Where in the Universe is life possible?


    One of the main questions not only of astronomy, but also of science in general is the possibility of the existence of inhabited planets other than ours. Of course, with the development of science, scientists have moved away from ideas about intelligent life and hope to find at least traces of primitive organisms, but even here it is not so simple. Let’s use the example of our home planet to estimate the approximate chances of finding a habitable planet.

    Let’s start with a concept that is more familiar to science lovers, namely the habitable zone is an area of space within a certain range of distances to the star. Our planet fits perfectly into this zone, by the way, Mars was in this zone earlier, but now it is close to its outer border.

    First, it is worth starting from the «hot» — «cold» principle, i.e. the temperature must be balanced so that water in a liquid state could exist on it and, secondly, the temperature must be perceived by organisms without complications. The width of the habitable zone also depends on the size and temperature of the star. However, the suitability of the planet for life depends not only on the habitable zone.

    An equally important factor is the star itself, its age and class. Our Sun is ideal because it is a fairly stable star, located relatively far from the center of the galaxy and not in a system with another star.

    As for stability, it is obvious that a star with constant flares and emissions of huge amounts of energy will not have suitable planets. Yes, flares and bursts of energy are also often recorded on our star, but they are not always directed towards the Earth and they are not so powerful as to harm our environment.

    Why should a star be far from the center of the galaxy? The fact is that near the center of the galaxy, as a rule, the concentration of stars and black holes is greater than closer than at the edges, which means that life on planets is not threatened by the influence of other stars and their systems.

    Most of the stars in the galaxy are not alone, but in systems with other stars and revolve around a common center of mass. In order for such systems to have an inhabited planet, an incredible set of conditions must be fulfilled, which also do not guarantee favorable conditions.

    And even if the star is “normal” and the planet is in the habitable zone, all this does not guarantee the emergence of life on the planet.

    For life to appear, the planet must at least have an ozone layer and a magnetic field that would protect the planet from the effects of a star; the chemical composition must be favorable for the synthesis of organic matter and maintaining water in a liquid state. However, with all this, there is no guarantee that a cosmic body like an asteroid will not fall on the planet. The Earth is lucky with this: it has a conventional shield in the form of Jupiter.

    Summing up, it is clear that it is difficult to find a planet that would cover all the conditions described above, even if all the criteria fit, then it is worth considering that the epochs of the existence of life on this planet may not coincide with the existence of our race, because the age of the planets is measured in billions of years. Therefore, the chances of finding even simple single-celled organisms are scanty, let alone intelligent life.

    Author: Vladislav Kigim. Edited by Fedor Karasenko.

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