We Are the Nanites

As an academic biogeochemist, I’ve done a lot of research into weird ways that bacteria can make a living on Earth, chemically speaking. I also have a strong love of science fiction, for its ability to speculate about how weird the laws of physics can allow things to get without invoking cheats, like warp drive or “psionic” powers. A natural combination of these two interests led me to one of my weirder hobbies; thinking about alternate biologies that might be possible, or which could have evolved on Earth but just didn’t happen to in the course of the last 4 billion years on this planet.

I’ve also been involved in research into the origins of life on Earth, explored through the lens of geochemistry. “Emergence of life” research is an active and vigorous field today, and it requires one to think about life in very interesting and fun ways. We carry in our blood a profile of salts and trace elements that is a fairly good match with seawater. That’s not a coincidence. All life on Earth evolved from precursors in the global ocean, where they emerged as amalgams of elements found in seawater or rocks on the seafloor. Life is a product of geochemistry.

Thinking in these terms opens up a whole new spectrum of possibilities, because when you think of life as a kind of nanomachine invasion, it’s easier to imagine life as the desperate, ad hoc, relentless process that it really is. Bacteria are tiny machines made of protein and fatty acid chemo-mechanical components. They are designed, and the designer is natural selection.

Bacteria can proliferate at incredible rates, constantly making duplication mistakes and generating millions of random mutant copies. A single bacterium can double itself every 20 minutes, if it can get enough fuel. In fact all a bacterium really does is try to duplicate itself. A bacterium is a replication machine, with individual molecules as moving parts.

At the level of a bacterium, mutating a single amino acid in a single gene could flip a bacterial protein factory (called a ribosome) from cranking out a normal protein molecule to making a bent, cracked, shoddy version. But shoddy to one job may be great for another. Mostly when you flip a random switch in a protein factory you’ll end up with crap; a poor substitute for the original at best. But sometimes you can hit the TV just so and channel 47 suddenly comes in clear as a bell. Sometimes after a ribosome tosses out a crappy protein molecule, that crappy product works pretty well doing something else. Maybe it gets snatched up onto a different conveyer belt, to a different cell function, where it does a fabulous job at some obscure menial position. The new crappy protein gets a promotion, and the shoddy ribosome just keeps making it.

Consider that one bacterium with enough fuel can replicate itself into a trillion more in an afternoon. Also consider that a lot of those trillion will end up being mutants with new, untested modifications. Hopefully you begin to see where a trillion afternoons might take that one bacterium.

Failed modifications are thrown aside, cannibalized for parts and fuel, by better-operating protein-microbots, who out-replicate their more handicapped brethren. Impractical modifications are weeded out. Mutations that do something, anything, that keeps the replication engine tugging along are able to pay their own way and define the survivors of each generation. A billion are built, but only ten drive away… so you better believe those are the bloody best ten the factory made that day. Each drives off to set up its own factory, making copies of itself. And so on.

Serendipitous mistakes become part of the new design specs. Lucky mistake on top of lucky mistake, and over the years the landscape of successful robot models changes drastically. In time, the robot environment includes highly-outfitted microbots cruising around on sleek, trendy propulsion systems, bristling with bizarre molecule guns and protein-filament grappling cables, hulls studded with chemical sniffers and portals disgorging molecular traps to disable competitor bots. Some models use coded signals and mechanical supports to erect massive structures, built of myriads of individuals, if fuel resources are sufficient. These immense collectives move like titans among the singleton swarms, siphoning up resources and fuel. Eventually the world becomes a confusing, teeming robotscape of complex, rumbling titans striding among a sea of tiny, persistent invaders, the best their accumulated history of filtered mistakes can afford them.

That is basically what life on Earth is like, and has been for over 4 billion years. We don’t have to worry about people building nanites that take over the world, because that’s already happened. The world is owned by nanites made of the most common elements found on Earth’s surface: carbon, oxygen, nitrogen and hydrogen, along with whatever minor elements can be scraped or gouged or dissolved from rocks. Those biomachines have had a long time to stack up happy accidents, and the result is our biosphere.

In Michael Crichton’s abysmal novel Prey, rogue nanomachines are released by accident, and soon multiply and evolve into a thinking swarm of malevolence that can take human form. People seem to have little trouble swallowing that in their fiction, so why so much resistance when the machines are made out of seawater and protein instead of silicon and plastic? Evolution is more amazing than we give ourselves credit for imagining. The beauty of evolution by natural selection is its blind, frantic creativity, using only what is available to fashion new things, multiplied by a trillion generations. One gets a deep source of awe from the realization that Darwinian selection can theoretically happen in any system where information can be encoded and objects can self-replicate. We have one example on Earth of this scenario arising from carbon chemistry in the presence of an aqueous solvent (water) and rocks, plus energy (the Sun, volcanic gases, geothermal heat). What other systems of components can exhibit this epiphenomenon?

I fail to see how anyone can think about evolution and not be amazed at the inherent complexity in our Universe, at what grandiose possibilities are allowed by natural processes. What is more amazing, a trilobite fossil, or a sculpture of one? The created fossil is interesting, but shallow and feeble when compared to the alien reality of a living breathing trilobite inhabiting turquoise tropical waters, scuttling in sand to evade monstrous predators with five eyes, buried in an undersea mudslide, preserved in effigy for 500 million years while mountains buckled and sea beds opened, and now resting in heroic repose on a museum shelf, ready to awaken the curiosity of a distant, far-future cousin; a ten-year old human on a school outing.

Who can look at such an epic natural phenomenon as evolution and not be totally blown away? By comparison, a surly desert god who can whip up a universe in a week, but who takes sides in human tribal disputes and is obsessed with my sex life, seems really pathetic.

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~ by Planetologist on September 12, 2008.

5 Responses to “We Are the Nanites”

  1. If you didn’t like Crichton’s book then you missed the point. It was about technology gone awry. The beginning sums it up pretty well. People embark on an endeavor, thinking they have all the bases covered (when no one can ossily cover ALL of them) and proceed downunwise paths because something unexpected happened. In the future, others will follow, thinking THEY have all the bses covered and the previous group didn’t know what they were doing in the first place. ‘Pride goeth before a fall.’

    Other than that, it starts out as pretty much any other movie on the Sci Fi channel.

  2. […] to slowly catch up with what natural evolutionary processes have already invented. As I’ve said here before, viruses and bacteria are naturally-occurring nanomachines, self-constructed from common materials […]

  3. Thanks to you both for coming to take a look!

  4. Wow! Fantastic blog. I’m adding you to my reader. Keep up the good work.

    I never fail to be awed when I think of the origins of life and where unguided natural selection has taken us. It will be fascinating to watch what, if anything, comes of our contamination of Mars.

  5. Thank you so much for starting your blog!

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