On the other hand, we may have instead found evidence of a new abiotic form of phosphine synthesis— I expect scientists will be working hard to propose non-biological processes that could explain these results. I also expect some new Venus probes real soon now.
This definitely could be the result of an unknown abiotic process. It also definitely could be evidence of life.
For 3 billion years, ending about 750 million years ago, Venus was likely hospitable, leaving the tantalizing possibility that we’ve detected the last vestiges of an ancient ecosystem.
Self-promotion: we'll cover this in-depth in Orbital Index (https://orbitalindex.com) this week.
There's about eleven bajillion abiotic routes to phosphine. The authors of this paper are totally crazy-go-nuts riding the hype train. Phosphine can be made from elemental phosphorus by simple acid catalysis. The atmosphere of venus is highly acidic. Venus is so close to earth that space spectroscopy could find a bunch of actually complex molecules that would imply life, if they were there. Phosphine is literally the simplest compound of phosphorus, a common element.
> From what we're told the researchers have concluded that abiotic mechanisms (i.e. ones that do not involve life) that might produce phosphine cannot account for the large amount that they have detected. The phosphine has been detected in the region within the atmosphere of Venus that is considered by some to be potentially habitable. As to what spin the researchers put on this, we'll have to wait for reporters who have the press release or are allowed to participate in the Zoom press conference thing tomorrow at 15:00 GMT to let us know.
some 'researchers have concluded' doesn't invalidate the fact that PH3 is an extremely simple molecule for which there are many known and unknown pathways. It occures naturally in the atmosphere of Saturn and Jupiter.
> 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
-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
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.
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....). 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.
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.
My question would be if the phosphine is being constantly produced from phosphate minerals does that mean that Venus at one point had an oxidizing atmosphere that produced those phosphates?
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.
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.
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!
>> 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.
Generally the paper would at least be glanced at before unloading the criticism though right? Did parent even know how much phosphine they'd found when making the above comments?
I assume the OP, being an expert in a relevant field, has enough information to form and express an opinion. Myself, I am not an expert in a relevant field and so I have no idea whether one needs to know how much phosphine was found before smelling a rat.
From what I've read, the amount of phosphine plays a role, i.e. if there's lots of it it's a stronger sign of life. However, that's what I've read in the lay press that reports on the opinions of experts. Now, the thing about the opinions of experts is that there are always other experts that hold a completely different opinion and when you read an interview with one expert they very strongly support their own opinion, but don't really do justice to the opinions of others- because that's not their job. So it's often hard to know which expert's opinion is closest to the truth by reading what one team of experts tell the lay press. Science is a debate, after all- but not a debate carried out in news sites and internet forums (or at least not primarily there, I understand theoretical phycisists like their internet flame wars).
So, personally, before accepting anything as evidence of this and that, I'll just wait patiently until the dust has settled and the experts have agreed to disagree.
I wish more people did that when it came to my own area of expertise, btw. What I say above is what I've observed on reportage of my own field in the lay press.
As I see it the probkem us he said "You can make phosphine from entirely abiotic common elements and salts literally hundreds of ways" but doesn't state them, and got justly criticised for it.
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
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.
From a quora post by the same author of the tweets:
> 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
> there very well could be an abiotic source but that alone would be an amazing discovery. However we must deploy Occam’s Razor and suggest the simplest explanation and the evidence suggests the simple explanation is biological sources, life.
Wouldn't a better announcement be "Phosphine detected in Venus atmosphere". Maybe it's compelling evidence for life, but claiming "Signs of Life Detected" seems a bit premature, no?
And from the link on the author's Twitter bio:
> Over the long, winding arc of his career, Brian has built and run payments and tech businesses, worked in media, including the promotion of top musicians, and explored a variety of other subjects along the way.
Not exactly who I thought would be announcing the discovery of life beyond our planet.
> Wouldn't a better announcement be "Phosphine detected in Venus atmosphere".
Better announcement for whom? For the general public, which largely has no idea what phosphine is but has a decent chance of guessing it is a chemical, that title would not give them any indication that the article might be interesting to them.
For most people the only thing that makes phosphine on Venus interesting is that it might be a sign of life, so you want to have that somewhere in the title.
Did you read the article? There's going to be a paper published tomorrow in Nature and the MIT scientists who wrote it will be doing a press conference. This Brian guy is just amplifying the news - he's not the author of the study.
Yes, I read the article. The discovery does sound compelling. I'm commenting on his amplification strategy ("Signs of Life discovered on Venus") rather than just presenting the facts ("Phosphine detected in Venus atmosphere").
I prefer my science news without a hype man but the author seems to take quite the initiative on Quora: "However we must deploy Occam's Razor and suggest the simplest explanation and the evidence suggests the simple explanation is biological sources, life."
It's pretty sensationalized and coordinated like a PR campaign.
If you watch the video on his Twitter feed, the scientists themselves seem to focus on the science and don't claim to have "discovered life on Venus", so they do seem well intentioned. And their discovery certainly does sound interesting and potentially significant.
“Signs of life” has more information content than “Phosphine” - I had no idea that Phosphine is a sign of life, and that is a completely objective description of it from my new understanding. A sign of life does not mean life.
My understanding is that the presence of it strongly implies life on Venus. Just because people have a prior on that doesn't mean the evidence is inherently weak. If it turns out there is bacterial life on Mars and on Venus (both potentially the case) people who claimed we needed "extraordinary evidence for extraordinary claims" will look conservative in retrospect.
Good journalism (and any information sharing) is about delivering meaning, not just facts. Facts divorced of context tend to lack meaning to all but those that fully understand their context, because they're prone to misunderstanding.
It's completely appropriate to center a headline around the likely meaning of the phosphine discovery rather than the discovery itself, because almost nobody is an astrobiologist. The scientists who study this stuff are just as compelled by the question of life on other planets as a layperson, because its discovery would be extremely meaningful to us as a species.
The question is not whether headlines should be represented as facts or their meaning, its whether the meaning that is presented is supported by the facts. In this case, it seems warranted.
"I expect scientists will be working hard to propose non-biological processes that could explain these results."
If scientists don't attempt to explain a dramatic claim using other mundane explanations I'd be very suspicious of calling them scientists. Occam's razor is a useful tool. Be very suspicious if dramatic claims aren't tested. Otherwise I have a bridge for sale...
"I also expect some new Venus probes real soon now."
Maybe. You should also expect a lot more telescopes of all descriptions and varieties to be pointing at Venus. Multiple compute clusters are likely digging through old and new imaging data even as I write this.
"leaving the tantalizing possibility that we’ve detected the last vestiges of an ancient ecosystem."
According to the paper in your first link [0], PH3 gets destroyed by ultraviolet light-related chemistry, and so has a short lifetime in planetary atmospheres (section 2.3 on page 7, though that's specific to Earth's atmosphere). I assume this means if they've detected phosphine, there must be an ongoing process generating or replenishing it.
Perhaps possible Venus' very thick atmosphere shielded it from UV? Or a large pocket of it was recently released due to gelogic activity. Just spitballing, I don't know enough about phosphine chem to know if that's feasible.
Just so people don't miss this, it's about some scientists who spent several years looking for abiotic forms of phosphine synthesis, couldn't find any that could produce significant amounts, and concluded that phosphine is a really good biosignature.
Conveniently, BepiColumbo is already scheduled to do a flyby next month for a gravity assist en route to Mercury, with some brief atmospheric science while there. Probably impossible to alter the trajectories at this point, but it sure would be tempting to stay and do some more in depth observation...
>we may have instead found evidence of a new abiotic form of phosphine synthesis
I think this will be the critical thing to effectively communicate publicly. Given what we know about phosphine synthesis, a subject I presume most people aren't super familiar with, how confident are we that a new abiotic process is possible? Or is it so unlikely that life is a more plausible explanation?
Those aren't rhetorical questions. I wonder about the relative plausibility of one vs the other.
> This means either this is life, or it’s some sort of physical or chemical process that we do not expect to happen on rocky planets. We really went through all possible pathways that could produce phosphine on a rocky planet. If this is not life, then our understanding of rocky planets is severely lacking.
Thanks, but I was familiar with that conclusion already and that's not quite what I'm asking for.
What I'm asking is some ballpark idea of the relative plausibility of (1) microbes, compared to (2) having discovered some new physical/chemical processes.
Is it a case where we feel like we've got our understanding of (2) locked down, and so "it would have to be a chemical process we've never seen" is a way of saying it's highly likely to be life? Or is it very plausible that we do have much more to learn about chemical processes, and it's just a face value statement? Are we talking 99% life, 1% likelihood of new process? 50/50? Something else?
Right. This just reminds me of the news cycle from 2011 or so about a paper reporting neutrinos moving at faster-than-light speed. Which turned out to be a false alarm.
Why would it be surprising to find bacteria next door? If life is common in the universe, this would be exactly what you’d expect. And there is plenty of reason to think life is common in the universe.
> Why would it be surprising to find bacteria next door?
No one said it would be surprising (though it would to a great many people), the point is that it would require a LOT of assumptions about how life develops to get us to that point whereas human ignorance is the sole assumption we need to make to assume that these measurements are not life-related.
I think life is everywhere in the universe and that we will find that it descends along a great many entropic pathways in a great many frames of reference. But I also believe any given hint of life is more likely than not going to be related to human error, only because we have so many assumptions we need to make until we understand the underlying processes better.
Ok, potentially stupid question, but isn't "life" just such a "pathway"? Meaning an organism already assumes a complex system of chemical reactions, and then some other chain to produce phosphine? So is it really hard to believe that if "our understanding of rocky planets" already assumes something as complex as life is possible, then something less complex than life (but still possibly quite complex) which produces phosphine is also possible?
> something less complex than life (but still possibly quite complex) which produces phosphine is also possible?
Of course it is possible. Everything is possible. But we have never seen such a process and we have seen life. So if life explains it but nothing else does except "possibly something" then life is the simplest explanation. The alternative really is no explanation, only speculation.
We could be living in a simulated universe, everything is possible, the simulation can include logically contradictory simulated laws of physics in other words "miracles". But such speculations don't really explain anything, they only say it is always possible that some other explanation may be found at a later time. Until an alternative equally good or better explanation is found it is best to use as working hypothesis the simplest explanation which explains all the observations, which seems to be "life" according to these scientists.
Yes, "life" is a "pathway". The link for the paper didn't work for me, but I'm thinking the issue here is the "pathway" with "life" involved is now the simplest system that can produce the observed results.
From the Quora article:
"The volume of Phosphine observed was stunning. They ruled out minerals blown into the atmosphere, volcanism, lightning and other known sources as there is simply no process that could maintain this abundance. So much Phosphine was observed we could conclude that the atmosphere of Venus is “teeming with life”."
One wonders if that isn't proving too much; if the atmosphere of Venus is "teeming with life" one would not expect the only such signature to be an excess of phosphine only noticed after centuries of observation.
I mean, I realize not all life necessarily engages in photosynthesis that emits highly reactive O2 into their atmosphere and radically and highly visibly transforms the entire atmosphere, but since the only energy source on the geological time frames those bacteria are going to be able to count on in the high atmosphere is going to be sunlight one would rather expect "teeming with life" to have very obvious spectra effects, i.e., "turning the planet funny colors" as life uses light energy in some sort of photosynthesis-like reaction, not merely creating an unexpected abundance of phosphine.
"Life scraping by" is a lot easier to believe than "teeming with life". "Teeming" life has no compelling evolutionary reason to also be well-hidden from us, and a lot of pathways to being very obvious as it exploits the energy available.
After some more thought, it's also just plain hard to believe in a pure atmospheric bacterium. I'm not sure we even have such a thing on planet Earth. Plenty that survive in the atmosphere better than expected, may even actively use it to spread, but nothing that lives up there. (Links to corrections solicited.) We don't routinely experience green days because of a mass of atmospheric bacteria blowing in above us and blocking the sun as they photosynthesize.
Energy it has in abundance, but where is it getting the atoms it's made out of? Carbon and oxygen are readily available, but you need more than that. Water is minimal in the atmosphere, and mere presence isn't enough, you need to be able to gather it against the strong osmotic pressures pulling it back out. (Earth life seems to have needed hundreds of millions of years just to grow on Earth land, a wildly more friendly environment than an atmosphere that still has puddles of nearly pure water to work with. Even a cloud is, by comparison, water-poor.) How do you get any nitrogen? Lightning may fixate it as it does on Earth, but then it immediately dissipates. It's very difficult to use N2 directly, although some Earth life manages. After that what's left in the atmosphere is some vicious acids and some noble gasses. So in the basic CHON equation, C & O are covered, N is exceedingly chemically difficult, and H is almost missing. Trace elements are also not available because they don't float, except sulphur (we use this ourselves, but it's not the most useful one), and while bacteria may get by without using as much of them as we do, I'm not sure you can make a life form out of nothing but CHON, let alone CO(Nish).
My bet is this will turn out to be one or more of the basic abiotic phosphine processes accumulating over long, long time because whatever processes that would consume phosphine are for some reason suppressed (e.g. lack of oxidants?).
What’s great here is that this means it’s potentially a profound and important scientific observation either way! Obviously one is a bit more profound than the other, but nevertheless.
On the off chance it is life, it might be a relative. Earth and Venus are close enough together for asteroid impacts to throw debris to each other. And bacteria is strangely resistant to the conditions of outer space. See the panspermia hypothesis.
> I expect scientists will be working hard to propose non-biological processes that could explain these results.
(Serious question, and I don't mean 'good' or 'bad'.)
Would that be a negative result, or positive? Or does the phrase have no meaning without reference to what you're looking at; so it'd be simultaneously a negative result for life on Venus, and a positive result for abiotic phosphine production processes?
The aim to publishing this paper is probably that: first of all to invite as many as possible scientists to propose new abiotic pathways that would have been overlooked.
The sensationalism is probably an excellent way to pick their skepticism, so get more people to find counter-arguments.
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This definitely could be the result of an unknown abiotic process. It also definitely could be evidence of life.
Some papers to check out:
- https://arxiv.org/abs/1910.05224
- https://www.liebertpub.com/doi/10.1089/ast.2017.1783
For 3 billion years, ending about 750 million years ago, Venus was likely hospitable, leaving the tantalizing possibility that we’ve detected the last vestiges of an ancient ecosystem.
Self-promotion: we'll cover this in-depth in Orbital Index (https://orbitalindex.com) this week.