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.
Looks like broken CSS or broken scrolljacking. If you hit "stop" before everything finishes loading, there is indeed content:
* A subscription box
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* The most recent issue of the newsletter (also accessible from the archive without this trick) (with this trick it also starts with HTML and CSS dumped to the page instead of interpreted)
This leaves (2), which is a bear because it states a negative. The claim that the phosphine on Venus is biological in origin requires no feasible route to the substance given the known chemistry of the planet's atmosphere.
Given that Venus' atmosphere is a complex mixture held at very high temperature and pressure, the "sign" seems pretty weak here.
>Given that Venus' atmosphere is a complex mixture held at very high temperature and pressure, the "sign" seems pretty weak here.
The phosphine signal is coming from a portion of Venus' atmosphere that has pressure and temperatures similar to that of the the Earth's surface, according the the Earth and Sky article.
Not really. Phosphine is broken down by UV light so having it be concentrated higher in the atmosphere, where it's exposed to more UV light, would be difficult to explain via transport from a lower altitude source.
This is a possibility but we’ll have to see what the paper makes of this, if anything. It may depend on knowing more about the motion of the atmosphere. It was also an unexpectedly large amount of phosphine apparently, more than would normally be stable at that altitude (so it’s definitely being renewed).
But again, this is just a string of tweets—hard to say anything without the paper!
I think it's debatable, at best, whether Occam's razor would favor "an unknown process" over a known biological process. Especially when some research apparently has already been done, without success, to discover alternate processes.
(And, by the way, the unknown process could also be biological!)
You're implying we don't have any information at all. We do.
Even if you argue is it's limited, to our knowledge bio processes outside of earth has been zero. Whereas, non-bio chemical processes is greater than zero. So now people want to bet on that it's bio??
Milky Way contains on the order of half a trillion star systems. Would having, say, a million planets carrying some form of life in our galaxy alone qualify as “rare”?
To be fair, I wouldn't consider that rare. When we talk about life, we usually think in terms of are we alone. If there are a million planets with life, life isn't rare, regardless of what percentage of planets have life.
You don't know if an unknown route to phosphine generation would be simpler and more likely, you would just find such an announcement more mundane, which you mistake for it being more plausible.
Invoking Occam's razor to compare two unknowns makes about 0 sense.
"We should also not rule out far more complex life from the observations of Phosphine. It is quite possible we will observe life as large as a Whale on Earth quite happy suspended in the gravity waves of Venus." WTAF?
Also, how did the video in his tweet somehow become available a day early as well as the Earth&Sky article. Something doesn't smell right here. The explanation is that the Earth & Sky article was put up early by mistake and pulled.. and this guy happened to find it. Another explanation could be that an article was written to look like an Earth & Sky article and put on a google drive... and that he got a couple of friends to make the short video on the MIT campus. Otherwise how does that video somehow appear today, a day early as well as the article?
He does seem like a bit of a "character." But maybe he had a webscraper that just happened to catch the premature post, and is just trying to self-aggrandize on a real scoop? Nasawatch [0] is saying that several sources have confirmed it to them...
Probably a leak from one of the embargoed reporters is more likely, if it's true. Obviously we'll find out soon. But if the Earthsky.org story a fake, he certainly did a vastly better job producing the fake than he did self aggrandizing off of it.
It seems to be His Thing and he has been looking at the preprint of the paper since a month ago. There are people outside the normal academic framework who are knowledgeable and even influential within a specialist field.
> Another explanation could be that an article was written to look like an Earth & Sky article and put on a google drive.
I've never in my life seen someone fake a document that good. It's close to impossible under current conditions to appear in the wild. The Russians might be able to, for instance, but there's no circumstances they would, the cost to reward is way to high.
Here's a long-form article about this that appears tomorrow in Earth & Sky. It was apparently published early by accident, and taken down; hence this Google cache link.
Simply put, a gas that shouldn’t be there, and on Earth is considered a conclusive biosignature: phosphine, a very stinky gas. As far as scientists know, there are only two ways to produce it, either artificially in a lab, or by certain kinds of microbes that live in oxygen-free environments. Since it is rather unlikely there any alien labs on Venus, that leaves microbes."
Or it reveals, that we still don't really know what is going on on venus, which chaotic atmosphere and vulcanic activity might very well result in the specific "lab conditions" to create phosphine.
So, it is a very interesting find, worth investigating, but I just for the existence of a gas, I would not shout "proof of alien life", yet.
> As far as scientists know, there are only two ways to produce it, either artificially in a lab, or by certain kinds of microbes that live in oxygen-free environments.
Philippe Gengembre (1764–1838), a student of Lavoisier, first obtained phosphine in 1783 by heating phosphorus in an aqueous solution of potash (potassium carbonate).[4][5]
And how do you propose to obtain elemental phosphorus in the atmosphere of Venus? As a side note, phosphorus is actually named after Venus the morning star, light bearer, etc because it is highly reactive and glows slightly in the presence of oxygen.
Yes, the article was clear on that. There are methods to produce it "naturally" or in a lab, but no explanation fits the amount of gas they have detected. So either they do not understand conditions on Venus, there is a new method to produce it or there is a microbe producing it.
Not for me. Finding life from elsewhere than Earth would be by far the most significant scientific discovery in human history. (Again, just a personal opinion; I have no objective argument to back it up).
I disagree, close in proximity to 'stunning', however, finding true unique life that originated on a planet by itself organically goes a long way towards proving/disproving the fermi paradox.
I think it was maybe Carl Sagan who said (something like): if we find life in our solar system it's probably game over for us, as it means the great filter is likely ahead of us, not behind us.
Though, you can take one look at the world right now, and not see how easy it would be to just destroy it if we aren't careful (and we're not being careful).
Yep, I agree with him that we're likely to find bacterial type life all over the place where there's water. At least if we can travel to places. But 'complex life' is going to be beyond scarce.
Though it's quite possible that if there is something on Venus or Mars it's Earth-origined, since conditions here 4 billion years ago look better for abiogenesis.
There is the power law heuristic, that 90% of results are often due to 10% of phenomena.
If there are several filters, then they may differ in effectiveness by many multiples, and then it's semantics as to whether you say any beyond the largest are "great".
Just FYI - no probes have ever been 100% sterilized, because it's simply impossible without destroying them. Even the most sterilized probes and rovers that we've sent to other planets will have contained at least some bacteria.
If that happened, I think we'd be able to determine that by sampling and analyzing the microbes.
I think a more interesting concept would be exchange of microbes between Venus and Earth at some point in their distant past, and then could we might be able to date that (those) event (s) via their molecular clocks (https://en.m.wikipedia.org/wiki/Molecular_clock)
If this were true and if abiogenesis had been independent from life on Earth, we could basically assume that it is certain that life arises on planets with suitable conditions (as they were once in the history of Venus).
In this case, the universe basically must teem with life in one form or another.
These might be the biggest ifs one could imagine but I'm really excited for the follow-ups...
(Cross-posted from another thread, as the other doesn't seem to gain traction)
If this is true, I expect several missions to launch ASAP to try and test this hypothesis. If we could prove abiogenesis separate from Earth we will have good proof that life should be abundant.
Very exciting news, I'm hoping that it is proof of life as that will give increase interest and funding for space exploration.
If it all holds up, it means that we saw evidence of alien life for a hundred-plus years (the "unknown absorbers") before we realized it and verified it. Point being, humans can be "slow on the uptake" (and not unreasonably so, given the distances, time scales, and complexities involved).
See also the Silurian Hypothesis [0], which I think just got a lot more interesting as a thought experiment.
> Was There a Civilization on Earth Before Humans? [...] Gavin and I don’t believe the Earth once hosted a 50-million-year-old Paleocene civilization.
Betteridge's Law confirmed. We can track down fossils billions of year back by observing the way they shaped the encasing rocks, and not once have we noticed a ceramic shard, a metal bit or the silhouette of a plastic object.
> There are fossils, of course. But the fraction of life that gets fossilized is always minuscule and varies a lot depending on time and habitat. It would be easy, therefore, to miss an industrial civilization that lasted only 100,000 years—which would be 500 times longer than our industrial civilization has made it so far.
> And then there’s all that plastic. Studies have shown that increasing amounts of plastic “marine litter” are being deposited on the seafloor everywhere from coastal areas to deep basins, and even in the Arctic. Wind, sun, and waves grind down large-scale plastic artifacts, leaving the seas full of microscopic plastic particles that will eventually rain down on the ocean floor, creating a layer that could persist for geological timescales.
Sandstones. Sandstones originate as far as hundreds of million years in the past. Occasionally they harbor fossils, which are indeed rare. But a lot of sandstone is made of sanded up organic material which we can readily identify, even if we can't point to the specific organism they originated from. We only need a tiny industrial-related grain of sand (ceramic, glass, metal, plastic traces) to point to a past civilization. Nobody ever noticed such a grain of sand.
Sure, and the article mentions other possible signs of civilization as well, then it goes on to say:
> So it might take both dedicated and novel detection methods to find evidence of a truly short-lived event in ancient sediments. In other words, if you’re not explicitly looking for it, you might not see it. That recognition was, perhaps, the most concrete conclusion of our study.
I'm not bullish on pre-historic civilization, and neither is the article, but the takeaway is we may not have reason to expect that we'd have found these tiny industrialized traces without a search aimed specifically at them. As far as I know, such searches have not been carried out in earnest to date.
We've put old rocks under the electronic microscope. That's how we identified billion year old cyanobacteria fossils. While there is no readily available comprehensive record of who searched for microfossils by looking at what old rocks, with or without a microscope, it's not like it's a new idea.
I feel like we're talking past each other here. The very first sentence of your link says "The cyanobacteria have an extensive fossil record." In the next paragraph it says "Cyanobacteria are among the easiest microfossils to recognize. Morphologies in the group have remained much the same for billions of years..."
So not a truly short-lived event in ancient sediments then.
It's unlikely we live in a dark forest. The resources necessary to execute entire civilizations across interstellar space would be literally astronomical.
They would be comparable to resources needed for sublight interstellar travel. If you can get a colony ship to the nearest start at 0.9 c, you can also send an equivalent-weight chunk of matter towards someone else's planet and don't slow down.
Or perhaps once a certain level of technology is reached, the civilization advances so fast as to no longer be recognizable. Perhaps it's not a filter but rather a lack of imagination. What appears to be the universe and all things to us could be a limited as a drop of water to a paramecium.
Why would it be confirmation of Great Filter? It's quite possible that life is abundant in the galaxy but that intelligent life is not common and especially industrialized civilizations.
I don't understand with this fascination with the Great Filter. I am sure there are many filters out there, from having a Sun that lives long enough, that doesn't throw off flares very often, need for a magnetic field to shield advanced organisms, water, fossil fuel creation, gravity that can be beaten with fossil fuel rockets, big moon to reduce number of asteroid hits to the planet, just enough water to have continents yet plenty to reduce temperature differences, no tidal locking, ...
Essentially it's the fermi paradox. If life is out there, why aren't there signs? The universe should be teaming with life but isn't. There's a few reasons why... the Great Filter is a hypothesis that basically means almost all life hits a wall where it dies out no matter what. No life so far that we know has ever made it past this filter.
For the same reason the large dinosaurs died out. Life as we know it operates best within fairly narrow mass scales and energy level ranges. Those are both several orders of magnitude away from the quantities needed to produce effects observable at interstellar distances.
The universe should be teeming with life but isn't.
We currently have no good evidence that it is. That doesn't mean it isn't, just that our detection methods aren't yet up to the challenge. Basic information theory suggests that they may never be. Advanced civilizations will use coherent EM radiation for a limited time only. The radiation they do generate in the long term probably won't be wasted by letting it escape isotropically into space.
Also, at some point they may come to understand that drawing attention to themselves isn't a good survival strategy. A civilization that is advanced enough for us to observe is also advanced enough to hide from us.
> Those are both several orders of magnitude away from the quantities needed to produce effects observable at interstellar distances. (...) our detection methods aren't yet up to the challenge. Basic information theory suggests that they may never be.
Not really true. There are more signs of life than just radio waves. One - like in the article - is chemistry. Planets that seem to be very far from chemical equilibrium are objects of interest, as this may imply there is a complex system that's actively fighting entropy. I.e. life. For instance, aliens with powerful telescopes and good understanding of geology could conclude Earth has life on it by observing it keeps a surprising amount of oxygen in the atmosphere, where it should have already oxidized everything instead.
Yes, really true. Look at how hard it was to establish the presence of the PH3 absorption line on the planet right next door. We are not able to make that kind of observation on extrasolar planets yet, at least not beyond very rudimentary levels. Hopefully someday, but certainly not now.
Admittedly Earth's oxygen signature would be a lot easier to detect than a minute quantity of PH3 on Venus. But we wouldn't have been able to look for that either until just a few years ago. Even to a seasoned RF engineer, ALMA and JCMT are indistinguishable from magic.
Fair enough. What I'm saying is that detecting anomalous chemical composition of exoplanet atmospheres seems almost reachable with our current capabilities, and - unlike radio signals - is an indicator we can't really hide. So aliens slightly more advanced than us could be looking at that.
Life, as we know it, only exists in one single known location in the Universe: Earth.
If we assume life is abundant in the Universe, then we should be able to pick up signs of others, such as radio signals, or bio-indicators in other planets' atmospheres, and so, we ask where the aliens are.
Since we don't find any, we then assume that there is something preventing this abundance of life from developing into something we can detect, and something's called the Great Filter.
As of yet, we only have a single point of data, and since we're still here there's some speculation that we've allready passed through the filter. Another data point would mess up the math a bit and we could, statistically speaking, end up with a scenario meaning we still haven't passed the filter, and that we might still have an apocalyptic event wiping us out.
Life on Venus would give us a better idea of what to look for in other places, and that might help us narrow down the search a bit and find other places with life.
Intelligent life is a different matter. We don't know how common it is for
1) a planet to have formed around a star with the right composition of materials
2) have the exact right conditions for life to form early
3) for that life to survive for billions of years while
4) building up large reserves of substances that can
5) be used as fuel by a tool using bunch of talking apes
6) propel their civilization's technology far enough to match ours
7) send a signal that can reach our specific little dot
8) for that signal to be reach us during the miniscule time-frame that we've been able to pick it up.
I mean, what if the glory days of the Milky Way was 500 million years ago and we're developed just a little to late to be able to see the last remnants of galactic civilization crumble to dust? What if we just happen to be the first, and we develop past such technology before anyone else develops it?
Intelligent life doesn't need to be very common before you should expect to be pervasive.
We're a matter of years from originating von Neumann machines ourselves, so any civilization with thousands or millions of years head start should have incredible galactic spread.
> so any civilization with thousands or millions of years head start should have incredible galactic spread.
No, we're saying that that life didn't even reach "civilization". Humans are a blip in time compared to the dinosaurs, for example - we may well be the anomaly, but life still be abundant.
Seems more likely to me that if there is life on Venus, it was probably carried there from Earth at some point and probably has DNA/RNA base just like Earth life. Would be very interested if it was life with a completely different mechanism for reproduction.
Indeed. All else being equal, I'd expect evolution to progress faster in hotter environments with more solar radiation. I wouldn't be surprised if Venusian microorganisms were more advanced, adaptable and capable of surviving an interplanetary journey than Earth ones two billion years ago.
I like to think that if we could dig beneath the surface we’ll find the remnants of an underground civilisation there... sort of like the martians from Broken Angels, but on Venus.
We could already pretty much assume that, seeing how life appeared on earth almost immediately (geologically, anyway) after it was physically possible. Even panspermia is kind of a stretch when explaining that timeline. But yeah, an independent origin would clinch it.
Phosphine found exactly in the "habitable temperature" cloud range unexplainable by all current abiotic models, which meshes up with other observations of "unknown absorbers" in the same cloud range, which researchers have modeled to be particles about the size of bacteria.
"What is curious about Venus’ clouds – other than that they are unlike anything on Earth – is that in those clouds are mysterious dark patches, dubbed “unknown absorbers” by scientists as the tiny particles that make up the patches soak up most of the ultraviolet and some of the visible light from the sun and thus affect the planet’s albedo and energy budget.
The patches were first observed by ground-based telescopes more than a century ago. They ebb and flow over time, changing their distributions and contrasts.
“The particles that make up the dark splotches, have been suggested to be ferric chloride, allotropes of sulfur, disulfur dioxide and so on, but none of these, so far, are able to satisfactorily explain their formation and absorption properties,” explains Yeon Joo Lee, the senior author of the new report.
On the other hand, Limaye notes observations that the particles are about the same size and have the same light-absorbing properties as microorganisms found in Earth’s atmosphere, and scientists, beginning with the noted biophysicist Harold Morowitz and astronomer Carl Sagan, have long speculated about the possibility that the shadowy patches in the clouds of Venus are, in fact, microscopic life."
https://news.wisc.edu/mysterious-cloud-absorbers-seen-to-dri...
They are implying the great filter is actually the current step (advancing towards colonization explosion). The next step would be colonization explosion (aka colonizing space or other planets), but that could be cut short due to civilization eradicating itself. This is thought to happen either via climate change, nuclear war, or artificial intelligence wiping us out.
I personally am not a fan of the AI destruction theory because I'd expect AI to replace us and expand into the solar system. If it got to the point where it could kill all organic life, then I'd bet it's unlikely for AI to die off with us as well. Just my opinion though...
I think it’s plausible an AI could be able to wipe out humanity before it is able to secure its own indefinite existence. So there’s a scenario in which is wipes out all Earthly life/intelligence.
It could be as simple as a microbe that eats an elementary molecule in our bodies that is so foreign our immune system can't spot it. No need to target us directly.
Quite likely; we’re pretty closely related to those, and multiple species viruses show up all the time. It would be more surprising, though, to find a virus which was pathogenic to, say, both us and archaea, and any Venus life is probably more different to us than archaea are.
A bacteria analogue is possibly more of a risk; those can be less fussy.
We get infected by bird viruses all the time, and they're not even mammals. A virus that evolved in mammals infecting different types of mammals is very likely.
Toby Ord's book The Precipice does a good job evaluating them. Top contenders are AI, bioengineered viruses, nuclear war, and climate change, with natural disasters that we fail to avert/mitigate, like asteroid impact or supervolcano eruption as a distant aslo-ran.
That could be it, but it also could be just that all the low hanging fruit is all taken. Like Newton is a genius for coming up with an equation for making delta-x really small, I could have come up with that and I don't even dabble in alchemy.
The space shuttle was meant to be reusable - it was built 40 years ago in 1980.
I'm not saying there is no new tech, it just all seems incremental, not revolutionary. When I was younger every day it seemed there was something new. Today, not so much.
You might just need to pay attention to the right things. Genetics is making steady progress and promises to revolutionize almost everything. Machine learning seems to be applicable to most things and if only suffering from a lack of optimization. The road to space is opening and we’re about to find out just how many new technologies will be made possible with unlimited solar power, microgravity, and untapped resources.
There's a lot of talk about the great filter this, and the great filter that. Even if life is abundant, what gives you the impression that civilization level intelligence would be? Out of all the species that ever roamed the earth, only a single one has reached this point. Perhaps it's an absolutely incredible fluke or glitch in our biology that is one in a [insert astronomical number].
It's tempting to think something in the lines of "oh but if it happened here in our little shitty solar system, it can't be very special". But that's more or less the anthropic principle.
Unfortunately people still think very teleologically, as if nature works in a progressive fashion towards some structured end; this tendency is deep in western thought all the way back to Plato (and probably beyond), and it's all over science fiction.
The core observation is that organisms with an ability to model the Universe, even if imprecisely and in a tiny space-time neighborhood, increases the chances of survival. See the ubiqutous living beings with a nervous system. The hypothesis is that increased precision and/or size of the prediction bubble is correlated with survival fitness, which, in the limit, gives raise to beings with a God-like ability to predict the Universe. It's a relatively simple inductive argument.
Even if it is true that "in the limit" increased foresight implies increased fitness, it doesn't necessarily follow that being with God-like foresight exist.
That said, IMO there's a lot of things that could confound the usefulness of increased foresight. After a certain point (which humanity has likely passed) foresight is not a particularly visible measure of fitness except in those rare extinction events that require significant cooperation to survive. I suppose that even given that foresight is the most valuable trait for long-term survival of a species, it's very rare that it is selected for beyond a certain point because the events that it allows a species to survive are too rare to be selected against.
The hypothesis also makes a huge assumption: that if intelligent civilizations were common, they would be detectable by us. The radio waves emitted by our own civilization don't go that far (compared to the distance between stars) before becoming nearly indistinguishable from background noise.
It’s wasteful to spend the power to broadcast up into the sky when no viewers are up there; more focused directional transmitters, more sensitive receivers which allow lower power signals, more information sent over cable and fibre optic and undersea transmission lines and point-to-point satellite, more microwave and laser links compared to spam-everywhere radio broadcasts.
As I understand it, the most visible stuff would be TV signal and over the horizon radar. TV signals have gotten less powerful, over the horizon radar is less of a big deal than it used to be. In another 50 years, will terrestrial TV, or any high power terrestrial radio, be a thing at all?
Some proportion of civilizations would develop to the point that their signals are detectable to us (this is a parameter in the Drake equation). Since we haven't detected anyone, there must be some problem in reaching that point.
On the other hand, stars are extremely wasteful. A technological civilization will, eventually, encase their sun in an energy extracting Dyson swarm. So why isn't the sky full of dim uniform-distribution infrared blobs?
The above link is about AI, but it could apply to any alien species just as well.
Any organism living in a thermodynamic universe and subject to competition and evolutionary pressures will develop instinctual drives that align with resource acquisition, replication, and survival. As the above link details this surprisingly holds true even when you remove evolution and consider designed minds.
Even if a hypothetical civilization didn’t care about resource acquisition, replication and survival, they’d be out-competed by one which did. So where is that civilization’s ever expanding sphere of Dyson clouds?
The authors referenced at the above link don't use that seemingly unwarranted tone of certainty. I can't see anything in Omohundro's papers of anything like the same flavour, and Bostrom's conclusion is the sensible-sounding
It should be emphasized that the existence of convergent instrumental reasons, even if they apply to and are recognized by a particular agent, does not imply that the agent’s behavior is easily predictable. An agent might well think of ways of pursuing the relevant instrumental values that do not readily occur to us. This is especially true for a superintelligence, which could devise extremely clever but counterintuitive plans to realize its goals, possibly even exploiting as-yet undiscovered physical phenomena. What is predictable is that the convergent instrumental values would be pursued and used to realize the agent’s final goals, not the specific actions that the agent would take to achieve this.
I’m not what you’re picking up on other than academic prose. The very quote you give is very certain that convergent intermediate goals would be pursued.
There are a lot of problems with the dark forest hypothesis, the most critical for this purpose being that it is not a stable outcome. A civilization with the capability to create a Dyson sphere and harness the power of an entire star could easily defeat any invader attracted to their presence. E.g. with gamma-ray lasers that fry anything and everything that might be hostile.
Even with the most advanced technology we can imagine, you can't expect to be able to detect a neighboring civilization, cross the gap between stars with an invading fleet, and arrive with enough power to overwhelm defenses every single time. Local development of solar system resources is inherently an exponential process, whereas mustering of interstellar resources is quadratic. A potential dark forest / wolf entity (I much prefer Alastair Reynolds over Liu Cixin) would have to arrive right within the (cosmically brief) window of opportunity in which a developing civilization announces its presence but before it achieves Type II status on the Kardashev scale. Statistically, someone will eventually be lucky enough to avoid the wolves long enough to get that far, and then they'd have the capability to defend themselves from any plausible enemy.
Where are the Dyson spheres of those civilizations?
I have wondered about this too. I suppose the reasoning is that every solar system has a massive source of energy in the middle of it, and that mega civilizations would be stupid to not utilize it.
Sounds probable, but I can see many possible reasons not to bother. Not to mention it is speculating about technology so far ahead of our own that it seems silly. 50's predictions of rocket belts and nuclear powered cars come to mind.
> 50's predictions of rocket belts and nuclear powered cars come to mind.
These are different kind of predictions. Rocket belts could work, but they don't make economic sense and there's a strong safety argument against it. It's the same reason we don't have flying cars either.
Nuclear-powered cars could have worked; the failure wasn't predicting technology or its feasibility, but that nobody figured out humanity will collectively go insane and irrationally refuse to develop use of nuclear energy.
Dyson spheres are a pretty obvious thing to do - every star is a free, self-maintaining fusion generator that just wastes almost 100% of its output. So the argument is really that when a civilization's need for energy gets larger than what can be supplied by burning whatever stuff they have on their planet, the next obvious step is their star. Barring some magic tech breakthroughs like pulling energy from "subspace" or whatever, you have a rather solid argument that's essentially: "as long as life is not limited from growing, it will eventually start blotting out the sun it orbits".
The 50s analogy is only to point out how we like to extrapolate contemporary technical understanding into the future. The envisioned dyson spheres I've seen look like our current understanding and use of photovoltaics extrapolated in the same way.
I don't disagree that the core idea of harnessing the suns energy seems likely. As the parent poster said, it's just the absolute confidence that people seem to have on the subject that's a bit curious.
Maybe breakthroughs in energy generation will make it not worth the effort? Maybe becoming interstellar makes it obsolete since the energy requirements for a given civilization are spread thinner? Maybe there are other ways to harness the solar energy that would not show the same signs as we predict? Maybe civilizations trend to energy efficiency instead of just increased usage?
Especially when the Earth is getting effectively zero of the sun's energy now, and humanity is so incapable of harnessing even that minuscule amount, that killing off their entire planet is still a much talked about possibility.
Such observation supposes that our timeline matches theirs (taking into account the delay due to lightspeed). We weren't capable of such observation until about a few decades ago, other civilization could have existed and vanished billions of years ago, or billions of years in the future, or are so distant that they're outside of our obserable universe (if they ever was within it).
Or energy is not such a big deal anymore once you've reached a certain stage of technological advancement, so it's not the right criteria.
Civilizations won’t go extinct once there are interstellar, thanks to the speed of light balkanizing any such civilization, and thereby providing redundancy.
I followed Tabby's Star news for a while (star that showed massive dips, speculation was that it is a dyson sphere being built).
Most scientists believe that even if the star is encased in Dyson sphere that there would be excess infrared emissions as the sphere would need to vent heat. It would be hotter than surrounding space and thus visible.
They are thus trying to detect such stars with higher mass and IR excess than expected, but so far there are not many candidates.
You cannot simply absorb all the energy of the star and never emit it. The waste heat has to go somewhere. An efficient Dyson sphere would still emit lower energy infrared radiation in a way that would be detectable from out space-based observatories.
One must assume either the aliens aren't there, or that the idea is not worth it for reasons we haven't discovered yet. Maybe planetside fusion power is just more efficient. Maybe they can harvest energy from black holes or something.
Because there's no other intelligent life out there.
You know that. But it bears mention, for others following along, that rampant artificial intelligence or similar does not count as a great filter candidate, because it would be just as visible as the life it's replacing.
That doesn't leave a lot of fast-acting filters that could still be in our future, to be honest. Nuclear war? Sure, but we've avoided it too long for that to be a good one either.
Artificial intelligence would necessarily have different physical needs than biological life. We can expect even our own AI to be a bit alien to our ways of thinking. Alien created AI would be completely alien to us. With different needs and different motivations, what evidence do we even look for, and if it is pervasive, how do we know we aren’t looking right at it?
It would still exist in the same universe subject to the same laws of thermodynamics, and would still extract energy from fusion stars in a way that leaves an unmistakable technology signature.
It would be subject to the same laws, barring novel physics (like extracting energy from dark matter or some other process we don't yet understand). But a single AI could be smarter than 10 billion humans and consume less energy, need less space, and not care about expanding out into the stars. They could coast around their host star indefinitely and when they eventually needed to leave (which could be never), they could store energy and make a long, slow trek to another star. Imagine trying to find an asteroid-sized object in interstellar space.
Our planetary system (formed 4.5B years ago) is comparatively late to the game. The waves from older civilizations should have been everywhere by now. If they were expansionist, they should have even collonised the whole Galaxy long ago.
If I remember the argument by Bostrom correctly, finding life would increase the probability that one or possibly a number of great filters are further up in the evolutionary development of life, as a corollary this would mean a higher likelihood that such filters still lie ahead of us.
Bostroms original article was about how finding intelligent life would be concerning. He even goes into detail about how a great filter could be somewhere in the evolutionary steps between simple life to complex, intelligent, civilization-building life.
My point is that the "omg great filter confirmed" is a bit premature, and is a misunderstanding of the argument.
EDIT: Re-reading your comment, maybe this isn't contradictory to your point. Finding out that there is an abundance of life does indeed eliminate at least one major candidate great filter. I'm not sure that would somehow move the odds of a real one being ahead of us though.
It's not about intelligent life per se; rather the more advanced life we find, the more concerning for the future it would be, as the likelihood of a great filter being located ahead of us increases, precisely because we haven't been able to detect more advanced life forms than us. Another interesting consideration is the Dark Forest, of course.
I dug out the section in Bostrom's paper:
"What has all this got to do with finding life on Mars? Consider the implications of discovering that life had evolved independently on Mars (or some other planet in our solar system). That discovery would suggest that the emergence of life is not a very improbable event. If it happened independently twice here in our own back yard, it must surely have happened millions times across the galaxy. This would mean that the Great Filter is less likely to occur in the early life of planets and is therefore more likely still to come.
If we discovered some very simple life forms on Mars in its soil or under the ice at the polar caps, it would show that the Great Filter must exist somewhere after that period in evolution. This would be disturbing, but we might still hope that the Great Filter was located in our past. If we discovered a more advanced life‐form, such as some kind of multi‐cellular organism, that would eliminate a much larger stretch of potential locations where the Great Filter could be. The effect would be to shift the probability more strongly to the hypothesis that the Great Filter is ahead of us, not behind us. And if we discovered the fossils of some very complex life form, such as of some vertebrate‐like creature, we would have to conclude that the probability is very great that the bulk of the Great Filter is ahead of us. Such a discovery would be a crushing blow. It would be by far the worst news ever printed on a newspaper cover."
Thank you for digging that up! It makes a lot of sense, Nick is a wise man. I still feel like it's incredibly hard to quantify just how much a difference a discovery like this (if it indeed turns out to be microbial life) would make.
It took evolution on earth four billion years to result in a single civilization-capable species. The potential of filters along the way seem incomprehensible. And four billion years is a meaningful timespan even in astronomical terms.
And the intelligence part is also like an elephant in the room. Even given vertebrate creatures with nervous systems, we've had those for hundreds of millions of years. The secret sauce for advanced civilization is still only possessed by a single species, and not even it understands how it happened. How do you map a transition like that on a linear timeline of filters?
There are many candidates for the Great Filter, in fact what you are proposing (it's unlikely to evolve civilization-level intelligence) is one of them.
If indeed abiotic processes couldn't have generated the phosphine and life does exist on Venus, some questions I'm pondering:
1) How can we determine whether Venusian and Terran life share a common ancestor? A seemingly clear signal would be a different genetic basis for Venusian life than DNA, but would the converse be true, or just a sign of convergent evolution?
2) How hard would it be to send a probe there that could perform a preliminary analysis of the life form? How hard would it be to bring a sample back to Earth?
3) This would be an indicator of life existing in the habitable zone of Venus' atmosphere. How should that change our estimate of the likelihood of other forms to exist on the surface of Venus? Earth extremophiles can exist at >100C, but the surface of Venus is >450C. On the other hand, there'd be a continuum which would allow evolutionary processes to work their magic. Acidity is also an issue, but the life forms in the habitable zone already be living at levels impossible for any known Earth species.
If the Venusian life has anything vaguely like replicating paired strands of nucleic acids, I think we have to assume a common ancestor (and I'd put my money on it coming from Venus). Even if there's no commonality whatsoever in details of the genetic code. FWIW, if we do discover life on Venus, I expect this to be the case.
Regarding #2, bringing a sample back to Earth is way too dangerous. At least, I'm certain NASA will see it that way, and I doubt any other space agency has the capability to execute a sample return mission within the next 10 years without NASA assistance.
If there is life on Venus, I am sure that priority #1 will be bringing it back to Earth. There are procedures and techniques with dealing with dangerous viruses, bacteria and such. If it is a bacteria that lives in an acidic oxygenless environment on Venus it is doubtful it could survive in an oxygen rich planet.
Perhaps a sample could be retrieved and kept in orbital cold-storage until we have the technology to do further analysis off-planet. In the meantime we can already do some analysis off-planet.
Danger for earth. When we introduce a species to a new environment, sometimes it dies, and sometimes it becomes an invasive species and kills a lot of other stuff. And some of those invasive species are big (like snakehead fish) and some are small (like the smallpox virus or, frankly, SARS-Cov-2). Many experts think there's a risk that an extraterrestrial microorganism could devastate some or all Earth life, given that no Earth life has had a chance to evolve defenses against it.
We know how to manage risk - we can process the sample on the space station if needs be. The issue here is probably contamination of the Venusian atmosphere.
2) Russia already launched a balloon equipped mission to Venus. There are ideas for a new NASA mission with a balloon. If this discovery resists abiotic explanations, this type of mission will receive a massive priority boost. Sending a probe for preliminary analysis seems relatively straight forward, what is harder is to designs systems that would operate long enough in an acidic environment to get resuls. Return to Earth is also hard as Venus has gravity comparable to Earth but with enough funding I am sure it is possible.
3) What is more interesting to me is if there is bacterial life on Venus, is there anything more complicated?
Ok. I am hyped. I had always been fairly obsessed with Venus and any news about possible biological processes there (though very unlikely) is welcome to my nerdy ears.
Venus has a zone above the clouds where the atmosphere is not that cruel and the temperature livable. There is always the chance of airborne microorganisms living in the oasis layer above the hell that is the near-surface of Venus.
> Venus has a zone above the clouds where the atmosphere is not that cruel and the temperature livable. There is always the chance of airborne microorganisms living in the oasis layer above the hell that is the near-surface of Venus.
Just to add to this, it's a similar temperature and pressure to earth, but the main gas is CO2. In other words, almost ideal for anaerobic organisms (bar the absence of water), which are the kind that generate phosphene, i.e. the biosignature that was detected.
What's the confidence level that the detection of phosphine is not some sort of false positive? I read the majority of the google cache and that aspect seemed to be glossed over.
They used two different observatories (James Clerk Maxwell Telescope and the Atacama Large Millimeter Array) to confirm the signal. The chances of both being wrong in the exact same way is very low.
The video explainer linked from the EarthSky article mentioned this, clarifying that there's no known natural and abiotic means of producing phosphine on rocky planets. Apparently gas giants can crank out phosphine without it being indicative of life.
The video says phosphine is also produced at hellish pressures in the depths of planets like Jupiter. So how likely is it that it is produced at hellish depths in Venus and then spat out into the atmosphere by active volcanism?
Venus is a rocky planet, it doesn't have hellish depths like a gas giant does. The researches have no credible explanation how those quantities of phosphine can be produced on a rocky planet.
Venus has extreme heat and pressure at its surface. The temperature is around 500C, and the pressure is nearly 100 Bar (about the pressure at 3000ft depth). That is indeed hellish, and this is indeed a good question.
Depends on your definition of hellish. I guess Venus could be called that but it is not comparable to the pressures and temperatures that are found inside gas giants. For example Jupiter is estimated at 24000 Celsius at the core with pressures of several million bar. This is vastly different than environment on Venus and that is why they have no credible abiotic explanation for phosphine generation on Venus.
My point was that Venus is not comparable to a gas giant.
> Research scientists […] submitted a paper to the peer-reviewed academic journal Astrology […]
Someone might want to very quickly correct that to "Astrobiology". This whole presentation, of going from a tweet to a Quora Q&A obviously posted by the same person, is a bit weird.
And a very weird Quora at that. They posits that gravity waves keep these organisms in the atmosphere. And then goes on to mention that viruses that cause disease may be coming from space.
Hard to imagine a civilization advanced enough to trigger a runaway greenhouse effect and yet not having achieved a space program with all that energy usage.
EDIT: Venesian satellites would have been detected, if that's not clear.
It’s be quite a bit easier to trigger a runaway greenhouse effect at 0.74 AU.
In addition, besides needing a boost to maintain orbit (solar panels that function for 750 million years?) some forces have acted to slow and reverse Venus’ rotation and it is hard to imagine satellites wouldn’t be significantly affected over long time scales.
A space program isn’t necessarily a natural consequence of CO2 production anyway. That might be especially true for creatures who don’t have the benefit of a moon.
After 750 million years? I doubt any of ours will be detectable after that time, at least not without a very careful search (which hasn’t been done for speculative Venusian ones).
I’d also assume that if a Venusian civilization was capable of releasing satellites, they also likely generated an abundance of space junk which, over the course of hundreds of millions of years, would completely tear apart any trace of these satellites.
Assuming no abiotic pathway is found, what type of mission will confirm Venusian life? I imagine that everyone will agree it's way too dangerous to bring a sample back to Earth for analysis, so I expect we'll need to send microscopes to Venus. We'll also need to send something down into the appropriate cloud layer to collect a sample. Keeping anything aloft in the atmosphere will be expensive, so I assume that they'll separate those two elements of the mission, Apollo-style. So I expect that they'll send an orbiter containing the microscopes, and then a glider that collects the sample and then fires an engine to get out of the atmosphere and rendezvous with the orbiter (a helicopter would also be possible, but I expect it will be easier to get a plane back out of the atmosphere than to launch some kind of ascent vehicle from a helicopter). If they can design the sample capture mission to preserve the atmospheric pressure, temperature, etc. they might be able to get it up for analysis with the organisms still alive.
I mean, people come and go to labs holding _smallpox_. I would assume the main risk of bringing back to earth would be landing failure, but just having the thing in a room doesn't seem like a huge risk compared with what certain labs already deal with.
Been following this topic for a little bit now, and one thing I don't see being discussed very often is the possibility that the phosphine gas is being created by bacteria or microbes of terrestrial origin.
I.e. who's to say that the lander that made planetfall a while ago wasn't contaminated with a hardy strain of bacteria?
Before we get too excited, we already know phosphine is in Jupiter's atmosphere, and Jupiter is an awfully unlikely candidate for life. So the claim that it can only be produced in the lab and by microbes strikes me as already implausible, even if we don't know exactly why there's phosphine in Jupiter's atmosphere.
https://en.m.wikipedia.org/wiki/Atmosphere_of_Jupiter#CITERE...
https://arxiv.org/ftp/arxiv/papers/1910/1910.05224.pdf talks at length about it -- the result is known to be wildly invalid for gas giants, as they have the temperatures and pressures to have viable chemical pathways to phosphene.
Yeah - the argument in the paper is a lot more nuanced than it's being represented in the media, where it's being flattened to the point of uselessness.
It would be hilarious if we've been wondering why we're alone in the universe all this time just to find out we're not even the only planet in our solar system to support life.
We know that tardigrades can survive in space and that there are Martian rocks sprinkled over the Earth. Perhaps there were some microbes blasted into Venutian orbit when the Chicxulub meteor took out the dinosaurs 66 million years ago?
Doing a sample recovery from Mars's surface is very hard at this point. It should be much easier to do a sample recovery from Venus's high atmosphere, shouldn't it? Is there anything planned to that effect?
I'm not an astrophysist nor biochemist, so i'm sorry if this is a dumb question, but how likely is it that we "contaminated" Venus with earth's microbiology embedded in our previous probes ?
They collect light, split it into its colors and check for certain colors being more or less present or absent. This is a so called spectrum and different atoms, ions and molecules have a characteristic pattern there.
I'm sure it has been checked. This effect is not strong and they probably needed to "aim" for a specific part of Venus. Also newer telescopes and data analysis methods may be able to see the effect when before it would be lost in the noise.
"This was an experiment made out of pure curiosity, really, taking advantage of JCMT’s powerful technology, and thinking about future instruments. I thought we’d just be able to rule out extreme scenarios, like the clouds being stuffed full of organisms. When we got the first hints of phosphine in Venus’ spectrum, it was a shock!"
It's possible! But there's been been many instances of material exchange between the inner rocky worlds that could have seeded life on any or all of them. Either way, seeing evidence of flourishing biota on other worlds, be they local extremophiles or alien life, is exciting
I shared this with my girlfriend, and she, without being phased even slightly, replied, “Can I tell you a secret? I’ve always known that Venus is alive.”
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.