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Basically, humanity as an intelligent community is considered a unique case in the Universe and the result of an extremely successful coincidence. Recently, scientists have considered this issue from the point of view of the history of the Earth and have come to the conclusion that there is no luck, but a natural process. On another planet, it can happen even faster than on ours. The solar system has existed for 4,6 billion years. If we consider the moment of the emergence of intelligent civilization in this system to be the emergence of writing, then in this sense humanity is only five thousand years old. Even if we take the first use of tools by a human ancestor as the starting point, the age of earthly civilization still turns out, by cosmic standards, to be a meager 2,6 million years.
The Sun is predicted to continue its thermonuclear "life" for another five billion years, but modern science suggests that it will eventually become more intense and in one to two billion years the Earth will be too hot not only for humans, but perhaps for life in general. In this regard, scientists ask themselves: why did we, as an intelligent community, appear "under the curtain" when we already have relatively little time left?
British physicist Brandon Carter in 1983 put forward the hypothesis of "difficult steps": he believed that evolution in general is too slow and most often it must require more time to create intelligent beings than a star can provide. The Earth, in Carter's view, was simply lucky to go through difficult intermediate stages. Among them, the scientist mentioned the appearance of DNA and the separation of human ancestors from primates.
This line of thought resonates with other well-known concepts. First, there is the Drake equation, a formula proposed in 1961 by Frank Drake as an attempt to calculate the expected number of intelligent civilizations in our own Milky Way galaxy. There are so many unknowns in this formula that it has been interpreted in different ways. Proponents of human exceptionalism appeal to the rarity of Earth-like planets and the fact that, again, it is highly unlikely that an evolutionary coincidence would be necessary for intelligent beings to emerge.
It is also worth mentioning the Great Filter theory, which looks even further: it talks about obstacles to an intelligent civilization not only arising, but also developing enough to become noticeable in vast space, that is, to be detected by other civilizations.
In a recent article for the publication Science Advances Researchers from the USA and Germany examined Brandon Carter's version and explained that he was thinking like an astrophysicist, but they propose to consider the issue from the point of view of geology. The authors of the article expressed the opinion that we are so "late" not because evolution itself takes so much time, but because it happened so on Earth due to its specific features. The researchers emphasized that initially the Earth was unsuitable not only for the emergence of intelligent life, but also for any life in general, except for the most primitive, single-celled. Everything changed the Great Oxygen Event, which is also called the Oxygen Catastrophe, because for most of the life that existed at that time, oxygen became destructive. Only those who adapted to use it survived. But evolutionarily, oxygen turned out to be a gift, because it opened up opportunities for greater biological diversity. If this had not happened, we would not exist.
The “culprits” of this epochal event are microscopic blue-green algae, cyanobacteria, because they are the first known producers of oxygen. This revolution occurred, according to estimates, 2,4–2,2 billion years ago. Thus, the Earth lived for many billions of years before the conditions were created on it to eventually receive humans. So, if we count from this moment, it takes two and a little billion years for intelligent life to arise from microscopic life.
Researchers believe that somewhere on another Earth-like "comfortable" planet, no oxygen catastrophe may occur at all, but it may well turn out the other way around: some analogues of cyanobacteria will appear much earlier. Then, by the time when we on Earth still had the kingdom of sponges and jellyfish, creatures on another planet will already be building cities, telescopes and spaceships.
This is reminiscent of the famous “Fermi paradox” - the question of where extraterrestrial civilizations are and why we don’t find them. However, many astronomers say that it is too early to talk about humanity’s loneliness - we still see and “hear” little in space. In any case, the idea of faster evolution on other planets will remain only a hypothesis until we discover at least one such case.
