How Alien Might Real Aliens Be?
They probably don't really look like this
Do movies get it right?
Encounters with alien life are a staple of science fiction. Movies and TV are full of humans and aliens talking, fighting or relating in even more intimate ways. But how realistic is it? Laying aside the substantial question of whether or not we are alone in the universe. What kind of aliens might be out there if we aren't? In live action film, presentation of an alien requires something that can respond to direction. The performer also had to do this despite the distraction of whatever accoutrements were required to make it look otherworldly. Usually this required either a human in heavy makeup (or a rubber suit) or a Muppet. Prior to the release of the Empire Strikes Back even a Muppet was considered a risk. Today, of course, computer graphics have reached the point where any creature that can be conceived can interact with human actors. Provided the special effects budget is big enough. How realistic are even the most alien of these fictional aliens?
The science of biological form
We do know some laws governing how they might look
The study of how living organisms are shaped is called morphology. Scientists who study the subject have discovered some rules that should apply even to extraterrestrial life. For example creatures that move about in a fluid with a density and buoyancy similar to that of water will evolve similar streamlining. A dolphin and a shark got there by different routes but have evolved nearly identical solutions to their environment. Dolphins and sharks are also an example of another rule. Although their pectoral fins look nearly identical on the outside the internal structures are completely different. This is because evolution has an easier time adapting existing structures to a new purpose than creating a whole new structure. This is why birds wings are so different from those of bats, despite having the same function. The two limbs started from different evolutionary points and nature adapted what it had. Naturally alien environments will create different problems but the physical laws evolution will have to work within are the same throughout the universe. Even aliens with radically different biochemistry should evolve similar physical forms to cope with similar conditions. The more different an aliens environment the stranger its form may be to adapt.
The gravity of the situation
- The Habitable Exoplanets Catalog - Planetary Habitability Laboratory @ UPR Arecibo
The Planetary Habitability Laboratory (PHL) is a virtual laboratory dedicated to the study of planetary habitability. The PHL is managed by the University of Puerto Rico at Arecibo (UPR Arecibo)
- The Pull of Hypergravity - NASA Science
By spinning people in a giant centrifuge for 22 hours at a time, a NASA researcher is learning more about the strange effects of artificial gravity on humans.
We have only recently begun to discover potentially earth-like planets orbiting other stars. As the techniques and tools used are refined we've gone from a handful to hundreds of potential candidates. Several of the best candidates so far are much larger than earth however with higher gravity. While several candidate worlds are much closer to earth in size this does raise an important point storytellers often overlook. How easy will it be to interact with an alien native to even twenty percent different gravity? People from Earth on a lower gravity world will face muscle atrophy. On a higher gravity world the same people would face at minimum joint strain and cardiovascular issues. We haven't yet found signs of worlds with gravity so high that their inhabitants could, “Leap tall buildings with a single bound.” Here on earth. That doesn't mean such worlds and aliens don't exist. Such a being will have difficulty passing for human though. If it's biochemistry is similar enough to survive on terrestrial food then it's physiology would have much thicker limbs adapted to holding it's weight up on it's home world. If, however, our super alien had more human proportion limbs that would imply it's bones and muscles were made of much stronger materials, which would require a much different diet to nourish. Even if it had a biology that used materials like fulurines it would need nutrient catalysts quite different from what humans think of as vitamins.
Building blocks of alien life
- Life's Building Blocks 'Abundant in Space' | Space.com
The idea that comets and meteorites seeded an early Earth with the tools to make life has gained momentum from recent observations of some of these building blocks floating throughout the cosmos.
- Panspermia - Wikipedia, the free encyclopedia
- Extremophile - Wikipedia, the free encyclopedia
Proteins come from building blocks found throughout the universe
How to make an alien
Considering different biochemistry raises other differences that might exist between humans and any aliens we might meet. Many of the building blocks of earth life have been discovered in space These building blocks are so prevalent it has let to the theory that life may actually exist in space, at least in bacterial form. If the theory of panspermia is true then life that is somewhat biochemically similar to us will not only be common but ubiquitous. Just because aliens have the same biochemistry does not mean their will be any other similarities. For one thing the amino acid building blocks of life on earth are all “left handed” (a term chemist use to differentiate virtually identical organic molecules) but life elsewhere might use right handed molecules. This could be a severe problem for anyone planning on colonizing an alien world as proteins with the wrong orientation will be indigestible. Imported plants might even have trouble growing in soil with the wrong molecules as well. Even if an alien's proteins are oriented the same as ours that may be the end of the similarities. Life on earth existed for millions of years before photosynthesis released Oxygen into the air. It took even longer for life to adapt to use it. We have every reason to assume different conditions will lead evolution in different directions. Here on earth creatures around deep sea volcanic vents have metabolisms that revolve around Sulfur. On other worlds they might breathe Chlorine, Florine or if the environment is exotic enough life might evolve to breathe chemicals that aren't even gasses here on Earth. Life here on Earth has evolved to fill environments that are deadly to humans. There is every reason to suspect that alien life will thrive in environments even more hostile.
Is it a machine or the home of an uploaded mind?
Life on stars?
It could be stranger still
Even stranger is the possibility that elsewhere in the universe life may have evolved based on Silicon or other elements. Some authors have even gone so far as to suggest life that exists as stable plasmas paterns on stars. Then there is the question of what life like us might evolve into. Advocates of transhumanist philosophy suggest we should actively take control of our evolution. The extreme version of this idea suggests that humanity forgo our organic forms entirely in favor of uploading our minds as software. If we run into an alien race that has taken this route will we even recognize them as life? Such electronic minds would have a huge advantage in exploring the universe. With proper hardware maintenance and backup copies they would be virtually immortal. They could bridge the vast distances between the stars offline and not even worry about getting bored. If digital minds reproduce by means other than direct copying (mixing code for personality elements perhaps) their may be beings out there who don't even remember that their ancestors were organic.
They won't look like us
Even if aliens are still organic, unless they evolved under virtually identical conditions to our own world they're not likely to look all that familiar. Even aliens from a virtual twin of our world may not be comfortable under the same conditions we are. Our atmosphere had a higher concentration of Oxygen during the time of the dinosaurs. An alien accustomed to those conditions would gasp for breath in conditions humans would find normal. Mention of dinosaurs also raises another point. The existence of the human species is an eye-blink in terms of the history of the Earth. The existence of our planet itself is an eye-blink in terms of the history of the universe. Meeting aliens who are not only intelligent but at the same technological level as us is mind bogglingly unlikely. We may run into hunter gatherers or beings whose technology is literally millions of years ahead of ours. Even more likely we may find worlds with life where no intelligence has evolved. After all every other species in the history of our world has gotten by without it. We might also find artifacts left behind by alien races that are no longer around. Aliens that have gone extinct, left their settlements behind or perhaps saw our primitive race coming and benevolently stepped aside to avoid inadvertently hurting us. One thing is certain. Any aliens we find will be quite different from us.