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> Phosphine can be made from elemental phosphorus by simple acid catalysis. Can you point me to a resource that describes phosphine occurring in nature from an

by brylie 6y ago

> Phosphine can be made from elemental phosphorus by simple acid catalysis. Can you point me to a resource that describes phosphine occurring in nature from an abiotic process? The Wikipedia article on Phosphine[1] describes an acid-based route to create Phosphine industrially, but notes that: > The acid route requires purification and pressurizing. While Venus would seemingly have the needed atmospheric pressure, what about the conditions for purification? > The most likely source is reduction of phosphate in decaying organic matter, possibly via partial reductions and disproportionations, since environmental systems do not have known reducing agents of sufficient strength to directly convert phosphate to phosphine [1] https://en.m.wikipedia.org/wiki/Phosphine https://en.m.wikipedia.org/wiki/Phosphine

alpineidyll3 6y ago
-Earth's atmosphere is at present heavily oxidizing and so phosphine is not common here. Phosphine will always be oxidized to phosphate (which is everywhere on earth and much of it abiotic). You can make phosphine from entirely abiotic common elements and salts literally hundreds of ways. It's almost exactly like saying how many abiotic syntheses of water (OH2) are there (all combustions for starters...) I have a PhD in chemistry from Berkeley and collaborated with nasa astrochemists. I'm not just reading wikipedia FYI ;P
- Rooki 6y ago
  It's a shame they didn't have you on the team researching and writing this paper then. Could have saved everyone a lot of time!
  - throwaway_pdp09 6y ago
    Too many people say stuff on subjects they're not qualified to speak about. Occasionally you get someone who knows his stuff, and I've no reason to disbelieve his PhD claim. A sarcastic response doesn't seem appropriate here.
    - Rooki 6y ago
      I don't doubt his (or her) PHD claim either! The casual dismissal of the work of a team of experts across multiple institutions like this just surprised me, and that parent has a PHD in the field made it even more shocking. The team that worked on this said they were thorough in going through the possible abiotic pathways that could cause this on a rocky planet like Venus. Now of course it's possible they missed something, like parent says: "There's about eleven bajillion abiotic routes to phosphine". I guess it was a sarcastic remark, but maybe parent really could have saved everyone a ton of time and $$. They're publishing as a starting point for the rest of the world to dig into this now, hopefully someone nails down what's happening one way or the other without waiting on a probe to be sent there!
      - throwaway_pdp09 6y ago
        You've made your point very clearly, and I can't disagree. Thanks.
      - andi999 6y ago
        Well, maybe he would have saved everyone time and money, but then there wouldnt be a nature publication. I remember a long while ago, the space agency is not too shy to sometimes publish questionable conclusions
      - YeGoblynQueenne 6y ago
        >> The casual dismissal of the work of a team of experts across multiple institutions like this just surprised me, and that parent has a PHD in the field made it even more shocking. It's a casual dismissal only because it's a comment on HN, rather than e.g. a review comment in a peer-reviewd journal. Otherwise, that's exactly the kind of reaction one learns to expect when one is doing research. Your work will be criticised. Ruthlessly. It's not even a bad thing, long-term, quite the contrary. Only work that has survived the criticism of experts in a field can be expected to make a real impact. And this is really just me being philosophical about it because of course criticism stings and rejection hurts. But you learn to live with it and I think most researchers who have taken a baptism of fire (submitted to a journal- or conference in CS) eventually come to terms with it: people will rubbish your work constantly. Until they are convinced it's good work.
- YeGoblynQueenne 6y ago
  If there was ever a time to listen to the opinions of skeptical experts, that would be this time (or any other time when such a big claim is made). I do have to note though that one of the researchers behind the announcement sounds very much like an expert on Phosphine, in particular. This is from the leaked article: Clara Sousa-Silva at MIT, whose career specialty is studying phosphine, said in a statement: It’s very hard to prove a negative. Now, astronomers will think of all the ways to justify phosphine without life, and I welcome that. Please do, because we are at the end of our possibilities to show abiotic processes that can make phosphine. Finding phosphine on Venus was an unexpected bonus! The discovery raises many questions, such as how any organisms could survive. On Earth, some microbes can cope with up to about 5% of acid in their environment, but the clouds of Venus are almost entirely made of acid. https://web.archive.org/web/20200914003530/https://webcache.googleusercontent.com/search?q=cache:dUWrpm80WHsJ:https://earthsky.org/%3Fp%3D343883+&cd=1&hl=en&ct=clnk&gl=us https://web.archive.org/web/20200914003530/https://webcache.... Sounds to me like there's going to be some er, lively debate around this. Or not, I'm not an expert in any of this, lucky me :)
  - alpineidyll3 6y ago
    What they would love is debate on the basis of this sketchy non-evidence, and it would fit in with the pathological nature of the science community today. Really they should simply be asked to show spectroscopic evidence of some other complex molecules. People need to think less about people's university credentials when they assess credibility. Especially at places like MIT which burn through them like kindling. Clara is a postdoc@MIT, and an expert in the _spectral lines_ of phosphine. The paper she refers to about known abiotic routes is really cursory and by no means exhaustively searches for routes to phosphine (https://sci-hub.tw/https://doi.org/10.1016/j.scitotenv.2018.12.086 https://sci-hub.tw/https://doi.org/10.1016/j.scitotenv.2018....). It considers a handful of reactions for a compound which has millions of chemical equilibria. The most obvious omission is hydrogen sulfide which is all over venus.
    - YeGoblynQueenne 6y ago
      Well, the cat is out of the bag now, as they say, and there was an announcement by the Royal Society, no less. If you're right, there's going to be some very poignant egg on some very prominent faces. Honestly, I have no ability to judge this way or that in this thing. It's completely outside my expertise. Also, I have no idea of how common it is for people to make unsubstantiated claims in astronomy (or is it astrobiology in this case?). In my field, AI, it's common for people to use big words and say big things they can't really back up with anything concrete. I hope that's not the way it is in astronomy. I'm a little concerned by your turn of phrase "the pathological nature of the science community today". If this announcement turns out to be a dud it might make some damage, I guess.
- brylie 6y ago
  Thanks for the clarification. I am genuinely interested but don't know many sources to search related to chemistry.
- ls612 6y ago
  I don't think the issue is that you can't make phosphine abiotically. I think it is that, even at a concentration of 20ppb, there's so much atmosphere on Venus that we are literally talking about many billions of tons of this stuff, and it would get destroyed fairly quickly in the upper atmosphere by solar radiation so there is something down there making very large quantities of this stuff. And there is no good explanation for that.
throwaway_pdp09 6y ago
I'm no chemist and my interpretation is dodgy but purification will (I guess) be to get 'clean' phosphine. But it's not needed pure in venus' atmosphere, it just has to exist. IOW you don't have to purify phosphine to bring it into existence.

by brylie 6y ago

alpineidyll3 6y ago

-Earth's atmosphere is at present heavily oxidizing and so phosphine is not common here. Phosphine will always be oxidized to phosphate (which is everywhere on earth and much of it abiotic). You can make phosphine from entirely abiotic common elements and salts literally hundreds of ways. It's almost exactly like saying how many abiotic syntheses of water (OH2) are there (all combustions for starters...) I have a PhD in chemistry from Berkeley and collaborated with nasa astrochemists. I'm not just reading wikipedia FYI ;P

Rooki 6y ago
It's a shame they didn't have you on the team researching and writing this paper then. Could have saved everyone a lot of time!
- throwaway_pdp09 6y ago
  Too many people say stuff on subjects they're not qualified to speak about. Occasionally you get someone who knows his stuff, and I've no reason to disbelieve his PhD claim. A sarcastic response doesn't seem appropriate here.
  - Rooki 6y ago
    I don't doubt his (or her) PHD claim either! The casual dismissal of the work of a team of experts across multiple institutions like this just surprised me, and that parent has a PHD in the field made it even more shocking. The team that worked on this said they were thorough in going through the possible abiotic pathways that could cause this on a rocky planet like Venus. Now of course it's possible they missed something, like parent says: "There's about eleven bajillion abiotic routes to phosphine". I guess it was a sarcastic remark, but maybe parent really could have saved everyone a ton of time and $$. They're publishing as a starting point for the rest of the world to dig into this now, hopefully someone nails down what's happening one way or the other without waiting on a probe to be sent there!
    - throwaway_pdp09 6y ago
      You've made your point very clearly, and I can't disagree. Thanks.
    - andi999 6y ago
      Well, maybe he would have saved everyone time and money, but then there wouldnt be a nature publication. I remember a long while ago, the space agency is not too shy to sometimes publish questionable conclusions
    - YeGoblynQueenne 6y ago
      >> The casual dismissal of the work of a team of experts across multiple institutions like this just surprised me, and that parent has a PHD in the field made it even more shocking. It's a casual dismissal only because it's a comment on HN, rather than e.g. a review comment in a peer-reviewd journal. Otherwise, that's exactly the kind of reaction one learns to expect when one is doing research. Your work will be criticised. Ruthlessly. It's not even a bad thing, long-term, quite the contrary. Only work that has survived the criticism of experts in a field can be expected to make a real impact. And this is really just me being philosophical about it because of course criticism stings and rejection hurts. But you learn to live with it and I think most researchers who have taken a baptism of fire (submitted to a journal- or conference in CS) eventually come to terms with it: people will rubbish your work constantly. Until they are convinced it's good work.
YeGoblynQueenne 6y ago
If there was ever a time to listen to the opinions of skeptical experts, that would be this time (or any other time when such a big claim is made). I do have to note though that one of the researchers behind the announcement sounds very much like an expert on Phosphine, in particular. This is from the leaked article: Clara Sousa-Silva at MIT, whose career specialty is studying phosphine, said in a statement: It’s very hard to prove a negative. Now, astronomers will think of all the ways to justify phosphine without life, and I welcome that. Please do, because we are at the end of our possibilities to show abiotic processes that can make phosphine. Finding phosphine on Venus was an unexpected bonus! The discovery raises many questions, such as how any organisms could survive. On Earth, some microbes can cope with up to about 5% of acid in their environment, but the clouds of Venus are almost entirely made of acid. https://web.archive.org/web/20200914003530/https://webcache.googleusercontent.com/search?q=cache:dUWrpm80WHsJ:https://earthsky.org/%3Fp%3D343883+&cd=1&hl=en&ct=clnk&gl=us https://web.archive.org/web/20200914003530/https://webcache.... Sounds to me like there's going to be some er, lively debate around this. Or not, I'm not an expert in any of this, lucky me :)
- alpineidyll3 6y ago
  What they would love is debate on the basis of this sketchy non-evidence, and it would fit in with the pathological nature of the science community today. Really they should simply be asked to show spectroscopic evidence of some other complex molecules. People need to think less about people's university credentials when they assess credibility. Especially at places like MIT which burn through them like kindling. Clara is a postdoc@MIT, and an expert in the _spectral lines_ of phosphine. The paper she refers to about known abiotic routes is really cursory and by no means exhaustively searches for routes to phosphine (https://sci-hub.tw/https://doi.org/10.1016/j.scitotenv.2018.12.086 https://sci-hub.tw/https://doi.org/10.1016/j.scitotenv.2018....). It considers a handful of reactions for a compound which has millions of chemical equilibria. The most obvious omission is hydrogen sulfide which is all over venus.
  - YeGoblynQueenne 6y ago
    Well, the cat is out of the bag now, as they say, and there was an announcement by the Royal Society, no less. If you're right, there's going to be some very poignant egg on some very prominent faces. Honestly, I have no ability to judge this way or that in this thing. It's completely outside my expertise. Also, I have no idea of how common it is for people to make unsubstantiated claims in astronomy (or is it astrobiology in this case?). In my field, AI, it's common for people to use big words and say big things they can't really back up with anything concrete. I hope that's not the way it is in astronomy. I'm a little concerned by your turn of phrase "the pathological nature of the science community today". If this announcement turns out to be a dud it might make some damage, I guess.
brylie 6y ago
Thanks for the clarification. I am genuinely interested but don't know many sources to search related to chemistry.
ls612 6y ago
I don't think the issue is that you can't make phosphine abiotically. I think it is that, even at a concentration of 20ppb, there's so much atmosphere on Venus that we are literally talking about many billions of tons of this stuff, and it would get destroyed fairly quickly in the upper atmosphere by solar radiation so there is something down there making very large quantities of this stuff. And there is no good explanation for that.

throwaway_pdp09 6y ago

I'm no chemist and my interpretation is dodgy but purification will (I guess) be to get 'clean' phosphine. But it's not needed pure in venus' atmosphere, it just has to exist. IOW you don't have to purify phosphine to bring it into existence.