Wondering what aliens may look like has been a question humankind has been imagining for decades. There only seems one thing people can agree on when it comes to conceptualizing aliens: we have no idea what they really look like. But, scientists are working on trying to get closer to a correct conceptualize of lifeforms that may one day visit us.
One movie immediately springs to mind when I think about aliens: ET. In the Steven Spielberg movie we have "an alien botanist and explorer who became unwell after being abandoned during an expedition to a forest in North America." In an interesting scholarly investigation into ET, Gregory Scott and Edward Presswood present their findings and analysis of ET. They describe him as, "ET is a bilaterian tetrapod, sharing many of the physical characteristics of primates. Given that ET’s species evolved on a remote planet, the similarities are a striking example of convergent evolution." According to ScienceDaily, convergent evolution "is the process whereby organisms not closely related (not monophyletic), independently evolve similar traits as a result of having to adapt to similar environments or ecological niches." Although his age is unclear, as his gender (although he seems to be presumed male) we do know he weighs roughly 35 pounds and is about 4ft 6".
But ET isn't the only movie alien that remains front-of-mind for many people - there is Alien, Mars Attacks, Earth Girls are Easy, District 9, Independence Day, War of the Worlds, and Men in Black. In each of these movies aliens are depicted in completely different ways - from little green men to humanoid beings to completely inhuman.
However, researchers believe they may have a better idea now what aliens look like. Why? Well, we can thanks Charles Darwin for that. Samuel Levin, co-author of a new paper published in the International Journal of Astrobiology, believes that beings on other planets might look shockingly similar to life on Earth. Why? Because, like on Earth, living beings on other planets would also be subject to some kind of Natural Selection, even if isn't carbon based or has different DNA or, like ET, light-up fingers.
Levin emphasizes, "Living things are adapted...They appear to be 'trying to do things' like eat, survive, grow, reproduce." And, the only way to adapt is through Natural Selection.
But what does this have to do with what aliens look like?
Although we would be no closer to confirming aliens are or are not little green men or face eaters or even have similar features like eyes or noses, we can take on a theoretical prediction. For example, if the theory of Natural Selection holds true than "Aliens that have undergone natural selection would be "nested." This means that they would have had to transform in complexity over time and that they would retain the history, of sorts, of their transitions. For further proof, the scientists suggest that the only thing we know that can just arise without natural selection are molecules. Furthermore, it means that anything "more complicated than a virus" has certain objectives. Even something as small as a bacteria cell still moves and eats.
Levin continues, "Aliens might not be made of cells as we think of them, but they will be made up of parts that were once free living, and those parts will be too – all the way down to aliens’ hereditary material (whatever it is). Our parts have mechanisms in place that keep all the parts working together to make an organism."
Although aliens might look insanely different, their actual structure on a fundamental level will likely be more similar than their outward appearance suggests. Their bodies, like ours, would have to be constructed by "formerly free-living parts within formerly free-living parts...and they will have undergone a similar evolutionary history' of independent organisms cooperation to form new and even higher level organisms.
Levin notes that his work does not answer the overarching question of "are we alone?" But, he does say: "but it [their research] does tell us something about our neighbors if we're not alone."
The above image is unrelated to the story and was provided by the NASA Goddard Space Flight Center and is liscensed under Attribution 2.0 Generic (CC BY 2.0).