This post is a sequel to this one about alternatives to water-based biochemistry.
Or maybe a side-quel, because actually I am talking about water. Water vapor!
Imagine a cloud of droplets, each with some sugars dissolved in it, each surrounded by a phospholipid shell. Proteins link one droplet to another. It’s an inside-out cell.
According to atopics, droplets in clouds, fog, and mist, range from 1 to 100 microns in diameter, which would comfortably fit anything from bacterial cells (3-5 microns) to mammal cells (50 microns). Raindrops are 1,000 microns in diameter, and living droplets could grow even larger without falling (by, for example shaping themselves into parachutes, or by directing force applied by the wind from one part of the cloud to another, or by chemical propellants, or focusing sunlight to produce heat). So the scales work. I think the challenge will be in the composition of the microtubules that connect one droplet to another. I’ll look up strong, light polymers. 😉
And speaking of which, wasn’t there something recently about spider silk using static charge to generate lift? What about a spinning cloud generating a current? Ionoplanes? Moving along a planet’s magnetic lines?