This is a part of an ongoing discussion about usefulness of the term ‘life’. See also:
Null hypothesis: the term ‘life’ is not needed in biology – by Spacek
Cleland & Grinspoon response to Benner: Do synthetic microbes provide another example of life?
Why astrobiologists should NOT get rid of the term ‘life’ – by Cleland
Why the term ‘life’ is useless in astrobiology – by Spacek
Why the term ‘life’ is important to research in astrobiology – by Cleland
Cite as: Spacek, J. (2022) “Are Venusians ‘life’?”. Primordial Scoop, e20220603. https://doi.org/10.52400/AIEG4648
Last February, I contacted Pete Klupar from the Breakthrough Foundation requesting funding for development of Agnostic Life Finder to search for (alien) genetic polymers on Mars. Instead, the Breakthrough Foundation proposed giving me money to research Venus. I was free for the summer (NASA’s proposal would not be decided before Autumn 2021) and therefore I agreed to work on the project: “Are any organics fluorescent in concentrated sulfuric acid?” This is how I got involved with the Venus Cloud Life group.
In February 2021, I knew nothing about Venus or chemistry in concentrated sulfuric acid. Few months later, I submitted a paper proposing an Organic carbon cycle that must be happening in the Atmosphere of Venus. Now, a year later, we have refined the ideas and are ready to publish this discovery in a high-end journal: With Steven Benner, Spencer Cady, and Gage Owens, we discovered completely new organic chemistry in concentrated sulfuric acid. Paul Rimmer provided us with a model showing that formaldehyde is photochemically produced in relatively high quantities to make my organic carbon cycle relevant. Janusz Petkowski made sure that we are not missing some important known facts about Venus. Now we are nearly certain that the UV-vis absorbent and fluorescent complex organics called red oil arising in sulfuric acid from formaldehyde will be present in the clouds of Venus.
The best part is that in the summer 2023, the Venus Cloud Life group will send a Rocket Lab Electron rocket with a small autofluorescence nephelometer probe to study Venusian cloud aerosols. During this first privately funded interplanetary mission, among other things, my hypothesis will be tested, almost a decade before NASA sends their DAVINCI+ and VERITAS missions to Venus.
Our model of the organic carbon cycle in the clouds of Venus has some interesting features. (1) We discovered that in concentrated sulfuric acid, it is easier to produce complex organic compounds (red oil) than in water, when starting from single carbon species (formaldehyde and carbon monoxide). (2) From literature, we know that the red oil formation is autocatalytic. Not in a sense of self-replication, just that the more of the red oil in the solution, the faster red oil is generated. (3) There is an inherent selection: the more of the UV-visible absorbing red oil is in the droplets, the more sunlight they absorb and the more they heat up the atmospheric regions they are in. Heated regions are known to rise to the top of the cloud, prolonging survival of the darker droplets. These phenomena: increase in chemical complexity, autocatalysis, and selection must be happening in the clouds of Venus.
I proposed that there will be selection for ever more efficient chemistry capable to convert carbon gases into the dark red oil. The darker the droplets, the more updraft they will generate, the longer they will stay in the cloud, outcompeting less successful chemistries. If the red oil is complex enough, efficiently self-replicating molecules might arise that would outcompete the less efficient, not self-replicating ones. Evolution, selection, competition.
As far as I know, this hypothesis does not break any physical laws, but it might take couple decades to test it. Even if we get the sample back to Earth, we do not have tools to determine if the chemistry in the droplet was only self-replicating, or actually evolving. So far evolving replicators in the Venusian clouds are sci-fi. But we can still use this sci-fi scenario to discuss very specific aliens (model) and how useful is to call them ‘life’.
At the start of the project, I laughed at the idea that there could be ‘life’ in the clouds of Venus. If you play with heated concentrated sulfuric acid, you soon notice that no organic molecules are stable in it. At best you can get some metastable molecules turning to red oil a little slower than other. Even polypropylene and paraffin turn to dark colored mixtures in a matter of days. No biomolecules we know of (nucleic acid, proteins, sugars, lipid, vaxes) can survive for even seconds in the Venus cloud conditions.
Working on the Venus project, I was certainly not looking for ‘life’, because I thought that ‘life’ could not survive in heated concentrated sulfuric acid. Yet I identified plausible conditions which might support existence of self-replicating and evolving forms of red oil.
Which leads to questions to Carol, addressing specific issues to help me understand her point about usefulness of ‘life’ as a concept in astrobiology:
If we confirm existence of this phenomena (self-replication and selection for darker regions in the clouds of Venus), would that be ‘life’?
Notice that we first must detect a phenomenon, study it, and only then employ philosophers to debate whether it is life or not. Astrobiologists looking for unknown ‘life’ cannot be “looking for life”. Life detecting machines are Sci-fi. Astrobiologists first find something interesting and unusual and then ask their favorite philosopher if the phenomenon they found is ‘life’ or not.
How would you justify calling this specific phenomenon ‘life’ or not?
Since there are no known objective criteria how to determine ‘lifeness’, a decision to call this thing ‘life’ must be a pretty arbitrary decision mostly based on personal feelings and cultural background.
Let us say that in the 2030s we confirm existence of chemical replicators in the Venusian clouds of the proposed type, and in the 2040s we decide whether these are ‘life’ or not. For those who claim that the term ‘life’ is useful, what would be gained by deciding one way or the other?
In my opinion, nothing at all. If we establish their existence in the 2030s, by the 2040s, the term ‘evolving red oil’ will be established; calling it ‘life’ would at best be useless, at worst confusing. Just like with viruses:
Are viruses ‘life’?
We have known about viruses since the 189os. Yet we still have not decided about their ‘life’ status. The fact that we just did not bother to decide one way or the other in over a century, points to the fact that the term ‘life’ had no particular value in modern virology.
Aside from playing with concentrated sulfuric acid, I spend my last summer optimizing Covid-19 tests. From personal experience I can tell you that ‘life’ is useless term in the search for Covid-19.
Why should be ‘life’ useful in astrobiology, when it is pretty useless in virology?
In her most recent last post, Carol concluded “In short, the term ‘life’ is far from useless in astrobiology.” Yet Carol did not provide a single specific example how calling something life or not would help us with gathering knowledge about the thing.
There is no practical use for the term ‘life’ when studying or searching for viruses here on Earth. I doubt that virologist believing that viruses are ‘life’ have any advantage or disadvantage over virologist who believe otherwise, or simply do not care. The same must be true for astrobiology.
The burden of proof must be borne by those insisting the term ‘life’ would have any practical use when searching for potentially more alien phenomena than viruses among the stars.
As I said in the previous posts, ‘life’ is useful to hype the emotions when you are writing grant application or headlines for low brow newspapers. But this is not what I mean by “practical use.”
Simply put, I do not believe that the term ‘life’ provides any more value or meaning than for example a term ‘cool stuff’.
I use the term “life” all the time, this is to put the topics that we study in the context that is broadly understandable, or that can be grasped by everybody, the media, the public, organic-chemistry-averse-terracentric astrobiologists or other members of the scientific community. From that point of view the term “life” is useful. After all we are surrounded by “life” and people appear to instinctively know what is alive and what is not. At least on our scale… I still think that viruses and even viroids (infectious pathogens that are just naked small single-stranded, circular RNAs) are “life”, but this is probably just my personal preference of classification.
However, I do not think that the term “life” is that useful in the search for “life” itself. We do not have to define “life” to search for it.
…so even if the titles of my lectures, and papers etc. contain the word “life” in them, what I really mean is that we search for some chemical phenomena that do not fit the current view of a given planetary environment, we search for chemical complexity and for something that does not fit… In other words, we search for chemical anomalies. There are after all have so many different planetary environments in the Solar System alone that it is unlikely that we will find an environment that will sprout a biochemical copy of our own type of “self-regulated organic chemistry complexity” (we can call it “life” if we wish, but we do not have to call it anything in particular to study it).
What might be useful however, is to try to find some way to generalize such complex organic chemistry phenomena, in a way that does not rely on the existence of specific chemistry. In that regard for example, the presence of the Darwinian evolution and selection is a unifying factor, or Steven Benner’s repeating charge in a genetic polymer, or self-consistency of complex organic chemistry etc. Some characteristics like that might be more unifying than others.
The ultimate question is: where does organic chemistry end and biochemistry begins? I do not know, and in fact, I think that there is no real and clear distinction between the two…
You said “people appear to instinctively know what is alive and what is not” saying that this is a useful feature of life.
I’d say that people’s instincts are exactly the reason why astrobiologists should not use the term ‘life’.
Even you are freely mixing ‘alive’ with ‘life’:
Last person in a spaceship in a galaxy far far away might be ‘alive’, but because she doesn’t have a partner to reproduce with, she is by many definitions (including NASA’s official definition) not ‘life’ because: As a last kind of her species, she is still self-sustaining chemical system, but she is no longer capable of Darwinian evolution, therefore not ‘life’.
‘Life’ from astrobiological perspective is very contraintuitive and I do not believe that astrobiologists can aspire to teach all humans (including majority of astrobiologists) that ‘life’ is a homonym with hundreds of different, often contradictory, meanings. For example viruses are life by some definitions and not life by other. Easier would be to get rid of ‘life’ or ignore it for astrobiology – just life virologists do.
Not just do “not define it”, let us completely ignore the word. Delete the word ‘life’ from your future proposals and papers. Instead say what you are specifically looking for. You never look for ‘life’. You look for specific detectable phenomena: not life but DNA, motility, metabolites,…
Regarding unifying factors, let me ask you this: if we decide to select a unifying factor that is “repeating charge in genetic polymer” and then find ecosystem based on systems evolving using different information storage, do you decide to change the of “unifying factor” or call this system not life? (Are you basing this decision on logic or “intuition” trained on a single example of evolving replicators?)
If you force all life to unite under NASA’s current definition and then discover that a system is not evolving through Darwinian evolution, do you call this “not life” or do you change your definition?
Fun fact: Humanity will very soon no longer be evolving through Darwinian evolution (all it takes is to make mutations non-random and/or selection not natural), hence we will soon not be life by NASA’s definition. I believe that most of the advanced civilizations ‘alive’ in are not ‘life’ by NASA’s definition.
I do not think there is any significant disagreement between us. I just wanted to point out that the term “life” is useful in science communication with a layperson and as a handy thought shortcut.
See e.g. the name of our initiative – Venus Life Finder (VLF) – the name automatically broadly communicates what we aim to do. We aim to look for something amazing, something complex, beautiful and mysterious, but if we would like to have a name that indeed reflects the scientific reality of the VLF initiative (and not be overly long) we probably should call it Venus Complex Organic Chemistry Finder … VCOCF. You often use a term “red oil” in your articles. Recall that the term “red oil” is not exactly a scientifically correct representation of the chemistry that you study. It is not an oil and it is not always red etc. Yet it is a useful umbrella term to describe a certain complex chemical phenomenon in the Venusian cloud environment and in concentrated sulfuric acid. It is a useful thought shortcut, just like the term “life” is.
I agree that “life” is not that useful in purely scientific terms. The more we study the cosmos the more we realize how chemically diverse the environment could be, the more we realize that the unifying factors for the complex chemical phenomena in various conditions might be fewer and fewer, i.e. “life” might be nowhere similar enough to be unified under the single defined umbrella of physical characteristics. It might very well be that the only unifying factor of all complex chemical phenomena in the cosmos (i.e. “life”) is just that, complex organic chemistry. The question is, do we really need such unifying chemical characteristics defined in the search for “life”? As you say, we always look for something specific, polymeric structures, membrane-like structures, metabolites etc. We do not have a “Universal Life Detector” and we likely will never have one, but we might have a “Universal Repeating Charge Genetic Polymer Detector”, and for that reason trying to find such unifying chemical characteristics might be useful.