I wonder what possible harmful life they could have detected.
Suppose for the sake of argument, a different form of life had developed or were somehow present as spores on the Moon, and it was from an entirely different environment.
This means different amino acids, a different codon scheme, maybe even more radical changes that that. This ‘alternate life’ would be completely incompatible with earth life.
Assuming it didn’t simply die immediately, one of the few ways it could plausibly work would be some type of photosynthetic bacteria or multicellular plant that can exist solely on digested materials found in earth’s biosphere. It can’t depend on any existing protein.
An actual deadly organism would be some kind of photosynthetic plant that is superior in performance to anything evolved on earth. It would fill the earth with copies of itself, a “green goo” plague that slowly outcompetes everything else.
And it wouldn’t necessarily be obviously harmful. A toxin is often a molecular weapon aimed at a specific target for earth life. For example botulism toxin targets a specific form of nerve signaling using acetylcholine, and only specific variants of the toxin will even affect mammals. Any slight variation from a different evolutionary lineage, and it won’t work, at least at the doses where this toxin is dangerous to humans.
Probably your first sign this has happened would be a slowly spreading patch in the ocean of whatever color photosynthetic pigment (probably black) that a superior organism uses.
Yeah, great point! So to be fair to them, they were not doing tests that hinged on it having a specific codon scheme or amino acid. Like, they weren’t sequencing the samples—it was 1969, they couldn’t do that. They were putting it in nutrient-rich media or plants or animals or etc and seeing what happened. So maybe in such a case the coloration change would have been detected in, I don’t know, the water of the shrimp tank. But as you say it could well have been too late at that point, if an organism grew in seawater.
Yeah. I was thinking that none of the shrimps would die because the ‘green goo’ bioweapon isn’t harming anything. It’s just doing better than anything that could evolve naturally.
Evolution is a hill climbing algorithm that is only able to search places nearby in the possibility space to existing living organisms. Mostly it can only even ‘check’ 1 codon mutation at a time places, though with redundant genes it is possible to explore a bit deeper than that.
Evolution also has the limitation that it can’t make any major changes to the way a cell works if the changes will reduce fitness significantly. So it’s stuck at a local minima, and the codon encoding limits restrict all life on earth to within a limited region of the possibility space.
An organism from another planet could be better or worse, I’m not sure what the odds are. I want to say 50% but anthropic principle may mean that life on earth ‘rolled high’ for fitness in order to eventually discover mammals.
Also another way to think of green goo is it might only be 1-10% more efficient than earth life. It’s more efficient because maybe it has access to amino acids that allow for better ribosomes or chloroplasts or just a cell wall that earth enzymes cannot digest. It can’t be that much more efficient, it’s still operating in the same environment collecting energy slowly via photosynthesis, there is only so much energy and materials dissolved in seawater available.
This is why it would take so long to consume the planet, and it is possible to stop it. Synthetic herbicides could exploit the fact that the alien plant uses different biochemistry, so humans could just try candidate molecules until they find one that works. That would have been possible in 1969.
Also because the tiny plant is only a little bit more efficient, it would need a day or so of time to double under a light source—you wouldn’t see anything without waiting for weeks.
Reminds me of the risk from mirror organisms. Basically you create cyanobacteria using right handed amino acids instead of left handed ones, and it outcompetes everything else because nothing can predate it (it’s indigestible to normal organisms).
Right. It’s the same idea. The one I gave above is essentially that https://academic.oup.com/nar/article/34/1/e7/2401668 there are other amino acids nature didn’t have a choice between. Probably a photosynthetic bacteria that was ‘designed’, by accident or evolution, from a larger set of amino acids or on a different world would have an efficiency or defense advantage. So slowly over time with each generation, a small advantage means slightly more of the algae in an ever expanding bloom is this alien life.
I think the reason this doesn’t normally happen is within the possibility space of earth life, there are rarely truly dominant advantages, so eventually this bloom would hit a limit of the biomes it’s optimized for, or other creatures would evolve to eat it, or it would have it’s advantages copied by gene transfers.
But in theory an alien organism could have an efficiency advantage in all conditions that earth has, and obviously it can’t be eaten and it’s genes are not intercompatible with earth life.
I wonder what possible harmful life they could have detected.
Suppose for the sake of argument, a different form of life had developed or were somehow present as spores on the Moon, and it was from an entirely different environment.
This means different amino acids, a different codon scheme, maybe even more radical changes that that. This ‘alternate life’ would be completely incompatible with earth life.
Assuming it didn’t simply die immediately, one of the few ways it could plausibly work would be some type of photosynthetic bacteria or multicellular plant that can exist solely on digested materials found in earth’s biosphere. It can’t depend on any existing protein.
An actual deadly organism would be some kind of photosynthetic plant that is superior in performance to anything evolved on earth. It would fill the earth with copies of itself, a “green goo” plague that slowly outcompetes everything else.
And it wouldn’t necessarily be obviously harmful. A toxin is often a molecular weapon aimed at a specific target for earth life. For example botulism toxin targets a specific form of nerve signaling using acetylcholine, and only specific variants of the toxin will even affect mammals. Any slight variation from a different evolutionary lineage, and it won’t work, at least at the doses where this toxin is dangerous to humans.
Probably your first sign this has happened would be a slowly spreading patch in the ocean of whatever color photosynthetic pigment (probably black) that a superior organism uses.
Yeah, great point! So to be fair to them, they were not doing tests that hinged on it having a specific codon scheme or amino acid. Like, they weren’t sequencing the samples—it was 1969, they couldn’t do that. They were putting it in nutrient-rich media or plants or animals or etc and seeing what happened. So maybe in such a case the coloration change would have been detected in, I don’t know, the water of the shrimp tank. But as you say it could well have been too late at that point, if an organism grew in seawater.
Yeah. I was thinking that none of the shrimps would die because the ‘green goo’ bioweapon isn’t harming anything. It’s just doing better than anything that could evolve naturally.
Evolution is a hill climbing algorithm that is only able to search places nearby in the possibility space to existing living organisms. Mostly it can only even ‘check’ 1 codon mutation at a time places, though with redundant genes it is possible to explore a bit deeper than that.
Evolution also has the limitation that it can’t make any major changes to the way a cell works if the changes will reduce fitness significantly. So it’s stuck at a local minima, and the codon encoding limits restrict all life on earth to within a limited region of the possibility space.
An organism from another planet could be better or worse, I’m not sure what the odds are. I want to say 50% but anthropic principle may mean that life on earth ‘rolled high’ for fitness in order to eventually discover mammals.
Also another way to think of green goo is it might only be 1-10% more efficient than earth life. It’s more efficient because maybe it has access to amino acids that allow for better ribosomes or chloroplasts or just a cell wall that earth enzymes cannot digest. It can’t be that much more efficient, it’s still operating in the same environment collecting energy slowly via photosynthesis, there is only so much energy and materials dissolved in seawater available.
This is why it would take so long to consume the planet, and it is possible to stop it. Synthetic herbicides could exploit the fact that the alien plant uses different biochemistry, so humans could just try candidate molecules until they find one that works. That would have been possible in 1969.
Also because the tiny plant is only a little bit more efficient, it would need a day or so of time to double under a light source—you wouldn’t see anything without waiting for weeks.
Reminds me of the risk from mirror organisms. Basically you create cyanobacteria using right handed amino acids instead of left handed ones, and it outcompetes everything else because nothing can predate it (it’s indigestible to normal organisms).
Right. It’s the same idea. The one I gave above is essentially that https://academic.oup.com/nar/article/34/1/e7/2401668 there are other amino acids nature didn’t have a choice between. Probably a photosynthetic bacteria that was ‘designed’, by accident or evolution, from a larger set of amino acids or on a different world would have an efficiency or defense advantage. So slowly over time with each generation, a small advantage means slightly more of the algae in an ever expanding bloom is this alien life.
I think the reason this doesn’t normally happen is within the possibility space of earth life, there are rarely truly dominant advantages, so eventually this bloom would hit a limit of the biomes it’s optimized for, or other creatures would evolve to eat it, or it would have it’s advantages copied by gene transfers.
But in theory an alien organism could have an efficiency advantage in all conditions that earth has, and obviously it can’t be eaten and it’s genes are not intercompatible with earth life.