Recently, astronomers have been able to map around 1 billion stars around us. That sounds impressive, but it's less than 1% of the total number of stars in the Milky Way. It is statistically impossible that we are the first intelligent species in the galaxy. There have been advanced civilizations before us, there are currently developing ways of communicating with us and there will be more. The only question is: where is everyone? One thing that cannot be taken away from humanity is that we are very optimistic and hopeful. All this time we live under the starry sky, many people look at them and think that we are definitely not alone in the Universe. And the statistics tell us that it is very likely that this is not actually the case. There are too many worlds and life is too adaptable. In 2017, a group of British scientists discovered that life developed very soon after the planet itself became habitable. We used to think that the development of life was a highly improbable event, but today that way of thinking is becoming obsolete. Say no to plagiarism. Get a tailor-made essay on "Why violent video games should not be banned"? Get an original essay On the other hand, we have been searching for about 70 years for any sign of extraterrestrial life or any attempt at communication from little big guys - headed humanoids or whatever they are. And we still have absolutely nothing to show. How is this possible? This is exactly the question that was asked by the famous Italian physicist Enrico Fermi, the creator of the very first nuclear reactor. Since then, astronomers and all ET enthusiasts around the world have known about the Fermi Paradox. Simply put, as it was originally formulated: if there absolutely must be developed civilizations in the Universe, then where is everyone? The Fermi Paradox has a lot of potential solutions: something like 75 to be precise, but today I'm going to focus on the main ones, which can possibly explain this troubling absence of aliens around us. The first group is made up of two big ideas: The rare earth hypothesis and the great filter idea. They are closely related to each other and both can be heartbreaking for believers who want to meet aliens in person one day, so please prepare yourself. Can you imagine everything that would have to be put in place for an advanced civilization to reach our level – sending radio signals into space, launching huge telescopes and satellites, searching for exoplanets and life there. Starting with the qualities of the Sun, neighboring planets, the Earth itself and the Moon, and ending with our natural curiosity and aching need to go into space. Let's just say we hit a jackpot in every category. These combined requirements are called the Great Filter and our home planet's ability to pass through it and win the biggest lottery in the Universe – that's what the rare earth hypothesis is. So, what filters are there and what conditions are good enough for our possible extraterrestrial friends to evolve and develop their civilization? Their sun must be something like our Sun - not too bright, not too bright, regardless of the planets orbiting it, but not too much. weak, so they won't be just giant, icy spheres. The planet they live on should be in the habitable zone of their star. One thing to note is that we have already found planets around thestars closest to us, which are exactly like that, so at this point all the mentioned requirements of the Great Filter should be quite satisfactory. The real difficulties begin here. For example, there must be something like Jupiter around. Jupiter is enormous not only in its size, but also in its benefit to us. Its mass attracts all space debris, meteors and comets like a giant vacuum cleaner. Without it, Earth would be constantly bombarded with giant space rocks. Another important thing that supports us is our moon. Did you know that the Moon is the largest natural satellite in the world? The solar system compared to the size of the planet on which it rotates? The Moon's size is a little less than a third of Earth's, and without a body like this in its orbit, Earth would be unstable and unable to support life. The size of our planet and its rotation speed make for an optimal day and night cycle. Our planet contains many chemical elements, crucial for the development of life. Especially hydrogen, nitrogen, carbon, oxygen, sulfur and phosphorus. The latter is actually quite rare throughout the galaxy and comes only from supernova explosions, as shown in a recent study from Cardiff University in Wales. And you think that makes up for a Rare Earth? That's not even half of the factors, and we'll be here all day if we try to go through them all. You certainly get the idea: Earth is indeed an extremely rare planet. More importantly, we are only halfway through the Great Filter. Planets like Earth have yet to appear in the Milky Way. Let's imagine that these planets have evolved some sort of life, but they still need to be able to support it long enough for evolution to work. From self-replicating organic molecules like DNA and RNA, to single-celled organisms, to complex life with distinctive organs, to the full range of species capable of adapting to different environments and inhabiting the entire planet, and finally to an intelligent life form capable of using tools, thinking and communicating. It's a long journey that takes at least 4 billion years. All kinds of things can happen during this time! Gamma-ray bursts passing through a particular part of the galaxy, extreme ultraviolet radiation, collisions with other celestial bodies – if all of this misses the planet we're talking about, we have a winner. Eventually, he will have some sort of humanoids himself, who will look at the sky from time to time and think that they are probably not alone in the Universe. This is exactly how evolution works – always searching for biological complications and the most effective tools of adaptation. And the tool that stands out above all others is intelligence. But these intelligent people will still not be the big winners of this universal lottery. They still need to develop the technology to go into space and send signals. Technological development is difficult enough in itself, but it is not as difficult as developing a society that would allow them to live relatively peacefully and reach for the stars. There's no way to calculate how often any of this can happen in the Universe, but let's be clear: the probability doesn't seem very good. So, the idea of ​​the Great Filter can certainly be the solution to the Fermi Paradox, even if it is bitter. Another solution is much more optimistic. Aliens exist, but we just can't communicate with them properly. What we use as a means of communication are mainly.