Evidence detected for life in the clouds of Venus
September 14, 2020 8:05 AM   Subscribe

 
Live: Royal Astronomical Society announcement (Youtube stream of Zoom press briefing)
posted by Major Clanger at 8:06 AM on September 14


Very interesting finding, but the "artist's impression" is cracking me up.
posted by me3dia at 8:21 AM on September 14 [19 favorites]


Summary of key points so far:

- very clear evidence of phosphine, detected at submillimetre wavelengths
- phosphine is seen in latitudes corresponding to Venus' Hadley circulation cells
- concentration is about 20 parts per billion
- this is low, but hundreds of thousands of times higher than any known mechanism should result in, as determined by extensive modelling
- so, this is either unknown chemistry, or the product of biological activity
- the environment in the upper Venusian atmosphere is hostile, but bacterial life is not impossible
posted by Major Clanger at 8:22 AM on September 14 [35 favorites]


!
posted by Reclusive Novelist Thomas Pynchon at 8:27 AM on September 14


Whoa. Huge. !
posted by tiny frying pan at 8:29 AM on September 14


Q&A begins

Prof Chris Lintott (Oxford University, BBC Sky at Night presenter): (1) The Nature paper was meant to be open-access, it isn't yet, please fix this! (2) How confident are we about the calculation of natural production for phospine?
Dr William Bains: Hugely complex, but all calculations come out with far lower amounts than we see.
posted by Major Clanger at 8:31 AM on September 14


From an astrobiologist friend I asked him about this......(he wrote a textbook!)

"My take? Not betting on it being life. There has, as the article noted, long been speculation that life could have arisen prior to Venus losing all its water (via photolysis and the resulting escape of H into space), which in turn would have caused its current runaway greenhouse (Earth has the same amount of CO2, but here, because we have oceans, it all gets locked up in sedimentary rocks).

And maybe if life arose on the surface, it could have survived in niches in the clouds. I'm not optimistic about either of those ideas, but they're not impossible. Now, on to phosphine. Phosphine on Earth is produced by anaerobic microbes, true. They produce it when they use inorganic phosphate as their electron sink. I.e., they pick up electrons from the environment (from decayed plant material, or perhaps from geology) and then dump them onto phosphate to make phosphine and eak out a tiny bit of energy. And there is P4O6 in the venusian clouds (the Vega probes detected it).

But there's no reducing potential in the Venusian atmosphere, so the biological phosphine-generating reaction we see on Earth makes no sense on Venus -the reduction of phosphate to phosphine does not provide energy there. Now, the bugs could use photosynthesis to pull electrons from water and donate them to P4O6 to make phosphine, but at that point, why then the bugs would just use CO2 as their electron acceptor since, presumably, they need reduced carbon and not reduced phosphorous to make more of themselves?

So, the reason phosphine is produced by some rare, niche life on Earth doesn't hold on Venus. Thus I'm betting "we don't know all that much about the planetary scale atmospheric chemistry/geochemistry that happens at 500C in the absence of water and oxygen" is the answer rather than "life.""
posted by lalochezia at 8:32 AM on September 14 [101 favorites]


Q: How long does phosphine last in Venus' atmosphere?
Dr William Bains: in cloud tops, 'thousands of seconds', lower down, longer. Depends on details of atmospheric chemistry not yet well understood. But unlikely to be a sporadic process, rather an equilibrium.
posted by Major Clanger at 8:33 AM on September 14 [1 favorite]


Here's a direct link to the paper.

mm-wave astronomy can be done with small telescopes - as in one you can build on your rooftop. I'm not sure about atmospheric disturbance at these wavelengths but it wasn't a problem for the 2.6mm observed with the Mini, which is in Boston and used to be in NYC.
posted by vacapinta at 8:34 AM on September 14 [3 favorites]


Q: (Didn't catch name, from Planetary Society): What sort of space mission would you like to see?
Prof Sara Seager: Lots! Mass spectrometer would be good. A microscope even, but will be difficult. A balloon mission (like the Soviet VEGA missions in the 1980s) would be a good idea, but aiming to last weeks rather than days.
posted by Major Clanger at 8:35 AM on September 14 [1 favorite]


I'm delighted and hope this spurs additional exploration of our less-popular orbital neighbor, Venus. What a wonderful discovery to wake up to today! This is why I love Metafilter: sometimes, it gives me a rush of hope I didn't even know I needed.
posted by Unicorn on the cob at 8:40 AM on September 14 [4 favorites]


Financial Times science correspondent: what biomass of microbes would be needed to account for the amount of phosphine seen?
Dr William Bains: so sensitive to assumptions it's hard to say. Any calculation working with Earth equivalents would be subject to vast numbers of differences. But concedes that it won't be "a tiny patch", it would be very widespread. Need more data on distribution of gas.
posted by Major Clanger at 8:40 AM on September 14 [2 favorites]


vacapinta, thanks for the link!

Over on Twitter, Nature's astronomy editor blames technical issues, Chris Lintott is rather grumpy, pointing out they had a month's notice! (via embargoed advance briefing)
posted by Major Clanger at 8:44 AM on September 14 [2 favorites]


I've only just finished book 2 of The Expanse, can someone please put a spoiler tag on the universe?
posted by phunniemee at 8:53 AM on September 14 [13 favorites]


Did Scientists Just Find Life on Venus? Here's How to Interpret the Phosphine Discovery from the Planetary Society.

Bottom line: compelling finds, looks promising and the scientists were careful by doing separate observations at separate times, but it's not a slam dunk. Definitely worth investigating further!

It would be very 2020 to find that yes, there's life in hell.
posted by Brandon Blatcher at 8:55 AM on September 14 [21 favorites]


We scanned the skies with rainbow eyes and saw machines of every shape and size.
We talked with tall Venusians passing through.
And Peter tried to climb aboard but the Captain shook his head
And away they soared,
Climbing through the ivory vibrant cloud.


still miss him
posted by jquinby at 8:59 AM on September 14 [7 favorites]


Q: (Didn't catch name, from Planetary Society)

Mat Kaplan.
posted by zamboni at 8:59 AM on September 14


...someone passed some bliss among the crowd

super interesting!
posted by 20 year lurk at 9:06 AM on September 14 [1 favorite]


We've sent so many things to Mars, some of them even get there.

In the later phases of the Apollo Program, there was even a theoretical "What if we sent a crew to Venus" mission. Manned Venus Flyby. We'll never the get the jungles and oceans of old SF, like in Kuttner's "Clash by Night," but it would be great if we sent a few more probes to our clouded neighbor.
posted by fifteen schnitzengruben is my limit at 9:12 AM on September 14 [1 favorite]


Thus I'm betting "we don't know all that much about the planetary scale atmospheric chemistry/geochemistry that happens at 500C in the absence of water and oxygen" is the answer rather than "life.""

You're probably right, but 2020 has been such shit it would be nice to get something good this year like confirmation of non-Earth life.
posted by star gentle uterus at 9:16 AM on September 14 [3 favorites]


Also, NASA has studied the idea of establishing colony among the clouds of Venus. It would almost be Earth like, watch the video!
posted by Brandon Blatcher at 9:19 AM on September 14 [4 favorites]


Don't worry, everybody, I'm confident that Space Force® is already diverting resources from their blow-up-the-moon initiative, and pivoting to an armed assault on the Venusian menace.

Where's there's prehistoric evidence of life, there's gotta be oil, right?
posted by Mayor West at 9:23 AM on September 14 [5 favorites]


Do they have antennae? How many legs?
Just bacteria? BORING. Back to the writer's room, you mugs.
Or, wait, could the bacteria ride spacecraft back to earth and kill us all? No? Yeah, back at it then and get cracking! We have standards to uphold here!
posted by From Bklyn at 9:28 AM on September 14 [1 favorite]


My bet also is that this is us not understanding the chemistry of Venus's atmosphere.

But it also highlights the fact that NASA has been pretty chicken about Venus, giving Venus exploration short shrift for a long time. Hopefully this will prod NASA HQ to change on that.
posted by tclark at 9:28 AM on September 14 [5 favorites]


Obligatory timely SMBC
posted by sauril at 9:28 AM on September 14 [4 favorites]


It would be very 2020 to find that yes, there's life in hell.

FWIW I'm not sure that the thick and sulfurous atmosphere of Venus is all THAT much more hostile to life than, say, the Marianas Trench or Everest. We've seen evidence in our own back yard of some pretty complex organisms living in conditions that we never thought it possible for even microbial life to survive in.

Life, uh, finds a way. Fingers crossed that this is more than hitherto-unknown atmospheric chemistry!
posted by Mayor West at 9:29 AM on September 14


Out of curiosity, would the microbes that produced the phosphine be ... well ... edible? Especially if deep-fried, or accompanied by a nice cheese sauce? And what would they taste like? #ShouldIEatIt

Asking for a friend.
posted by Wordshore at 9:29 AM on September 14 [14 favorites]


Excuse my ignorance, but what exactly would be the mechanism that keeps these “bacteria” up in the air where it’s cooler. And no, I don’t expect them to have wings.
posted by njohnson23 at 9:38 AM on September 14


Out of curiosity, would the microbes that produced the phosphine be ... well ... edible

I mean, ANYTHING is edible if you're stubborn enough. Phosphine-producing organisms are usually bacteria breaking down organic matter, but we don't know exactly what the exobiology of these particular ones are like. At the least, I bet they'd make an interesting addition to a fermentation process--Venusian sauerkraut or a wheel of Yellow Planet Leicester, anyone?
posted by Mayor West at 9:40 AM on September 14 [4 favorites]


The chances of anything coming from Venus are a million to one...
posted by Damienmce at 9:47 AM on September 14 [3 favorites]


* Solaris sentient ocean .gif *
posted by Beardman at 9:54 AM on September 14 [8 favorites]


OMG I needed hearing a scientific announcement. Hearing people talking intelligently about things we both know and don't know, considering possibilities, and being guided by facts. A refreshing break from politics!
posted by mazola at 9:57 AM on September 14 [14 favorites]


Two hypotheses:

1) Life is present on a planet with no hydrogen
2) We don't know enough about phosphine chemistry under Venusian conditions

The default mode of science reporting is "Exobiology of the gaps" -- golly gee, we don't know how this came to be, therefore maybe life!

I am one of those wackos who think most planets with decent entropic gradients and some type of polymers have life (even if with chemistry we cannot currently understand), but this is pretty thin gruel.
posted by benzenedream at 9:58 AM on September 14 [5 favorites]




#ShouldIEatIt

during the presser's q&a, circa 48:00, dr. william bains noted that terrestrial scientists are not certain which microbes produce phosphine. this is repeated by prof. sara seager, circa 56:00, who notes that "it looks like it's some kind of strain of e. coli...," and that biologists "don't know the exact biochemical pathway" that makes it.
posted by 20 year lurk at 10:19 AM on September 14 [1 favorite]


"it looks like it's some kind of strain of e. coli..."

So, uh, promising? Which wine does 'e. coli' pair with?
posted by Wordshore at 10:21 AM on September 14 [4 favorites]


We're heading for Venus (Venus)
And still we stand tall
'Cause maybe they've seen us (seen us)
And welcome us all, yeah
With so many light years to go
And things to be found (to be found)
I'm sure that we'll all miss her so
It's the final countdown

posted by Halloween Jack at 10:23 AM on September 14 [3 favorites]


Excuse my ignorance, but what exactly would be the mechanism that keeps these “bacteria” up in the air where it’s cooler. And no, I don’t expect them to have wings.

They're very small. In our atmosphere, microbes are stuck to particulates or in/on water droplets. We can assume, if they exist, that the same could be true in the atmosphere of Venus, just with different particulates and droplets than ours.
posted by hydropsyche at 10:37 AM on September 14 [2 favorites]


And I realize that was very unclear. Very small things fall very slowly, so bacteria can just float in the air on wind currents, as well as being stuck to things.
posted by hydropsyche at 10:43 AM on September 14 [3 favorites]


Wrinkled Stumpskin, that bit stuck out to me, too. Bit of charming mundane humanity in the big astrobio.

njohnson23, here's the research paper by Greaves et al that should help explain the proposed process. From the abstract:

We argue that life must reside inside liquid droplets such that it will be protected from a fatal net loss of liquid to the atmosphere, an unavoidable problem for any free-floating microbial life forms. However, the droplet habitat poses a lifetime limitation: Droplets inexorably grow (over a few months) to large enough sizes that are forced by gravity to settle downward to hotter, uninhabitable layers of the Venusian atmosphere. (Droplet fragmentation—which would reduce particle size—does not occur in Venusian atmosphere conditions.) We propose for the first time that the only way life can survive indefinitely is with a life cycle that involves microbial life drying out as liquid droplets evaporate during settling, with the small desiccated “spores” halting at, and partially populating, the Venus atmosphere stagnant lower haze layer (33–48 km altitude). We, thus, call the Venusian lower haze layer a “depot” for desiccated microbial life.
posted by Lonnrot at 10:44 AM on September 14 [7 favorites]


Also I just noticed who made this post and laughed.
posted by Lonnrot at 10:47 AM on September 14


Venusian

Venerian, surely?
posted by maxwelton at 10:51 AM on September 14 [2 favorites]


Venus has no protective magnetic field, unless I misremember. What is keeping life in the upper atmosphere from getting fried by the sun?
posted by They sucked his brains out! at 11:12 AM on September 14 [1 favorite]


the environment in the upper Venusian atmosphere is hostile, but

This is always something that has always really confused me - this idea that OF COURSE the search for life in the universe equals the search for Earth-like environments. Except Earth has gone through many well-populated geological periods in which basically all current Earth life would die instantly, and also Earth has organisms that live in volcanic vents or under glaciers or that eat rocks or etc etc.

I get that if you're doing a broad search, you want to narrow the field to Earth-like planets. But is the atmosphere of Venus actually "hostile to life" in a truly objective sense, or is it just that it's hostile to cuddly human-and-human-adjacent forms of life, so we write it off as "just plain hostile to life" without considering that maybe OUR planet looks just as hostile from a Venusian perspective?
posted by showbiz_liz at 11:13 AM on September 14 [5 favorites]


We regret to inform you the Venusian life is racist
posted by stevis23 at 11:15 AM on September 14 [25 favorites]


If life really does exist on Venus, seems like humanity's first order of business should be finding a way to warn them about us.
posted by DirtyOldTown at 11:19 AM on September 14 [2 favorites]


Venusian

Venerian, surely?

But not venereal.
posted by bassomatic at 11:22 AM on September 14 [1 favorite]


Venus barely has any water. You need a solvent for life (probably water, but maybe something else) that looks anything like terrestrial life. There isn't a lot of any obvious solvent on Venus other than a little bit of water vapor in the atmosphere. So, any life on Venus is either analogous to Earth bacteria or something so deeply strange that we have no frame of reference.
posted by BungaDunga at 11:23 AM on September 14 [1 favorite]


We regret to inform you the Venusian life is racist

Domainist, surely
posted by OHenryPacey at 11:23 AM on September 14 [2 favorites]




sauril: "Obligatory timely SMBC"
Did Zach Wienersmith have this in the drawer or does he come from the future?
posted by andycyca at 11:39 AM on September 14 [2 favorites]


The chances of anything coming from Venus are a million to one...

Men are from Mars Women are from V... waitaminnute... o_0
posted by Devils Rancher at 11:48 AM on September 14 [1 favorite]




So, uh, promising? Which wine does 'e. coli' pair with?

I'm not sure, but you buy it by the butt.
posted by kirkaracha at 12:10 PM on September 14 [3 favorites]


Venus is a hoax. /s
posted by Freedomboy at 12:23 PM on September 14 [2 favorites]


Did Zach Wienersmith have this in the drawer or does he come from the future?

Rumors about this leaked yesterday, so he had almost a full day for drawing
posted by ymgve at 12:25 PM on September 14 [1 favorite]


Um, unknown chemistry on another planet seems way, way easier to believe than microbes on a world without water.
posted by medusa at 12:26 PM on September 14 [4 favorites]


I sure want this to be life, but medusa summarized my thoughts on this announcement. Cool stuff, though!
posted by haiku warrior at 12:38 PM on September 14 [1 favorite]


This is always something that has always really confused me - this idea that OF COURSE the search for life in the universe equals the search for Earth-like environments. Except Earth has gone through many well-populated geological periods in which basically all current Earth life would die instantly, and also Earth has organisms that live in volcanic vents or under glaciers or that eat rocks or etc etc.

Astrobiologists get this question a lot! One part of the answer is that the search for life does indeed include life that lives on volcanic vents, under miles of ice, and so on. There's a great deal of interest in the oceans of Europa, for instance. The thing all these environments still have in common is liquid water; the search for life is in part a search for liquid water, because all life-as-we-know-it requires water.

So why aren't we looking for life-as-we-DON'T-know-it, then? Well...because we don't know it. It's hard enough to figure out reliable chemical signals that would indicate the presence of water-requiring, carbon-based, Earth-type lifeforms. If we don't know anything about the chemistry or preferred habitat of the life we're looking for, we can't narrow down the search at all. And resources are limited, so we prioritize looking for environments where we know life can exist and we have a better chance of recognizing it if we see it. Looking for life-as-we-know-it is like looking for a needle in a haystack; looking for life-as-we-don't-know-it is like looking through a field full of haystacks for something whose properties you don't know (could it be a plastic straw? a soap bubble? a magnetic field? a differently-colored piece of hay?) and that you might not even recognize if you found it.

Don't get me wrong, though--any finding that can't immediately be explained by known natural processes is going to make the scientific community sit up and take notice, as we can see in this article. I think most astrobiologists are open to the possibility of life-as-we-don't-know-it, it's just much harder to look for.
posted by fermion at 12:47 PM on September 14 [27 favorites]


I think most astrobiologists are open to the possibility of life-as-we-don't-know-it, it's just much harder to look for.

Have you tried driving a giant spaceship around to see if anything tries to kill you, mate with your ship or take over your holodeck? That seems to work well for discovering hitherto unknown forms of life.
posted by jacquilynne at 1:04 PM on September 14 [11 favorites]


Not to mention the 100% chance that your ship will spontaneously generate its own intelligence, or your interstellar probe come back with some very unusual ideas...
posted by BungaDunga at 1:06 PM on September 14 [1 favorite]


Ugly bags of mostly water stay out of Venus atmosphere. Come back in 300 years.
posted by polecat at 1:09 PM on September 14 [6 favorites]


Hey, I got a hair cut.
posted by Brandon Blatcher at 1:18 PM on September 14 [1 favorite]


This is helping bolster my theory that Mars was set up to serve as a distraction, to keep us away from Venus.
posted by senor biggles at 1:32 PM on September 14 [1 favorite]


I just want to share cnn.com's difficult to parse headline for this:

Gas found on Earth that signifies life has been found on Venus

We found a gas on Earth and it signifies life has been found on Venus?
posted by He Is Only The Imposter at 1:41 PM on September 14 [15 favorites]


You're probably right, but 2020 has been such shit it would be nice to get something good this year like confirmation of non-Earth life.

I think your grimmer alien invasion tales are the ones most on brand for a 2020 confirmation of extraterrestrial life.
posted by ricochet biscuit at 1:43 PM on September 14


PROTOMOLECULE LINKED TO EROS CRASH BLOSSOMS
posted by polytope subirb enby-of-piano-dice at 1:44 PM on September 14 [8 favorites]


I just want to share cnn.com's difficult to parse headline for this:
Gas found on Earth that signifies life has been found on Venus


Odorless Gas Found On Lifeless Planet
posted by Atom Eyes at 1:53 PM on September 14 [1 favorite]


At the very least, this seems like a really good reason to put a millimeter wave telescope into orbit around Venus. I would assume that doing the same measurements from Venusian orbit, instead of from ~1 AU away, would let us map the amount of phosphine and other substances in much finer detail, not to mention looking for diurnal and seasonal changes.

That still wouldn't definitively resolve the question of whether or not it's a sign of life, but it would sure be interesting to see, and it would be a lot easier than trying to collect atmospheric samples.

(I see that the proposed Russian Venera-D mission is supposed to have a millimeter wave radiometer, but Wikipedia seems to indicate it can only measure up to the W band, which isn't quite high enough frequency for this. Bummer.)
posted by teraflop at 2:18 PM on September 14 [1 favorite]


Are we sure that this isn't some crazy evolution of life forms that took a ride on Venera? As far as I know several Venera landers are still there on Venus.
posted by vacapinta at 2:23 PM on September 14 [3 favorites]


Meanwhile, on Venus, there's just been a big announcement by a group of scientists claiming that even though they have spotted evidence of bilious hot guff collected over select bits of the faraway planet Terra, it's no proof there's intelligent life on that rock.
posted by chavenet at 2:26 PM on September 14 [1 favorite]


I hadn't noticed this thread until now. Being we're talking about life on Venus, I did the ctrl+F for "protomolecule" and MeFi did not let me down. Slow hand clap for polytope subirb enby-of-piano-dice
posted by Ber at 2:36 PM on September 14 [1 favorite]


I was only looking for a David Bowie reference, and MeFi did not let me down either.
posted by The Nutmeg of Consolation at 2:42 PM on September 14


The obligatory XKCD came out on the same day!
posted by signal at 3:37 PM on September 14 [1 favorite]


Pretty sure “I Am the Doorway” involved a Venus flyby. So that’s promising.
posted by Mister Moofoo at 3:51 PM on September 14 [1 favorite]


If you can access the Sky at Night then definitely do. It’s great journalism about it and brings out the human elements of the story delightfully.

I’m the wrong kind of astronomer (not least by being somewhat out of the business) but colleagues broadly all seem to be delighted by the result but cautious of the interpretation. Whatever the explanation it’s likely to be new and fascinating. And regardless I love the tale of a long shot paying off.
posted by edd at 3:58 PM on September 14 [2 favorites]


The press releases say the authors tried to rule out known abiotic processes, but why didn't they consult with theoretical chemists who are better equipped to speculate on unknown, non-earthly, abiotic processes as well? It would reduce the skepticism around the argument that Venus has life forms responsible for the amount of phosphene being produced.
posted by polymodus at 5:20 PM on September 14 [2 favorites]


Consulting with chemical experts who are likely to shoot down your very buzzworthy press release is unfortunately rare these days. See also: arsenate DNA
posted by benzenedream at 6:40 PM on September 14 [1 favorite]


According to an AP account, the whole thing started when three astronomers walked into a bar ...
posted by adamg at 7:25 PM on September 14 [1 favorite]


An MIT-affiliated scientist quoted in the longform article I read was described as having dedicated her decades of research to phosphene in all its forms, it’s not like they didn’t talk to a chemist lol
posted by sixswitch at 9:14 PM on September 14 [4 favorites]


Mr Moofoo: Are there eyeballs between your fingers? Are you sure?
posted by sixswitch at 9:15 PM on September 14 [1 favorite]


Several commenters have written phosphene, which is an optical phenomenon, when they mean the chemical phosphine.
posted by haiku warrior at 9:38 PM on September 14 [3 favorites]


That's completely not the point. The point is, their primary argument consists of a double argument: a) Observations and conditions don't match any existing known processes for generation of phosphine, b) Therefore, either b1) There is some novel abiotic process, or b2) There is some biological process on Venus, responsible for measured levels of phosphine.

The way to deconstruct this argument is to address b1) using the searchlight fallacy. The way to do that is to answer the question, "Are there chemically exotic processes as opposed to extant, known processes on Earth and/or the Gas Giants, that are not known to exist but could theoretically serve as the pathways in synthesis of phosphine?". I.e., that some reasonable effort was spent to mitigate unknown-unknowns. It doesn't matter at all if the author herself is a theoretical chemist or not, the question that needs to be articulated, but was not, asked as a part of the argument is not there. A key part of scientific inquiry, and science communication as well, is to structure one's arguments and questions against possible criticisms of the discovery or its implications. Ultimately this has nothing to do with the expert (= appeal to authority/expertise), but how the idea is logically presented.
posted by polymodus at 9:40 PM on September 14 [2 favorites]


The Nature Astronomy article reporting the results was quite clear that the presence of phosphine in the atmosphere Venus needed more investigation before concluding that living organisms were the source of it.

Even if confirmed, we emphasize that the detection of PH3 is not robust evidence for life, only for anomalous and unexplained chemistry. There are substantial conceptual problems for the idea of life in Venus’s clouds—the environment is extremely dehydrating as well as hyperacidic. However, we have ruled out many chemical routes to PH3, with the most likely ones falling short by four to eight orders of magnitude (Extended Data Fig. 10). To further discriminate between unknown photochemical and/or geological processes as the source of Venusian PH3, or to determine whether there is life in the clouds of Venus, substantial modelling and experimentation will be important. Ultimately, a solution could come from revisiting Venus for in situ measurements or aerosol return.

posted by haiku warrior at 9:55 PM on September 14 [2 favorites]


That was actually the paragraph that prompted my question, because it is emphasizing life in the clouds so much that it effectively de-emphasizes the need for what they merely call "modelling" and what I call returning to theory and chemical principles. Note the second to last sentences is basically saying, we need to discriminate between two unknown-unknowns. Something about that position feels odd to me.
posted by polymodus at 10:09 PM on September 14 [4 favorites]


I, for one, welcome our Venusian microbial overlords.
posted by The Underpants Monster at 12:54 AM on September 15 [1 favorite]


polymodus, they did consider it other sources, and did chemical modeling to find other ways phosphine could have been created:
Potential PH3-production pathways in the Venusian environment are discussed in detail in the Supplementary Information (W. Bains et al., manuscript in preparation; summarized in Extended Data Fig. 10). Two possible classes of routes for the production of PH3 were considered: photochemical production or non-photochemical chemistry. For photochemical modelling, we created a network of reactions of known kinetic parameters59 that could lead from H3PO4 (phosphoric acid) to PH3 (phosphine), by reaction with photochemically generated radicals in the Venusian atmosphere. Where reactions were possible but no kinetic data for the phosphorus species were known, homologous nitrogen species reaction kinetics were used instead, validated by comparing reactions of analogous nitrogen and phosphorus species. The maximum possible rate for reductive chemistry in this network was compared with the destruction rate as a function of altitude. Non-photochemical reactions were modelled thermodynamically. For surface and atmospheric chemistry, we created a list of chemicals, their concentrations and reactions, for all potential PH3 production reactions. Phosphorus species abundances were calculated themodynamically and assumed to be in equilibrium with liquid/solid species at the cloud base. The free energy of reaction, indicating whether the net production of PH3 was thermodynamically favoured, was calculated using standard methods (see Supplementary Information for details). None of the reactions favour the formation of PH3, on average having a free energy of reaction of +100 kJmol−1 (Extended Data Fig. 7)
posted by ymgve at 5:47 AM on September 15 [3 favorites]


Follow-up to my previous comment:: it turns out that the BepiColombo probe is only a few weeks away from a flyby of Venus (on its way to a rendezvous with Mercury in 2025) and it's carrying an infrared spectrometer that might possibly be capable of looking for phosphine.
posted by teraflop at 4:00 PM on September 16 [1 favorite]


polymodus, they did consider it other sources, and did chemical modeling

Yeah but I totally already mentioned this in the first sentence of my first comment. My question is if you are doing a study and are trying to explain this mystery gas, then how comprehensive does the abiotic theorizing part need to be, balanced against the leap to a suggestion that an alien life form is making it. It's that balancing, of a two-pronged argument, and the context of the general reaction of outside experts, many of who have voiced that it probably isn't aliens, that begs questioning. That is a critical reading of how this news cycle is playing out, independent of the details dug out of the papers.
posted by polymodus at 10:00 PM on September 19 [1 favorite]


Right now there's an interesting little article on the Science magazine press release blog EurekAlert! about extremophiles, particularly those very resistant to radiation, which I think shines an albeit very oblique light on the question of existence of life on Venus.

Because it turns out to be hard to come up with contemporary Earth habitats which require this huge resistance to ionizing radiation:
The toughest organisms on Earth, called extremophiles, can survive extreme conditions like extreme dryness (desiccation), extreme cold, space vacuum, acid, or even high-level radiation. So far, the toughest of all seems to be the bacterium Deinococcus radiodurans - able to survive doses of radiation a thousand times greater than those fatal to humans. But to this date, scientists remained puzzled by how radio-resistance could have evolved in several organisms on our planet, naturally protected from solar radiation by its magnetic field. While some scientists suggest that radio-resistance in extremophile organisms could have evolved along with other kinds of resistance, such as resistance to desiccation, a question remained: which genes are specifically involved in radio-resistance?
It struck me on the one hand that the highest reaches of the Earth's atmosphere, which parallel those of Venus in terms of solar wind radiation exposure though the exposure would be significantly less because of Earth's stronger magnetic field, might be a habitat which rewards radiation resistance, and Deinococcus radiodurans might be an emigrant from there, and that makes bacterial life on Venus seem more likely. And on the other, the problem of the existence of D. radiodurans would vanish if it had recently been blown here from somewhere else by the solar wind, 'somewhere else' most likely being Venus.
posted by jamjam at 10:29 PM on September 21


D. radiodurans is not from another planet unless all bacterial life is, since it is very easily placed in a large bacterial taxonomy. It has many relatives not all of which are extremophiles. If D. radiodurans did not use DNA or regular proteins like the rest of Earth-evolved life, that would argue it was an exobacteria. This is not the case. Last I heard the natural reasons for high radiation tolerance were either living in radioactive hot springs, or baking on rocks in the sun and absorbing a huge amount of UV DNA damage.
posted by benzenedream at 11:07 PM on September 21 [2 favorites]


Well, since you mention all bacterial life, Venus does have the most circular of all planetary orbits, and a quite small inclination of its rotational axis, which would almost seem to guarantee it didn't suffer a huge collision with a Mars-sized and presumably planet sterilizing body (Theia), the way Earth did 4.5+ billion years ago, and that might have given it at least hundreds of millions of years of head start in the development of life in the first place, which has seemed ever more surprisingly rapid here on Earth as the date of the first appearance of life has been pushed relentlessly back toward the arrival of Theia over the last 20 years.
posted by jamjam at 11:39 PM on September 21


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