the millions of years. [citation needed]; a civilization wouldn't just shotgun these things and wave farewell, it would have instrumentation, guidance and engines on board.
  - x5n1 11y ago
    it might have all these things, but if you don't have ftl then they take a very long time to get to their destination. tens of thousands to millions of years. There are a few planets between 4 and 42 light years from here. At 4 light years using a Nuclear pulse propulsion it would take 100 years. At 40 it would take 10x that, so 1,000 years. That's nuclear which requires a immense amount of fuel which probably does not make sense for satellites. Other mechanisms for prop. are much slower. By the time any of these get to their destination, people who built them will be dead and possibly the civilizations which have launched them will have gone extinct.
jimmcslim 11y ago
Isn't it technically twice... the Neanderthals? whom possibly would have gone onto further technological advancements had we not out competed them for resources? These observations don't discount the possibility that life is incredibly pervasive throughout the universe, yet on each planet that harbours life it is natural that just one species reaches dominances to make observation about Life, The Universe, and Everything, such as we are making... but are still ultimately prevented from becoming Type III civilisations by physical constraints (i.e. interstellar flight is impossible) and therefore the Great Filter lies before us.
- sktrdie 11y ago
  Neanderthals are our cousins. Meaning it's essentially a species in the same genus tree (very closely related to us). Characteristics which are "not rare" are found across species in various branches in the tree - think of vision or smell, etc. I do agree however that we might be the first - hell there was a first species that developed vision so why not think we might be the first who have developed tech. intelligence.
  - maxerickson 11y ago
    There is evidence of tool use dating back 2 million+ years. Those species are grouped under genus Homo and would likely have been ancestors of both modern humans and Neanderthals.
givan 11y ago
We are so special, the only intelligent species in the galaxy etc reminds me of the sun revolves around earth statement a few hundred years ago, the fact is we don't have the technology to explore even the closest stars, even our own solar system is unexplored, think europa, so making statements about life in the universe based only on one planet is science fiction.
- ChrisGranger 11y ago
  I agree completely. While we are definitely making progress, it is early days yet and we're still taking baby steps around the playpen of Earth. We haven't even toddled next door to our neighbor, Mars. That said, it means there are lots and lots of exciting missions to look forward to as our technological abilities grow.
7952 11y ago
A good start in answering these question is to look for life in our own solar system. Maybe it is not as rare as we think.
rndn 11y ago
I tend to believe that molecular technology and AI are the great filter. Just picture the situation we find ourselves in: We are stuff made from the rules of the pattern generating system that we call our universe. We are figuring out the rules and we are continuously improving our tools to manipulate stuff at an ever lower level. Once we can easily manipulate the building blocks our existence is based on, it opens the door to such a tremendously large number of ways how things can go wrong that the probability of self-destruction comes very close to 1. It would require an extremely high intelligence to deal with all these failure modes, something that an biochemistry-based evolutionary process is highly unlikely to bring forth. The problem is basically that figuring the rules out is much easier than using them safely. The invention of AI makes our tools to manipulate matter vastly more dangerous, for example, intelligent gray goo would be smart enough to not immediately eat away its basis for existence and to plan ahead instead of just executing a simple rule set.
XorNot 11y ago
That DNA gains dominance proves very little. It stands to reason that in the primordial soup, once one self-replicating molecular biology came into existence it pretty quickly consumed all the elements any others would need. Moreover, life on Earth proves little about the nature of life anywhere else - for example what type of self-replicating biology might exist in the high pressure environment of a gas giant? We don't know, but all the components are there and there's plenty of energy so why not? The reason Earth-like's are interesting is because we know what we're looking for when we go looking for life on them. They're a sure thing to expend limited resources on.
robbiep 11y ago
That the current thinking and evidence on abiogenesis says that this all happened very very early in the earths history would lead me to believe that abiogenesis is probably quite common. The existence of only DNA based life forms, given we now have good evidence that other chemical elements could have become the bases of dna (as opted to g c t and a) would also tend to indicate that it was probably just the 'winner' of that early evolutionary arms race, i.e. What chemical formula can reproduce the fastest under those early conditions
ChrisGranger 11y ago
I think it's likely that higher intelligence could evolve more often were it not a "first past the post" race where whichever species gets there first prevents the others from doing so by squeezing them out with regard to the necessary natural resources. Thus, I'm inclined to think that if there are many planets with the required ingredients for life, there could likewise be many examples where intelligent life has arisen, but like on Earth, limited to one advanced species per planet.
david-given 11y ago
Well, for (i), we wouldn't necessarily see any of the other life systems if DNA life outcompeted it. Bear in mind that we've only really explored a handful of Earth's ecosystems --- it's known that the microbial biosphere extends way into the lithosphere, for example. I'd be totally unsurprised (although thrilled) to learn of a discovery of an alternate life system there. For (ii), remember that we can't observe any other Earth-like planets in enough detail to know whether there's human-like technological life there or not; all we really know is that we haven't observed any here, and there are plenty of simple explanations why not, one of the most plausible being that transporting human-like creatures from one star system to another in a reasonable time is almost inconceivably hard. In fact, life like ours is so unsuited for living in space that it's probably reasonable to assume that any successful space-based civilisation isn't going to be using life like ours. That assumption leads to some interesting corrolaries: for example, once you're adapted to living way out in the dark, the inner solar system is going to be horribly inhospitable. And you're likely to be quite slow, because everything's going to take a long time. So if such a civilisation existed on the outskirts of Sol system, it would be entirely plausible that they wouldn't come and visit --- coming here is too dangerous, and besides, if we're going to be interesting to talk to we'll be rebuilding ourselves to be like them and be out there soon...
Udo 11y ago
The problem is we don't know a lot about the probabilities of abiogenesis. We do know the basic components for life, such as complex hydrocarbons and amino acids, do occur in non-biological nature. The question is how likely they are to combine into something self-replicating. > Essentially it was about how all species branch from DNA That is not correct. Most models consider RNA as a precursor to DNA. Over time, RNA has come to fulfill more narrow intra-cellular roles, but at some point in time it was probably the dominant gene format. By the same token, it's likely that RNA as an information carrier was preceded by other molecules, and very early proto-organisms might not even have had a unified gene carrier system - they might have been just "running systems" that split in two every once in a while. > (ii) we evolved into advanced technological species. This is also doubtful. Humans do combine several fortunate intellectual capabilities, but the components making up our neuronal structure are not unique to us. What's more, we do find advanced capabilities in organisms that developed after we split from a common ancestor, suggesting that the building blocks of general intelligence might arise readily under different circumstances and using different biological implementations (albeit with the caveat that we share a common biochemical machinery, the details of which may or may not make general intelligence more likely).
- Demiurge 11y ago
  At least one thing I'm optimistic about is that by observing other semi-intelligent species, we can see that social behavior and cooperation is one of the driving forces of intelligence. There are different moralities, cruel to ours, but overall this implies to me a common ability to cooperate and explore, among any evolved civilizations.
  - DanBC 11y ago
    > we can see that social behavior and cooperation is one of the driving forces of intelligence. Most octopuses are solitary animals, yet probably qualify as semi-intelligent.
- deleted 11y ago
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IndianAstronaut 11y ago
Intelligent life is rare on Earth. Out of tens of millions of species on our planet that exist or have existed, only one is intelligent enough to make a civilization.
MrBra 11y ago
Beautiful read on the Fermi Paradox http://waitbutwhy.com/2014/05/fermi-paradox.html http://waitbutwhy.com/2014/05/fermi-paradox.html

idlewords 11y ago

Missions like Kepler are what finally set me against human space flight. Consider the incredible amount of science coming out of projects like this ($600M), New Horizons (750M) or the Planck telescope ($750M), compared to the cost of the international space station (~$100B). For less than the cost of a Shuttle launch, you can get scientific breakthrough after breakthrough, as long as you're not trying to keep primates alive on the thing.

InclinedPlane 11y ago
Whoa there. First off, don't use the Shuttle or ISS as the yard stick for "manned spaceflight", they are some of the most expensive programs for the least results in history and are not representative of what can be done with manned spaceflight. Additionally, spaceflight is not just about scientific research. Manned spaceflight is not just about exploration, it's also about colonization. At the end of the day space is just a place, a place where we live, though we have been restricted to a tiny corner of it for most of human history. We can do manned spaceflight cost effectively (orders of magnitude better than the Shuttle, ISS, or Apollo), and as our technology improves our capabilities will only increase while costs fall.
- idlewords 11y ago
  What is the purpose of colonization? Compared to colonizing Antarctica, for example, or the bottom of the sea? If we can do human spaceflight orders of magnitude cheaper than all attempts to date, that's great news. But I'll believe it when I see it.
  - InclinedPlane 11y ago
    Adventure. Challenge. Spreading the light of human consciousness and civilization off of Earth into the Universe.
  - elektromekatron 11y ago
    People are probably not going to stop shagging.

personlurking 11y ago

Can anyone recommend documentaries or non-fiction shows that explore the what-ifs of finding other earth-like planets? In the previous thread on the discovery of this other Earth, an HNer commented that since the other Earth is older, they could have sent probes over which would have filmed the dinosaurs in HD, and that maybe we could request that data from them. Here's another related thought https://news.ycombinator.com/item?id=9937353 https://news.ycombinator.com/item?id=9937353 Here's another what-if, in the form of a sci-fi film called Another Earth (a personal drama wrapped around the idea of a twin Earth) https://www.youtube.com/watch?v=N8hEwMMDtFY https://www.youtube.com/watch?v=N8hEwMMDtFY

ChrisGranger 11y ago
The idea, however unlikely, that there could exist documentary footage of prehistoric Earth is truly mind-blowing when you stop to think about it.
pavel_lishin 11y ago
Try https://en.wikipedia.org/wiki/Alien_Planet https://en.wikipedia.org/wiki/Alien_Planet

afro88 11y ago

I think we're approaching another shift in our perception of our surroundings: * The world is flat -> no, round * The sun revolves around the earth -> no, Earth revolves around the sun * Earth is a special unique snowflake -> no, there are 1B "Earths" * Life is an incredibly rare event -> no, life is common throughout the galaxy and universe, just not how we thought it would be?

vlasev 11y ago
Just for the record, the "flat Earth" stuff is mostly a myth pushed by latter generations to make earlier generations look and sound dumb.
- CraneWorm 11y ago
  It's also a thing "a lot" of today's people believe. Possibly to make our generation look and sound dumber. https://en.wikipedia.org/wiki/Modern_flat_Earth_societies https://en.wikipedia.org/wiki/Modern_flat_Earth_societies
sktrdie 11y ago
This is such a bad analogy (I think you got it from Neil Tyson or something). What you've done is that you've taken examples of things that we got wrong. However, there's a lot more things we got right back then, that are still right nowadays! So your point that whenever we make predictions, we get them wrong, is totally unfounded.
- dandrews 11y ago
  GP made no such point.
- afro88 11y ago
  > (I think you got it from Neil Tyson or something) Lol no, I haven't actually watched any stuff from him, I'm more of a Brian Cox guy. My point wasn't "whenever we make predictions we get them wrong", it was that our accepted model of our universe is always in a state of flux - new revelations come about every so often that totally change this model. Hopefully the next revelation is that there is in fact a lot of life in the universe and we aren't alone.

dharma1 11y ago

I think is incredibly fascinating research , but to me it seems extremely unlikely we as a species will ever leave earth. Maybe we build some sentient AI who will be the next step in intelligence and colonise space but the distances and hostily of space, as well as our total dependence on the rest of the ecosystem on earth makes me think having a plan B for humanity outside earth is a just a folly.

Sir_Cmpwn 11y ago
I used to work at SpaceX. I firmly believe that Elon Musk will establish a colony on Mars within my lifetime, and I hope to be there. Everything SpaceX does is working towards that conclusion, and the plan is solid.
- drcross 11y ago
  Does spaceX take on HB1 visa employees from overseas?
  - Sir_Cmpwn 11y ago
    No. Rockets are more or less intercontinental missiles that are being used for benign purposes, so there are severe restrictions imposed from the government on the employment of foreigners by SpaceX.
- dharma1 11y ago
  Cool. I think SpaceX is doing incredible work and am positive we will see a manned journey to Mars within our lifetime. But a sustainable colony? Sorry but I don't see it happening. The earth is a paradise, life depends on so many fundamentals which are missing from Mars, as well as an intricate network of trillions of interactions in the ecosystem which took hundreds of millions of years to form. I think we are deluded if we think we can replicate that
  - Sir_Cmpwn 11y ago
    We can replicate that on a small scale. I don't think we'll see Mars terraformed any time soon, but a sustainable colony is possible for sure. Mars is rich in water and we can bring our own plants and animals.

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kctess5 11y ago

"the solar neighborhood within 33 light-years" How tragic, that even if humanity were to receive signal from another intelligent species, we couldn't even close to possibly reach them with current technology. Intelligent species watch each other rise and fall from afar.

sktrdie 11y ago
Actually with time dilation the people on the spacecraft could reach several close stars in decades - if we construct fast enough spacecrafts (just needs to be a small fraction of light of speed).
- pavel_lishin 11y ago
  It would be a pretty great endeavour. We'd have to carry enough fuel to accelerate and decelerate at the end, and enough fuel to push that fuel, etc., etc. (Unless Bussard drives work.) I wonder if anyone's written that story - a relativistic vehicle is headed towards the Earth, launched by a civilization that could get it up to speed but not decelerate, trusting and hoping that our technology is advanced to slow them down on arrival...

nowey 11y ago

theres 500 stars in a radius of 50 light years. hopefully we will find plantes there, a planet 1400 ly away is cool but very distant still if we want to study it in detail

MrBra 11y ago

And now this becomes even more relevant: http://waitbutwhy.com/2014/05/fermi-paradox.html http://waitbutwhy.com/2014/05/fermi-paradox.html

DanielBMarkham 11y ago
Let's assume the Great Filter is in front of us. Perhaps biological life eventually creates machine life and then either withers away while machines take over, or fizzles out along the machines it made. Let's also assume that all these other lifeforms, like us, realize that the galaxy is full of livable worlds. There's no FTL, and nobody wants to take over a planet where life has a chance of making it past the filter. This would mean that the only contact would be machine probes who left their civilizations tens of thousands of years into the past. Such probes would be programmed not to initiate contact with worlds with life on them. Instead, collect some data and leave, moving on to other planets and systems. If this is the case, heck, we might have been visited by millions of other intelligent civilizations. The only thing we'd have to show for it would be perhaps the appearance of truly mysterious lights in the sky every decade or so. If you want to stretch your imagination a bit, perhaps a Rendlesham Forest-type incident. I seriously doubt biological life is very interesting to any other civilizations. I doubt they communicate in any way similar to the ways we communicate, and I feel that any direct contact would be so removed and non-reproducible to be useless. There are a lot of hidden assumptions you have to make for Fermi's Paradox to truly be a paradox. (Same goes for my argument, of course.)
- binarymax 11y ago
  Phew, I'm glad you threw in that last sentence! The largest assumption you made is that biological life evolves the same on every earth-like planet...and that all life from those planets fits our definition of biological. One of the things I love about good sci-fi is that it challenges these assumptions. I'll throw one out there as an example many would know: the crystalline entity in Star Trek TNG.
elorant 11y ago
"They're made out of meat" http://www.terrybisson.com/page6/page6.html http://www.terrybisson.com/page6/page6.html

zw123456 11y ago

One thing that I have thought about a few times is not just the time scale but also the technological advancement and where we might sit in that continuum. For example, spread spectrum radio technology that is used for some wireless communications would be virtually impossible for us to detect even a couple of decades ago. So even efforts like SETI may not see anything because you would have to focus in on one of the habitable planets, at the moment in time when they are using the type of radio technologies we know of, in the spectrum we are looking at. It is possible that there are technologically advanced civilizations out there but they moved past radio and are using something more advanced like quantum entanglement modulation or something we don't yet have the technology to decode. If there is a Galactic Internet, it is probably not based on the modulation of electromagnetic radiation which is limited to the speed of light.

sebastianconcpt 11y ago
Exactly, electromagnetism is too primitive. Quantum entanglement modulation is more plausible. Or some other phenomenon that could factor out space and time like some hypotetical tech that can interface with Consciousness.
- strange_quark 11y ago
  Unless we have a huge breakthrough in physics; one in which almost all our previous knowledge is proved wrong, you can't transmit information with quantum entanglement. Doing so violates relativity. Now maybe you can make a wormhole or something, but it seems like EM waves are all we've got.