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These factors are what I call the “trappings of life”. It is a completely open question (and I mean completely) how likely life is to arise spontaneously when t

These factors are what I call the “trappings of life”. It is a completely open question (and I mean completely) how likely life is to arise spontaneously when these factors are present. One single instance of life elsewhere or successful abiogenesis in the lab would change that, but we have neither.

malfist 3y ago
We've barely started looking. It's like picking up one piece of hay, not finding a needle and declaring there's no needle in the haystack.
- superposeur 3y ago
  No is declaring that there is no needle in the haystack. Please actually read my post.
  - stouset 3y ago
    “I just want to be clear that we’ve definitely not actually found life. We’ve found likely precursors everywhere, habitable bodies everywhere, have plausible theories on how to go from precursors to bootstrapping, and see life in every corner of the planet we have explored. But just to be clear we haven’t actually found life anywhere else yet.” Yeah, we know. So what then was the point of your post?
    - superposeur 3y ago
      Well, perhaps you know that none of the recent findings are evidence of life, but in my conversations with others I have perceived a great deal of confusion on this point, even among scientifically literate colleagues. Also, the fact that we have zero understanding of the probability of abiogenesis is, in my experience, a greatly under-appreciated fact. I speculate that the way findings are reported contributes to this confusion. Also, at risk of incurring a flame, I'll gently point out that you are folding into this confusion and reinforcing it with your language: "likely precursors everywhere, habitable bodies" ... we absolutely do not know that these conditions are "likely" precursors, which is a statement about a probability we know nothing about and as for "habitable" we do not actually know anything about whether or not a body is habitable in the sense of likely to spontaneously form life.
  - yieldcrv 3y ago
    absence of evidence is not evidence of absence sorry your life has created this crusade of rhetorically reminding people about the absence is evidence
    - superposeur 3y ago
      Not in general, just on this particular point. Because, in my opinion, we as a scientific community are currently flush with the (very cool) unexpected discovery of so many exoplanets and it is somewhat distorting our collective thinking about life and its origins.
      - creer 3y ago
        We SHOULD (be flush and distorted). We can be realistic AND enthusiastic about it. Some technically challenging work was done and achieved results FAR FAR beyond expectations. That is a result worthy of changing outlook. Before, the outlook was on statistical grounds (the universe is so vast that there has to be). Now this outlook has been justified a billion billion times over. It's certainly time to be far more ambitious and inverse the presumptions that we had before. I.e. before, "there had to be - some, somewhere" and now, "there is most likely all over the place".
      - idlewords 3y ago
        You can make the less charged argument that expanding the search for life has in every case so far led to extremely interesting scientific discoveries. So as a pragmatic strategy, it has legs regardless of where you stand on the question of life origins.
    - hesk 3y ago
      Provided you're actively and systematically looking for evidence, then absence of evidence is evidence of absence.
      - malfist 3y ago
        But we've not even started doing that yet. None of the mars rovers have landed anywhere close to where we think is must likely to currently harbor life due to fear of contamination. We've just now learned how to analyze atmospheres of exoplants. 5 years ago, we couldn't see exoplanets smaller than jupiter. A decade ago, we couldn't see exoplanets at all.
  - deleted 3y ago
    [deleted]
vlovich123 3y ago
I agree it’s an open question, but I think it’s highly likely with lots of circumstantial evidence that life is an evolutionary emergent phenomenon where inorganic material reactions create life. We already know that’s the case in highly controlled environments. We don’t yet have confidence about the exact mechanism on Earth but based on those experiments it’s likely (& generally currently accepted as the most likely mechanism AFAIK) that the boundary layer of volcanoes (probably underwater) + some crucial initial elements being available causes life to form “spontaneously”. Given the elements required and their overall availability in the universe, it’s also highly likely these conditions reproduce quite readily & life is generally quite abundant. Similarly, significant levels of intelligence within animals seems like quite a common occurrence as well (great and lesser apes, elephants, octopuses, dolphins, wolves etc). Whether or not intelligence + physiological evolution + social evolution to take advantage of that intelligence to build things cooperatively is a huge unknown of course although I think it’s inevitable. On the other hand, how long life sticks around on a planet once it forms is an open question - it’s not clear if a life ecosystem that’s stable for billions of years is likely and I suspect there’s probably a small amount of filtering that happens where planets become inhospitable rather “quickly” and can’t support life for multiple billions of years (e.g. there were probably several events in our history where it could have collapsed). Our type of society is probably much much rarer because you need access to mineral and energy deposits to go through each technological phase. For example, because of all the mining we’ve done, if humanity were to disappear it’s highly likely the Earth would not sustain another technological society because all the “easy to get to” deposits of crucial metals & things like oil are gone and there’s no way to bootstrap a technological society (it’s possible other kinds of resources could be developed to build other kinds of technology so who knows). I think based on our existing body of knowledge, life is likely extremely plentiful throughout the universe at one point in time or another. Some form of intelligent life is highly likely wherever we find any life that manages to stick around through bilions of years. A highly technological adept species of life though is highly likely an extreme rarity and a planet gets one shot at developing it. Whether any manages to escape their home planet remains an open question that likely only we will manage to answer over the next thousands of years if we make it that far.
- ghaff 3y ago
idlewords 3y ago
The other part of the open question is how easily life is able to spread across worlds. This is why it's so vital to go look at Mars without contaminating the search. If life spreads easily (whether within the solar system or more widely), then we'll likely find traces of life there that look a lot like our own. If life arises easily, but doesn't spread easily, we may find traces of very un-earthlike biochemistry. And if life is rare, we'd expect to find nothing. Any of the three results would have huge implications. And then rinse and repeat on Enceladus, Ganymede, Europa, and so on. And find a way to look at exoplanet atmospheres and chase stuff that comes in from outside the solar system. Even negative results will add enormously to our understanding.
- addicted 3y ago
  At this point isn’t Mars already contaminated?
  - idlewords 3y ago
    No, almost certainly not. There are individual living microbes and spores on the various landers, but unlike the microbiome that would travel with a human mission, they're not viable and have no mechanism to get to somewhere where they'd be viable.
    - RajT88 3y ago
      I mean, you say that, but also this story was a thing that happened: https://www.cnet.com/science/sea-plankton-found-on-the-outer-surface-of-the-iss/ https://www.cnet.com/science/sea-plankton-found-on-the-outer...
      - vel0city 3y ago
        The leading theory is air currents from the planet slowly contaminated the station over the decades, not contamination before launch. It's also then still pretty protected by radiation still being so close to Eath. Our probes go through pretty tight clean room packaging, shed almost all their outside layers before leaving Earth orbit while still being very toasty, and then get blasted by intense radiation for months and are finally separated by some pretty massive distances on the planet.
creer 3y ago
idlewords was specifically mentioning that we have (found life elsewhere). It was pretty clear to people that there would be no life 750 metres inside the earth crust below another 700m of ocean: too hot, no light, pressure, bla, bla. - And plenty was found. Of course it's an easy counter "Still Earth, haha! Doesn't count". So yes, it's back to the point that whenever we have developped tech to go look, we have found "whatever the tech could find". Except - for now - TV serials radio waves. That's true. And bacteria on Mars. Yes it's a glib way to put it but it's not an unfair answer to that criticism.
NotSammyHagar 3y ago
I went to a biology/astronomy talk where there was a researcher working on the sequence of chemical changes on the early earth without much water or atmosphere would need to create dna base pairs. It was stunning because they basically had a sequence of things and geological discoveries point toward the precursor chemicals being available. It's not that dna was just there. This is not "life arising spontaneously". This is chemicals in an environment where they eventually build dna base pairs. Then after millions of years, perhaps you get microbes and go from there. Meanwhile we are getting water on earth from comets crashing down.
- superposeur 3y ago
  The “eventually build dna base pairs” (that continue self replicating) is the uncertain and possibly ludicrously improbable step. See for instance https://www.nature.com/articles/s41598-020-58060-0 https://www.nature.com/articles/s41598-020-58060-0 which argues for a probability per exoplanet small enough that it hasn’t happened a second time in the observable universe. On the other hand, one of the self-organizing proposals cited elsewhere in this thread may turn out to be correct and the probability may be much higher. The point is that, while there are some cool ideas on the table, everything hinges on the particular value of this probability (not just a qualitative story of how life might have arisen) and we don’t know what it is. Still relevant: https://blogs.scientificamerican.com/cross-check/pssst-dont-tell-the-creationists-but-scientists-dont-have-a-clue-how-life-began/ https://blogs.scientificamerican.com/cross-check/pssst-dont-...
  - NotSammyHagar 3y ago
    Sorry, I didn't see your posting before. The person speaking at the astronomy on tap presentation made it seem much more likely, basically given expected conditions on pre-biotic earth, very likely in a million year timeframe. I'm a software engineer so I don't readily admit I don't know what I'm talking about. Are you in the field and can maybe elaborate on your skepticism? This fellow was pretty certain they've worked out several likely possible paths. This was last year.
    - 3y ago

malfist 3y ago

We've barely started looking. It's like picking up one piece of hay, not finding a needle and declaring there's no needle in the haystack.

superposeur 3y ago
No is declaring that there is no needle in the haystack. Please actually read my post.
- stouset 3y ago
  “I just want to be clear that we’ve definitely not actually found life. We’ve found likely precursors everywhere, habitable bodies everywhere, have plausible theories on how to go from precursors to bootstrapping, and see life in every corner of the planet we have explored. But just to be clear we haven’t actually found life anywhere else yet.” Yeah, we know. So what then was the point of your post?
  - superposeur 3y ago
    Well, perhaps you know that none of the recent findings are evidence of life, but in my conversations with others I have perceived a great deal of confusion on this point, even among scientifically literate colleagues. Also, the fact that we have zero understanding of the probability of abiogenesis is, in my experience, a greatly under-appreciated fact. I speculate that the way findings are reported contributes to this confusion. Also, at risk of incurring a flame, I'll gently point out that you are folding into this confusion and reinforcing it with your language: "likely precursors everywhere, habitable bodies" ... we absolutely do not know that these conditions are "likely" precursors, which is a statement about a probability we know nothing about and as for "habitable" we do not actually know anything about whether or not a body is habitable in the sense of likely to spontaneously form life.
- yieldcrv 3y ago
  absence of evidence is not evidence of absence sorry your life has created this crusade of rhetorically reminding people about the absence is evidence
  - superposeur 3y ago
    Not in general, just on this particular point. Because, in my opinion, we as a scientific community are currently flush with the (very cool) unexpected discovery of so many exoplanets and it is somewhat distorting our collective thinking about life and its origins.
    - creer 3y ago
      We SHOULD (be flush and distorted). We can be realistic AND enthusiastic about it. Some technically challenging work was done and achieved results FAR FAR beyond expectations. That is a result worthy of changing outlook. Before, the outlook was on statistical grounds (the universe is so vast that there has to be). Now this outlook has been justified a billion billion times over. It's certainly time to be far more ambitious and inverse the presumptions that we had before. I.e. before, "there had to be - some, somewhere" and now, "there is most likely all over the place".
    - idlewords 3y ago
      You can make the less charged argument that expanding the search for life has in every case so far led to extremely interesting scientific discoveries. So as a pragmatic strategy, it has legs regardless of where you stand on the question of life origins.
  - hesk 3y ago
    Provided you're actively and systematically looking for evidence, then absence of evidence is evidence of absence.
    - malfist 3y ago
      But we've not even started doing that yet. None of the mars rovers have landed anywhere close to where we think is must likely to currently harbor life due to fear of contamination. We've just now learned how to analyze atmospheres of exoplants. 5 years ago, we couldn't see exoplanets smaller than jupiter. A decade ago, we couldn't see exoplanets at all.
- deleted 3y ago
  [deleted]

vlovich123 3y ago

I agree it’s an open question, but I think it’s highly likely with lots of circumstantial evidence that life is an evolutionary emergent phenomenon where inorganic material reactions create life. We already know that’s the case in highly controlled environments. We don’t yet have confidence about the exact mechanism on Earth but based on those experiments it’s likely (& generally currently accepted as the most likely mechanism AFAIK) that the boundary layer of volcanoes (probably underwater) + some crucial initial elements being available causes life to form “spontaneously”. Given the elements required and their overall availability in the universe, it’s also highly likely these conditions reproduce quite readily & life is generally quite abundant. Similarly, significant levels of intelligence within animals seems like quite a common occurrence as well (great and lesser apes, elephants, octopuses, dolphins, wolves etc). Whether or not intelligence + physiological evolution + social evolution to take advantage of that intelligence to build things cooperatively is a huge unknown of course although I think it’s inevitable. On the other hand, how long life sticks around on a planet once it forms is an open question - it’s not clear if a life ecosystem that’s stable for billions of years is likely and I suspect there’s probably a small amount of filtering that happens where planets become inhospitable rather “quickly” and can’t support life for multiple billions of years (e.g. there were probably several events in our history where it could have collapsed). Our type of society is probably much much rarer because you need access to mineral and energy deposits to go through each technological phase. For example, because of all the mining we’ve done, if humanity were to disappear it’s highly likely the Earth would not sustain another technological society because all the “easy to get to” deposits of crucial metals & things like oil are gone and there’s no way to bootstrap a technological society (it’s possible other kinds of resources could be developed to build other kinds of technology so who knows). I think based on our existing body of knowledge, life is likely extremely plentiful throughout the universe at one point in time or another. Some form of intelligent life is highly likely wherever we find any life that manages to stick around through bilions of years. A highly technological adept species of life though is highly likely an extreme rarity and a planet gets one shot at developing it. Whether any manages to escape their home planet remains an open question that likely only we will manage to answer over the next thousands of years if we make it that far.

ghaff 3y ago

idlewords 3y ago

The other part of the open question is how easily life is able to spread across worlds. This is why it's so vital to go look at Mars without contaminating the search. If life spreads easily (whether within the solar system or more widely), then we'll likely find traces of life there that look a lot like our own. If life arises easily, but doesn't spread easily, we may find traces of very un-earthlike biochemistry. And if life is rare, we'd expect to find nothing. Any of the three results would have huge implications. And then rinse and repeat on Enceladus, Ganymede, Europa, and so on. And find a way to look at exoplanet atmospheres and chase stuff that comes in from outside the solar system. Even negative results will add enormously to our understanding.

addicted 3y ago
At this point isn’t Mars already contaminated?
- idlewords 3y ago
  No, almost certainly not. There are individual living microbes and spores on the various landers, but unlike the microbiome that would travel with a human mission, they're not viable and have no mechanism to get to somewhere where they'd be viable.
  - RajT88 3y ago
    I mean, you say that, but also this story was a thing that happened: https://www.cnet.com/science/sea-plankton-found-on-the-outer-surface-of-the-iss/ https://www.cnet.com/science/sea-plankton-found-on-the-outer...
    - vel0city 3y ago
      The leading theory is air currents from the planet slowly contaminated the station over the decades, not contamination before launch. It's also then still pretty protected by radiation still being so close to Eath. Our probes go through pretty tight clean room packaging, shed almost all their outside layers before leaving Earth orbit while still being very toasty, and then get blasted by intense radiation for months and are finally separated by some pretty massive distances on the planet.

creer 3y ago

idlewords was specifically mentioning that we have (found life elsewhere). It was pretty clear to people that there would be no life 750 metres inside the earth crust below another 700m of ocean: too hot, no light, pressure, bla, bla. - And plenty was found. Of course it's an easy counter "Still Earth, haha! Doesn't count". So yes, it's back to the point that whenever we have developped tech to go look, we have found "whatever the tech could find". Except - for now - TV serials radio waves. That's true. And bacteria on Mars. Yes it's a glib way to put it but it's not an unfair answer to that criticism.

NotSammyHagar 3y ago

I went to a biology/astronomy talk where there was a researcher working on the sequence of chemical changes on the early earth without much water or atmosphere would need to create dna base pairs. It was stunning because they basically had a sequence of things and geological discoveries point toward the precursor chemicals being available. It's not that dna was just there. This is not "life arising spontaneously". This is chemicals in an environment where they eventually build dna base pairs. Then after millions of years, perhaps you get microbes and go from there. Meanwhile we are getting water on earth from comets crashing down.

superposeur 3y ago
The “eventually build dna base pairs” (that continue self replicating) is the uncertain and possibly ludicrously improbable step. See for instance https://www.nature.com/articles/s41598-020-58060-0 https://www.nature.com/articles/s41598-020-58060-0 which argues for a probability per exoplanet small enough that it hasn’t happened a second time in the observable universe. On the other hand, one of the self-organizing proposals cited elsewhere in this thread may turn out to be correct and the probability may be much higher. The point is that, while there are some cool ideas on the table, everything hinges on the particular value of this probability (not just a qualitative story of how life might have arisen) and we don’t know what it is. Still relevant: https://blogs.scientificamerican.com/cross-check/pssst-dont-tell-the-creationists-but-scientists-dont-have-a-clue-how-life-began/ https://blogs.scientificamerican.com/cross-check/pssst-dont-...
- NotSammyHagar 3y ago
  Sorry, I didn't see your posting before. The person speaking at the astronomy on tap presentation made it seem much more likely, basically given expected conditions on pre-biotic earth, very likely in a million year timeframe. I'm a software engineer so I don't readily admit I don't know what I'm talking about. Are you in the field and can maybe elaborate on your skepticism? This fellow was pretty certain they've worked out several likely possible paths. This was last year.
  - 3y ago