For decades, scientists around the world have been trying to find an answer to why we can not find traces of alien life, although it should be common - after all, the universe is huge. They established a range of possibilities, starting with the miracle of cell creation and consciousness, and ending with governmental conspiracies.
You probably know what the Fermi paradox is, even if you're not interested in topics that go beyond the globe. The best definition of this paradox is:
The size and age of the universe suggest that there should be many technically advanced extraterrestrial civilizations. However, such a reasoning is contradicted by the lack of observable evidence of their existence. Thus, either initial assumptions are incorrect and technically advanced life is much rarer than it is believed, either the methods of observation are incomplete and humanity has not yet detected them, either the methods are wrong and human civilization is looking for improper traces.
What, in short, can be understood as:
The universe is huge, so it should contain a multitude of alien civilizations. The problem is that we have never experienced them.
This is true. Looking at the number of stars and planets in our galaxy itself, we should have encountered something long ago. After all, people are not idle. We have televisions, telephones, satellites - and all of this generates radio waves that are noticeable far away from the solar system. In addition, we use huge radio telescopes all the time to receive a potential signal from space. But all this seems to be useless.
And what are the likely reasons?
Aliens don't exist
It is hard to believe that life can be something unprecedented on the scale of the entire cosmos. But there is a chance. It's called Rare Earth Hypothesis. Since the Universe is huge, it contains various combinations of galaxies, planetary systems, and planets.
Let's assume then that we've come across the perfect combination. We are in the galactic region not exposed to cosmic rays because we are far from the center of the Milky Way. We are also not at the very edge where radiation from other galaxies would reach us. The planetary system also suited us, because the Sun is neither too big nor too small, and stars similar to ours are rare - at least this is due to the observation of our cosmic environment. Jupiter, with its large mass, collects comets and asteroids flying towards the Earth, thanks to which we are protected from collisions.
And finally our blue planet. It is not too big, so gravity is not a big challenge even for an ordinary flower. It is also not too far or too close to the star, so it avoids destroying the atmosphere and the magnetic field (which not every planet has!). We have a large-sized moon, which affects the movement of water and the formation of tidal basins, which could have been important for the creation of life. Don't forget about the so-called evolutionary kicks, or events that forced bacteria and unicellular creatures to evolve to adapt to new conditions.
Where did these single-cellers come from? Scientists don't know that yet.
In addition, there is the problem that if it was a miracle to create life, an even greater miracle was the emergence of intelligence and consciousness. After all, for billions of species living on Earth, we are the only one who has full awareness, who is able to ask questions and who explore the world around him.
Adding two to two everything becomes scary. Because we can really be alone in all this cosmic chaos.
Aliens lead to the self-destruction of civilization
Go to the first better news page. Or turn on the TV.
Self-destruction is a disturbing, but also very possible scenario for every civilization. Constant wars, killing for some idea, destroying your own planet for tens or even hundreds of years. It all accumulates, and life is delicate and requires constant care. A moment of egoistical behavior is enough for the plants to start dying out. As a consequence, animals also die.
The short life of a man doesn't help, because most people prefer to blame the previous generations, and give responsibility and work to the next. Because why waste time to renew the environment and fight to stop the destruction of our planet, if within a few decades a man dies. Then it will not be a problem for the dying person anymore. Then he will have only greater peace.
It doesn't have to be limited to us. Every civilization can go through similar situations and events.
And then - there is no one to communicate with us.
Aliens are dying out by an external factor
It can be caused by nature itself. Collisions of asteroids, supernovae, catastrophes within the planet (eg. volcanic eruptions). Local disasters often occur on Earth. As people, we don't always deal with them. So what could a newly emerging civilization do?
On the other hand, the external factor may be another civilization, which has such an advanced technological level that it began to destroy new alien civilizations, so that none would threaten it.
Compared to them, we can still be very primitive, that's why they don't even bother us. And the right technology would allow them to hide from our eyes. What would make sense if they wanted to limit the expenses or potential losses, so they would wait for the self-destruction of a given civilization, only at last attacking it.
Aliens are too far away
Even assuming that life is something common, it will not change the fact of the magnitude of the Universe. And then the distances between civilizations can be a heavy obstacle to avoid.
Our visibility is limited to the light and its speed, so if something is far away, then we see an earlier picture of the place. Therefore, being within a dozen thousand light years away from us, strangers see earthly life in a very primitive form. It may discourage them from communicating. After all, we perceive ants, for example, as hard-working, but still primitive animals. That's why we don't see the point in conducting conversations with them. Because they will not answer us.
Even defeating the problem of communication over vast distances by one side will not make sense to establish contact, if the other part doesn't have such technology to give answers in a reasonable time.
In addition, interstellar travel can be extremely unprofitable and expensive. According to our knowledge, the speed close to the speed of light is the highest possible for anything having mass. And the journey of aliens to us could last longer than their lives, counting it even in generations. Such a trip would be very risky and would require stocks for hundreds or even thousands of years.
In this situation, aliens could simply ignore us, looking for neighbors closer to them.
Aliens are dying out too fast
The universe is almost 14 billion years old. Man as an intelligent being - less than 200,000, where the greatest technological progress lasts several hundred years.
It is very little time on the cosmos scale, like the blink of an eye. Therefore, it is possible that civilizations that have the right level of technology to send signals outside the planet exist for some time and then die out. Thanks to this, it is difficult to find a few advanced civilizations at the same time and close to each other. We can be for a moment the only living civilization in the Milky Way, and somewhere far away, on a small planet, there are the remains of an earlier civilization.
Our civilization will also eventually die so that future alien species can study someone's soup spoon, wondering why we used such weirdly formed metal alloys.
There are no aliens yet
One of the most interesting possibilities is the priority of mankind.
If the universe had its actual beginning, then some civilization had to be the first one. So why would not it be humanity? Perhaps we are the precursors of discovering the secrets of the cosmos. And also future guardians of the next intelligent races.
It is a beautiful vision. Not only because humanity is then the biggest and most intelligent race that ever existed, but also because we are the first to experience the charms and sorrows of life. We are unique beings who have a chance to be teachers for the whole universe.
It's a pity that beautiful visions often collide with brutal reality.
Aliens use different technology
People are limited to not very wide range of signal classes and frequencies. Of course, through our technological limitations. As a consequence, we were able to get hundreds of signals and messages, but their format was different from what scientists expected, which is why they were ignored.
At a time when we have something new to observe and scan the space, it may be too late. Aliens can pick up a lack of appeal as a lack of interest on our part. Or they may no longer exist.
Assuming optimistically that we are not so far away from other civilizations and generally use similar technology - we can look for them too shortly, and they could not even notice us. But there is a shade of chance that it is today some strange guy invented the device, thanks to which he will hear us, so we have to wait until he will find a way to send us a message.
Aliens become new technological beings
Technology can be developed in many ways, but there is certainly a limit somewhere. It is possible that the ultimate goal of technology is to connect the mind with the machine so that the creature is not limited by the organic body.
Lack of contact from their side can be explained then by the impossibility of interacting with the outside world or reaching such a state of knowledge that contact with another race loses any meaning. Just as no one talks about the meaning of life and death with a snail. Because it's just a waste of time.
Aliens isolate us from the rest of the world
It sounds bad, but it doesn't have to be that way.
We could have been isolated from other races in order to be able to calmly grow and understand the senselessness of war and suffering.
There is also an option that we are ordinary test objects. They check our reactions and evolution in different environmental conditions, with different levels of stress and many other factors that we might not have a clue about.
Isolation would be most likely to limit technological progress. If we could get along with the neighboring civilization, which is technologically thousands of years ahead of us, then in one generation, all our technology could look completely different. And then we would become a threat to others because we would not have time to learn our own behavior.
Aliens are different
It is possible that we imagine aliens wrong.
Their structure can be based on completely different elements. They may have a different physiology of the body, the whole psychological and cultural aspect, as well as the appearance and manner of being. Because of this, activities that people perform on a daily basis can be disgusting and discouraging for them.
People wear clothes, various accessories, have a specific way of communication (gestures, facial expressions, different tones of voice) - aliens may not understand it. It can be at odds with their ideologies and beliefs.
And by such huge racial differences, they are not interested in us.
Aliens are hiding
This is quite an extensive option.
Aliens may be hiding to study our behavior, lifestyle and culture. They can also just pretend to be people to live among us for some reason - for example, by banishing from their native planet, a trip for entertainment or simply because of cheaper life on Earth.
Maybe hiding is due to the fact that once some civilization tried to make contact with another, but it ended in failure and unpleasant consequences, such as war. Now they are looking for help among us, but first researching our race, so that it doesn't end in a second war.
And the governments of the whole Earth are concealing them so that people won't be afraid.
In this way, we have reached the end of all probable scenarios, why the aliens don't contact us and why we don't find any traces of them.
I hope that in the future we will discover the truth, because this topic is very interesting (at least for me), and regardless of which option is the real one, it will have a huge impact on how we perceive ourselves, the environment and our whole life .
Thank you all for reading! :)