Just listened to a geeky podcast about what technologically advanced alien life if it exists could look like. The only way anyone can look at this is based on what we know about physics & how life has evolved on Earth.
The first thing to look at is size & this is linked to gravity & atmosphere. Dinosaurs existed at a time when the Earth’s atmosphere was thicker than it is now, it had greater oxygen levels. Many dinosaurs couldn’t exist now as their muscles would not be able to support their bones & the effects of gravity on them, as the Earth has less oxygen now than it did in the prehistoric past. A thick atmosphere helps to provide a buoyancy much like water does & organisms can grow larger as this buoyancy helps support their weight, this is why creatures in water can grow massive.
The kind of planet that can support life is one that isn’t too massive or too small. A planet like Mars is on the edge of being too small. Based on what we know for life to exist on a planet, that planet needs an atmosphere, if the planet’s gravity isn’t strong enough, then it won’t be able to pull in a thick enough atmosphere; but if the planet’s gravity is too strong like Saturn, then the atmosphere will be too thick & create massive devastating storms, like the eye of Jupiter which is a storm the size of 2 – 3 earths & has been going on for hundreds of years, at least since the 17th century where it was first recorded.
Large organisms generally don’t need technology for survival, so they don’t evolve the same problem solving brains. Because it is so big, most of the other organisms will leave it alone. (Except the ones who develop technology or ones that are bigger.) So in theory aliens won’t really be much bigger than us, some might be a bit taller, but most likely they will generally be smaller than us. The smaller & more vulnerable you are, the more likely you are to develop problem solving brains to survive.
If technology needs tools then there must be a means to manipulate the tools. Organisms such as ourselves are vulnerable to predators, & not particularly brilliant at catching prey. However with tools we have overcome our vulnerability & have become the most feared & deadly organism on the planet, with the power now to destroy every living thing on it if we detonated all our nuclear weapons.
So a technologically advanced alien would have some thing it uses as hands. This doesn’t necessarily have to be like our hands though. The aliens could use their noses like elephants use their trunks. Or their tongues like giraffes do, or even their ear lobes to manipulate the tools.
Most likely the alien’s eyes, ears & nose will be located close to the brain, as a sense relays the information faster the closer it is to the brain. Octopus are interesting in that they are conscious, can solve problems, have memory, even get dementia in old age, but their brain is completely alien to ours, their whole body is their brain.
Which raises another interesting thing about evolution there seems to be a point were evolution reaches the same point or limit. The way birds & bats fly is very similar yet they both evolved from a different evolutionary branch.
Marsupials evolved many of the same kinds of animals as mammals did.
Human eyes & an octopus or squids eyes are almost exactly the same. We are two creatures that went down completely alien evolutionary paths, yet we have developed the same eyes.
The aliens eyes would need to be in a fixed elevated position, because that is the best position for them to be. If you had eyes on your hands or feet or lower down in your body, survival would be trickier and so would using tools & building things.
You are unlikely to have lots of eyes because it would use up too much energy. Nature is lazy, it always takes the path of least resistance, this is because energy is what keeps an organism alive & able to move & survive, so being able to conserve as much of it as you can is vital. So technologically advanced aliens will most likely have two eyes, as that is pretty much what every animal on earth has, bar insects who have lots, but the smaller you are the less energy you expand counteracting the effects of gravity & the more you can invest in extra body parts & perks. It is possible technogically advanced aliens might be no bigger than the size of fleas…
But all eyes in nature tend to be located high up, as it gives the best vantage point and makes it easier to build a good perspective of the environment around you, move your limbs, manipulate tools & develop hand eye coordination. Same applies to hearing & smell.
The mouth is likely to be located high up as well, this is so gravity can assist in the digestion of food, nature always tries to take the path of least resistance, as it means expending less energy, & will use the laws of physics to help with things like digestion.
Language is a given, there has to be some way for the aliens to communicate complicated ideas with one another, there would have to be writing too.
Technologically advanced aliens may not be very nice. History shows that humans who lived in harmony with nature as tribal hunter gatherers got invaded & beaten by those humans who had developed superior weapons & larger communities. In order to develop superior weapons you have to have a desire to crush your neighbours so you can claim the land for yourself , which means you have to be pretty ruthless & nasty. So it is likely any other technologically advanced species out there is as nasty & manipulative as we are & probably not someone we want to meet.
Unless of course they evolved past that part of their history & developed compassion, if so they may be less inclined to want to bump into other intelligent creatures who don’t share their feelings of compassion & if they do explore the universe are probably wise enough to stay hidden. So we are more likely to encounter the less compassionate ones, who are probably very aggressive, deceptive & have developed more advanced deadly technology than the compassionate ones. Cause for the compassionate ones to develop high tech weaponry they would have to not be so compassionate.
Having said that, the more aggressive less compassionate ones would have to have a degree of compassion also, as kindness is necessary to form teams & communities, people generally tend to cooperate more & work better together if they’re nice to one another. Without kindness they are likely to blow themselves into oblivion & never reach the stage of interstellar space travel.
All in all it is probably best we don’t try to make contact with other technologically advanced alien life in the universe, cause the odds are the ones who reply will be just as unpleasant & manipulative as we are, perhaps more so.
Unless they are the size of insects, or perhaps even smaller, & like in Douglas Adams ‘Hitchhikers guide to the galaxy’ their whole space armada could be swallowed by your pet dog, & in fact these kind of things could be happening all the time.
Every day our pets could be saving us from alien invasion.