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2020-09-14, 10:27 AM (ISO 8601)
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- Aug 2007
Phosphine on Venus - "hints" of living beings
So, the news that was leaked a couple of days ago is now fully out: phosphine has been detected on Venus, and the astrochemists have not been able to figure out what process could possibly be happening on Venus that'd generate that much phosphine other than a living being.
Now, I think that most scientists are expecting to learn something new about chemistry, rather than discover life, but still, it's a reason to send a probe to Venus and maybe get it floating in the upper atmosphere where it is a cozy temperature, rather than lead-melting temperature, so all in all, I think this is a great result, even if I don't expect them to find Venusian microbes floating in the high winds.
Grey WolfLast edited by Grey_Wolf_c; 2020-09-14 at 10:29 AM.
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2020-09-14, 10:56 AM (ISO 8601)
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- Dec 2010
Re: Phosphine on Venus - "hints" of living beings
This paper may be relevant to the discussion: https://arxiv.org/abs/1910.05224
This could be a pretty strong biosignature as there aren't any known abiotic processes that make it under 'the usual' kinds of planetary conditions, and degradation tends to pull it out of the atmosphere fast enough that if you see it then it indicates active production. However, it does appear abiotically in gas giant atmospheres. At high pressure and temperature above 800K (according to the paper), it becomes the thermodynamically stable configuration of phosphorous. The average temperature of Venus' surface is below 800K, but not by all that much, so that makes me a bit curious as to whether there would be hotspots that could be responsible for phosphine conversion that would produce enough to explain the atmospheric signature.
I guess we'll see when they actually release the results.
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2020-09-15, 02:36 AM (ISO 8601)
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- Jan 2007
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- Switzerland
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Re: Phosphine on Venus - "hints" of living beings
Relevant:
SpoilerLast edited by Eldan; 2020-09-15 at 02:36 AM.
Resident Vancian Apologist
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2020-09-15, 04:47 PM (ISO 8601)
- Join Date
- Oct 2009
- Location
- In my library
Re: Phosphine on Venus - "hints" of living beings
While I'm skeptical, I'm excited as well. The end result is either we find alien life or we discover something new about chemistry or Venus that boosts our understanding of the universe.
I can't see any real reason not to send akerbalprobe, bit then again I think we should be sending probes everywhere.
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2020-09-15, 05:01 PM (ISO 8601)
- Join Date
- Feb 2011
Re: Phosphine on Venus - "hints" of living beings
Probably the coolest science news of the year so far, and a welcome dose of optimism.
I'm extremely cautious about any possible biosignature, and I have a feeling that ultimately this will be recognized as part of a purely abiogenic process. But either way, this is Science!!! with several exclamation points.
(And yet, and yet, extremophiles....)
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2020-09-16, 07:18 AM (ISO 8601)
- Join Date
- Jan 2019
Re: Phosphine on Venus - "hints" of living beings
My money is on some interesting autocatalytic chemistry, but not 'life'. Would love to be wrong though. The definition I am using would include the existence of machinery capable of replicating a whole class of molecules from some sort of recipe. For example, RNA strands can do a huge number of different jobs, and cells do not need specialised machinery to make a particular RNA machine. By feeding the machinery a 'recipe', it can copy any other RNA machine. This allows 'helper' molecules to exist that do not require their own replication machinery.
It is sort of like the difference between a hard wired electronic control circuit and a computer. The hard wired circuit has fixed functionality, where the computer can easily do something completely different.
I think it unlikely that that sort of molecule would come about in the cloud layer. If life exists there it probably migrated from somewhere. Who knows, maybe there was once macro scale complex life on the surface!
Whatever happens, this is huge. Unfortunately there is a potential down side. If simple autocatalytic reactions do prove to be quite common (outside of full blown life, that will find a way to eat any other autocatalytic cycles), it is going to make finding life far more difficult. It would mean that many biomarkers may prove to be available to autocatalytic cycles without the general purpose machinery that would qualify as life.
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2020-09-16, 08:54 AM (ISO 8601)
- Join Date
- Dec 2010
Re: Phosphine on Venus - "hints" of living beings
I'll be quite happy if its a sustained autocatalytic reaction network. There's evidence that you can get limited evolutionary dynamics in such systems, even without individuation (cells, individual information-carrying molecules, etc). See for example: https://www.mdpi.com/2075-1729/9/4/80/pdf
The transition from limited heredity to unlimited heredity would still be an issue, but this'd be a big piece of evidence that evolution in some form would be likely to be common in the universe, even if cellular life may or may not be.
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2020-09-16, 10:06 AM (ISO 8601)
- Join Date
- Jan 2019
Re: Phosphine on Venus - "hints" of living beings
While I think it would be extremely interesting to have a whole new branch of chemistry that doesn't occur on earth (because life outcompetes it), I couldn't help but be a little disappointed. We already know that autocatalytic systems can exist, and probably do, but hard evidence that they produce molecules we were hoping would be biomarkers makes finding life much harder. Even complex life might be extremely difficult to be sure about.
The autocatalytic work demonstrates that evolution is not enough. You need some sort of information format in order to get something we would call life. If anything it actually makes life less likely. If autocatalytic processes tend to form which consume precursor molecules then it is less likely that a process which utilises information carrying molecules will occur. It would need to outcompete the existing processes. Life would be far more likely if the typical dominant autocatalytic process could evolve into arbitrary complexity, and finding a situation where it is not would be evidence against that.
It could explain the lack of intelligent life if all life first has to beat chemistry, which is certainly interesting. Personally I find the thought saddening, but can see how others would react differently.
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2020-09-16, 11:10 AM (ISO 8601)
- Join Date
- Feb 2011
Re: Phosphine on Venus - "hints" of living beings
I'm not too concerned about any broader implications for life one way or the other, since at this point it's obviously far too early to make sweeping generalizations.
Even if this is "only" a new set of abiogenic reactions, that's still intriguing on its own merits, and certainly worth a sampling mission of some sort. I'm definitely not saddened at the prospect of exploring an entirely new branch of planetary chemistry.
.Last edited by Palanan; 2020-09-16 at 11:11 AM.
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2020-10-26, 09:09 AM (ISO 8601)
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- Aug 2011
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- Sharangar's Revenge
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Re: Phosphine on Venus - "hints" of living beings
Update: Serious Doubt Cast on Phosphine Findings.
It was quite possibly just noise that a 12th order polynomial line fit determined was signal, or that the signal processing from the ALMA telescope introduced an error.Last edited by Lord Torath; 2020-10-26 at 09:13 AM.
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