The most unrecognizable shapes life can take in the cosmos
We have always made aliens more like us. They’ve been humanized over the years — given desires, made helpful and resourceful and often terrifying. Most depictions show them imposing on our world and transforming it into a war zone. In one of the most assertive lines from the 1986 Aliens, the protagonist says, her voice grainy but indomitable, “Just tell me one thing, Burke. You’re going out there to destroy them, right? Not to study. Not to bring back, but to wipe them out?” But our struggle with alien life isn’t always so explosive. Oftentimes our wars with these creatures are quiet and internal, happening only in the dead of night through abductions or inside our bodies where they have come to nest. We’ve given them wide, watchful eyes and arms and legs that jut from a familiar torso. Their shape is our shape, mutated.
And in some ways, that view of extraterrestrial life is based on well-known phenomena like convergent evolution. This type of evolution results in creatures that have similar characteristics despite being only remotely related. Cat-like predators stalk the island country of Madagascar where no wild cats have ever roamed. Instead the animals look similar because their environments and diets have given way to retractable claws and sleek bodies covered in matching ember-colored coats. The same solutions arise to solve the same problems, giving us features that come up time and time again.
Our views of aliens are certainly based on the only example of life we know — our own. But extraterrestrial life can take forms so strange and unlike ourselves that we’d be hesitant to call it life at all.
Is it possible some lifeforms may be inorganic? That they’re surrounding us even now?
Because of convergent evolution, an Earth-like planet will have conditions that encourage wings, eyes, and teeth. Some of the most habitable places in the universe are the heady super-Earths. With masses several times that of the Earth, the stronger gravity allows for shallower oceans and a greater rate of island archipelagos. These temperate geological formations — as opposed to the extremes of the deep sea or huge continents — encourage biodiversity and larger populations of organisms.
But the most important convergent trait remains that of intelligence. We shared it with our extinct counterparts, the Neanderthals. We share it now with clever octopuses, crows, elephants and tool-wielding chimpanzees. It would give any organism a survival advantage much like the one it’s given us. This first picture of alien life, then, is a comfortable one: intelligent organisms in either the role of predator or prey, likely to communicate with other members of their species and evolve teeth and appetites for a large variety of foods. Their body parts are responses to their environment — ways to sense heat and sound, perhaps even ways to sense electric or magnetic fields. We can expect to see the usual eyes, joints, brains, and body parts used for defense or for hunting. Though striking physically, we can still relate to this picture of life.
But what about the life we can’t relate to —truly alien aliens, the life that has no mouth and doesn’t eat, has no desires and no agendas? And if its chemistry isn’t carbon based like ours then will we ever call it life at all?
In our Solar System there’s two promising locations for life, both of them moons. Europa exudes vaporous plumes and has a thick, briny ocean sloshing around beneath its ice. On Titan lakes are made of methane and organic compounds swirl in the atmospheric haze. These bodies of methane in particular could be solvents of silicon, among the most abundant elements in the universe and a member of the same chemical group as carbon. Carbon is the chemical upon which we are based and is well suited as a building block to life because it can form long chains of molecules for DNA and proteins. While it’s uncertain if purely silicon life can exist, there can form bonds between silicon and carbon by where strange structures might emerge — silicone fluids acting like blood, skeletal systems made of silicates and covered in silicone membranes. There are even some algae on Earth that use silicon dioxide in their skeleton.
But life can get even more unrecognizable than that.
A paper was released in 2007 by Vadim Tsytovich et al. on the structures known as plasma crystals. Though they are nothing more than dust and plasma, these structures exhibit all the properties of living organisms, including the formation of double-helixes akin to DNA. Plasma is a collection of charged particles that often veins itself through interstellar clouds where they’re able to mix with flecks of dust. After the dust arranges itself into helices, it draws energy from the plasma and can go on to reproduce by dividing itself into two identical copies, just as human DNA is duplicated before cell division. The plasma crystals may morph into more complex structures. They are even capable of encoding information through variation in their width and length.
Yet there was nothing organic about the plasma crystals. Though they could retain information and reproduce in the environment of space, they weren’t based on carbon or water. They engaged helices and spirals like our cells and these could evolve and even interact with each other to produce changes. Unlike normal crystals, these helical structures were endowed with bifurcations serving as memory marks — a characteristic which coupled with reproduction can form the basis of a “living material”. A faster evolution rate into more complex arrangements would come from a competition for plasma energy, not dissimilar to how competition for food has driven animal evolution in our own past.
Few people would be willing to call plasma crystals alien life, but it’s a question which will loom over us in our exploration of the cosmos. How unrecognizable can an intelligent lifeform become before we’re unwilling to treat it as living? Tsytovich and his colleagues propose plasma crystals could create a search for alien life not out there, on the foggy shores of a tropical exoplanet, but here on Earth where laboratories could investigate inorganic life. Inorganic life which may, over time, spur the creation of the organic life we’re more familiar with. The one that’s a bit more humanized. Alien life that treads and crawls, that fears and wants.
All Rights Reserved for Ella Alderson