On a strange and inhospitable waterworld circling Tau Ceti, a spaceship crash-lands, wrecked beyond repair. Its crew, doomed to die within a month from their rapidly dwindling stores and the planet’s poisonous atmosphere, work feverishly to leave a legacy and in some sense complete their mission.
They re-engineer their cells into microscopic humans who can live in the puddles of the planet’s rare islands, safe from the ferocious denizens of the deeps, and die in the hopes they have founded a new race of people.
Thus begins one of the classic science fiction stories of the 1950s, “Surface Tension” by James Blish. It’s one of the most memorable settings for an SF story (we’ll pass lightly over characters and subsequent plot). Since it was written, the idea has entered the zeitgeist and, according to my uncertain memory, appeared in places as far removed as a Li’l Abner cartoon of the ’60s and Disney’s Honey, I Shrunk the Kids.
Blish’s people were 250 microns tall, but for simplicity of calculation, let’s talk about humans 1.7 millimeters tall, 1000 times shorter than the average wild-type human. Such people would have just one billionth the mass and volume of humans: nanopeople.
Is such a nanoperson possible? As far as the body goes, almost certainly yes. There are insects and other forms of life in that size range, so the possibility of an articulated, powered body with limbs is well established, even without resorting to diamondoid bones and Drexler-style electrostatic motors. With them, we can make a body of that size with such a large margin for error that we have wide latitude in varying the existing evolutionary designs (e.g. mites) to match human forms and capabilities.
The brain is a somewhat greater concern. In a biological implementation, the human brain doesn’t have anywhere near the margin to shrink that our bodies do. We have to resort to a more efficient substrate, so that the nanoperson is in some sense an upload to a dedicated processor in a dedicated body. “Nanosystems” gives us a fairly sturdy lower bound of a gigaops (a billion calculations per second) per cubic micron for nanoprocessors, so that in the roughly one nanoliter of brain volume of the human proportioned nanoperson, there’d be room for a petaops (a quadrillion calculations per second), comfortably high in the range of estimates of computation required for human-level thought.
So we have the brain and the body. The thing is physically possible. The question remains: how close can the nanoperson come to having the authentic human experience? Suppose I decided to have myself reincarnated as a nanoperson? Would the world be comprehensible or too weird to cope with? Could I expect to live a happy, fulfilling life, assuming enough of my friends and relatives came with me?
Of course, I don’t mean to ask whether life at that scale (let’s call it the milliscale) would be just like life at the macroscale, but whether it would be close enough to be comparable to other adjustments humans have made over the millennia — from the sun-scorched plains of Africa to the glaciered fjords of Scandinavia; from the close, homey familiarity of tiny English villages to the vast concrete wastelands of LA.
First, the senses. Touch, taste and smell would be little affected. You’d hear in a different range of sound, but it would be mostly appropriate to the phenomena of the environment. Vision would be getting close to the edge of the diffraction limit — really small (to you) things might look fuzzy not because you needed bifocals, but because of optical laws. But that’s a limitation well within the typical range of the human condition. Probably the oddest change would be that people would probably need proportionately larger eyes to help with the acuity. A large part of the human experience is looking at people’s faces.
One of the differences that might not be adequately appreciated today would be the effect of scaling laws (ponder the title of “Surface Tension”). Most physical laws scale so that the pace of motion, reaction time, typical frequencies, etc. at the milliscale would be 1,000 times faster than at the macroscale. On the other hand, if that were completely true, ants would run as fast as you do, and mosquitoes would fly as fast as falcons. There are factors mitigating the fullfledged scaling speedup, including the apparent increase of viscosity and disappearance of gravity with scale. So a nanoperson might get away with only a 100-times speedup of timesense compared to a macro-person. This pushes our estimate of available processing power closer to the edge but still seems well within the range of reasonable possibility.
To a nanoperson then, a millimeter would be like a meter and a centisecond like a second. If our nanoperson held an object and let it fall the length of his foot, it would take nearly a centisecond to fall the distance. And that would be in a vacuum — any object of a given density would have a thousand times the air resistance per weight as at macroscale. So you’d essentially live in a world where gravity was a long-term tendency, and things pretty much stayed wherever you let go of them.
This would be magnified by two more phenomena. First, there’s surface adhesion. We don’t notice this too much at the macroscale, but any animal smaller than a gecko uses it to great effect. In the natural world, everything is covered with sticky glue, which we call moisture.
a nanoperson might get away with only a 100-times speedup of timesense compared to a macro-person.
Secondly, inertia wouldn’t count for very much. On the other hand, remember the quip that to a close approximation, every animal can fly: to a close approximation, every animal is an insect, and to a close approximation, every insect can fly. Given very tiny wings to wave by hand, our nanopeople — noticeably smaller than mosquitoes — would have no trouble flying. We may as well build them in.
The overall effect might be something like the world experienced by a scuba diver.
The bottom line is that things would be different, but not that much more different than many of the lifestyle changes people have made in our history. You’d have a whole new world to conquer, filled with fearsome beasts (insects) and grand adventure. We’d have picked up a factor of a billion slack in usable resources on the Earth (maybe only 10 million given the faster metabolisms). You could comfortably house the entire (current) human race in a building the size of a typical suburban house — or give each person a 5 million acre estate.
J. Storrs («Josh») Hall, PhD., is president of the Foresight Institute, founding Chief Scientist of Nanorex, and author of Beyond AI and Nanofuture.