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Is Extraterrestrial Life More Whimsical Than Plausible?

coondoggie writes "Princeton University researchers are throwing some cold water on the hot notion that astrobiologists and other scientists expect to one day find life on other planets. Recent discoveries of planets similar to Earth in size and proximity to the planets' respective suns have sparked scientific and public excitement about the possibility of also finding Earth-like life on those worlds, but the expectation that life — from bacteria to sentient beings — has or will develop on other planets as on Earth might be based more on optimism than scientific evidence."

16 of 344 comments (clear)

  1. It's not Optimism, by CanHasDIY · · Score: 4, Insightful

    It's statistical probability, you Philistine!

    --
    An enigma, wrapped in a riddle, shrouded in bacon and cheese
    1. Re:It's not Optimism, by CanHasDIY · · Score: 4, Insightful

      It's statistical probability, you Philistine!

      "The researchers used a Bayesian analysis—which weighs how much of a scientific conclusion stems from actual data and how much comes from the prior assumptions of the scientist—to determine the probability of extraterrestrial life once the influence of these presumptions is minimized." Source

      ...possibility of also finding Earth-like life on those worlds

      Whoever said extraterrestrial life had to be "Earth-like?"

      Thus is the fallacy of the analysis.

      --
      An enigma, wrapped in a riddle, shrouded in bacon and cheese
    2. Re:It's not Optimism, by Anonymous Coward · · Score: 5, Insightful

      It's statistical probability, you Philistine!

      "The researchers used a Bayesian analysis—which weighs how much of a scientific conclusion stems from actual data and how much comes from the prior assumptions of the scientist—to determine the probability of extraterrestrial life once the influence of these presumptions is minimized."
      Source

      Which amounts to, "my filter hasn't found any papers on extra-terrestrial life we've found yet, so clearly no evidence of extra-terrestrial life exists." I don't need a Bayesian filter to figure that one out, and it's actually pretty stupid to use one. We already know that we haven't found any life outside the Earth.

      That said, the existence of life on Earth is all the evidence you need for life elsewhere. The chance of life arising is bigger than zero, and the amount of planets is large enough that for anything with probability not zero, it's going to happen more than once. The only valid question is just how full of life is the universe? Is it mostly lifeless or chock-full of it?

    3. Re:It's not Optimism, by networkBoy · · Score: 4, Insightful

      If you are willing to stipulate that God exists this actually makes for an awesome thought experiment.
      Would God, being omnipotent and omnipresent want multiple worlds of beings?
      What if he was curious* as to silicon based life, that would appear to be incompatible with a world configured for carbon life, so he would need to spin up another world.
      What if God wanted a world of fire to play with creatures for whom consciousness existed in the flickering of flames?
      There appears to be no reason why he wouldn't want other worlds, of course there is also no reason why he would either.

      Imagine the possibilities, something akin to the final scene of MiB where the galaxy is really in a marble being played with, maybe there are other marbles?

      Whether or not you choose to believe is a decision only you can make, doesn't mean you can't have fun with various viewpoints. That said, I think the God talk on /. is the new troll. Guaranteed to get a response every time ;)
      -nB

      * Of course being omnipotent means there is no curiosity, as God already knows everything... Thus why bother with the first world (assuming that's us) in the first place?

      --
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    4. Re:It's not Optimism, by 0111+1110 · · Score: 4, Insightful

      Garbage in garbage out. There is currently insufficient data upon which to base any sort of 'estimate'. There is currently no way to know how many earth-like worlds there are in the galaxy. It certainly seems likely that the number of earth-like worlds in any galaxy would be a non-zero number, but currently all we can do is speculate wildly. So far we haven't found even one other earth-like world. All we have found is that there seem to be a large variety of planets orbiting many, perhaps most, stars at a large variety of orbital distances, including some in the goldilocks zones. Now we have some evidence from which we can conclude that planets are relatively common, but we simply cannot say how common earth-like water planets are.

      --
      Quite an experience to live in fear, isn't it? That's what it is to be a slave.
  2. They found intelligent life on Earth? by Anonymous Coward · · Score: 4, Insightful

    In all seriousness, we haven't even got a foot on the next planet over. I think we can afford to not bicker and argue over the prospects for life elsewhere for a bit. Give science a chance to discover what it will.

  3. Where is my flying car? by PeanutButterBreath · · Score: 4, Insightful

    I think we are at a point where most adults have grown up their entire lives with the assumption that certain great discoveries and advancements will be made in their lifetime. Moon bases. Mars missions. Evidence (at least) of extra-terrestrial life. As these folks (I am one of them) hit the downward slope of their life expectancy (which itself hasn't seen the expected advancements), I expect much more wild speculation, straw-grasping and fallacious conclusions about what "must" exist.

    If the universe is so immense that it is unlikely that extra-terrestrial life doesn't exist, then it is immense enough that we will probably never find it. Then there is the whole issue of whether that life evolved and died a billion years in the past.

    Meanwhile, there are plenty of real problems to be solved and discoveries to be made here on Earth, if anyone is still interested.

    Not saying don't look. Just saying be realistic.

  4. observable data set - 1 planet with life by RichMan · · Score: 4, Insightful

    The science is severly limited by the fact our observable data set of worlds with life consists of a single sample.

    It is vary hard to do science with a single sample.

  5. Re:observable data set - 1 planet with life by Hentes · · Score: 4, Insightful

    This. We can't even confirm or deny the existence of life on Venus or Mars.

  6. Actually it's based on statistics by msobkow · · Score: 4, Insightful

    The idea of finding life on other planets is actually based on statistics. There are literally billions of Earth-like planets in the universe. The chances are that conditions on at least some of those planets has given rise to life.

    There is also a very good statistical chance that there are non-carbon life-forms on other planets.

    So unless you've got a "God created the Earth" mentality, there being life on other planets is a foregone conclusion.

    Does that mean we'll encounter life from other planets? Perhaps not. That depends on whether any forms of FTL ever prove feasible, beyond which there's the roll of the dice of the rarity of planets with life. The odds are you'd have visit and explore a fair number of dead worlds before you'd encounter one with life.

    Only those who think we are "created in God's image" would stick their heads in the sand and claim otherwise. God has no image, and it's form is the universe itself. To think we look anything like the universe is ludicrous!

    --
    I do not fail; I succeed at finding out what does not work.
    1. Re:Actually it's based on statistics by Rostin · · Score: 4, Insightful

      The idea of finding life on other planets is actually based on statistics. There are literally billions of Earth-like planets in the universe. The chances are that conditions on at least some of those planets has given rise to life.

      And what, if I may be so crass as to inquire, do you base that assessment on? The fact that "billions" is a large-seeming number? What if the probability of life (as we know it) forming on an earth-like planet is 1:10^12? The point of the article is that we simply don't know what that probability is, so arguments like the one you are making here are based on fantasy rather than evidence.

      There is also a very good statistical chance that there are non-carbon life-forms on other planets.

      Again: How do you know? Before, you were making a statistical argument from a sample size of one, which is bad. But now, since we know of zero planets that host non-carbon-based life, you are making an argument based on literally nothing but maybe old Star Trek episodes.

  7. Re:Paywall ... by siddesu · · Score: 5, Insightful

    And having read the link, I can only say that my own statistical analysis shows with a high degree of confidence that every earth-centric or earth-is-unique argument made so far has been proven wrong. Therefore, expectations that this particular view will endure are probably based on optimism rather than evidence.

  8. Nearly a certainty by Sycraft-fu · · Score: 4, Insightful

    Neil DeGrasse Tyson gives a good talk on this, as usual with things related to astrophysics. He points out that the elements we find in our bodies are the same elements you find in the universe, and in the same order (hydrogen is the most common in the universe, and is the most common in us) and that you can trace the atoms in us to the crucible that formed stars. We are, literally, stardust. Well that is almost certainly not a coincidence. We are made of what we are made because the universe is made of what it is made. Same shit with carbon being our building block: Carbon is THE building block, you can make more molecules with it than with all other elements combined.

    So looking at all that, we look pretty damn typical, pretty damn common. Thus when you have galaxies with hundreds of billions of stars, and 100-200 billion (observed) galaxies in the universe it becomes a near statistical certainty that such a thing would happen elsewhere. We aren't some special collection of elements that you are highly unlikely to see, we are precisely what you'd expect based on cosmic observation.

    1. Re:Nearly a certainty by Bill,+Shooter+of+Bul · · Score: 4, Insightful

      But no one knows what the odds are of a getting all the conditions right for life to start.

      If you assume that life must be everywhere, then you have to assume that those odds are pretty good.
      If you assume that life isn't everywhere, then you have to assume that the odds are not very good.

      So, In the end that little nugget of information doesn't really help at all. Its just more information that will be viewed through the colored lense of the beholder. In a small kind-of-sort of way, that's what this study is saying.The probability of life existing is determined in a large part by how much researchers assume it to be, rather than on any hard scientific method.

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      Well.. maybe. Or Maybe not. But Definitely not sort of.
  9. utter nonsense by khipu · · Score: 5, Insightful

    There is no support either for or against the existence of life on other planets. Bayesian analysis doesn't transform that lack of knowledge into evidence against life. After Bayesian analysis, people still don't have any facts.

    However, I'd say things certainly look better now than they did a few decades ago, given that we have discovered both vast amounts of organic molecules in space, as well as lots of planets in the Goldilocks zone.

  10. Re:Paywall ... by hairyfeet · · Score: 4, Insightful

    I think Neil DeGrasse Tyson explained it simply, I paraphrase "We are made out of the most common elements in the universe. Only the height of arrogance would say that life couldn't happen anywhere but here". Of course the bigger problem would be that if you actually DID have a race that was able to master space and time what would you talk about? Check out his thoughts here, quite interesting.

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