The endless search for extraterrestrial intelligent life for some smoothly and imperceptibly flows into a real obsession. Scientists cannot understand why we still haven't found anyone, despite all our attempts and a theoretical basis, which clearly hints at a completely different outcome. Recently, more and more new hypotheses have appeared to explain our loneliness. For example, according to one of the latter, it may be in ourselves. However, the German astrophysicist Michael Hippke of the Sonneberg Observatory has a different opinion on this matter.
According to the German researcher, one of the most serious difficulties that may face extraterrestrial civilizations on their path of exploration and exploration of outer space is gravity, which can simply block access to space even for technologically advanced aliens.
What about people, you ask? Indeed, in less than 100 recent years, mankind has not only found a way to go beyond the atmosphere of our home planet, but also began an active study of other planets of the solar system. So why couldn't advanced extraterrestrial civilizations do the same?
The problem, according to Hippke, lies in the planets themselves, which these (hypothetical) extraterrestrial civilizations (hypothetically) call their home.
According to the most common opinion among astronomers, the most suitable planets are the so-called super-earths - rocky exoplanets with significantly higher mass indices in comparison with our Earth, as well as a denser atmosphere that is able to protect conditional life forms on the surface or below it. Such planets, according to scientists, can have all the resources necessary for life. However, they have one serious drawback.
“The more massive the planet is, the more expensive it is to launch a space launch from it,” Hippke commented to Space.com.
In his study, Hippke calculated the required level of thrust that would be required for a spacecraft to escape the atmosphere of an average super-earth or even a more massive planet. According to the calculations obtained, the use of conventional rocket fuel in these cases will quickly transfer such launches from the category of expensive to the category of impossible.
For example, launching the classic Apollo launch vehicle (used to fly to the Moon) from the surface of the super-earth would require approximately 400,000 tons of fuel, which, as Hippke writes in his article published in the online library arXiv.org, “is equivalent to mass of the Cheops pyramid, and also, probably, is a real limit for rockets operating on the basis of KRD (chemical rocket engines). Anything bigger will be too expensive."
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Hippke's calculations show that the use of spacecraft based on the HRD using conventional fuel would be possible, but too impractical for civilizations living on the surface of super-earths. However, if we are talking about even more massive worlds, then their inhabitants will have to look for alternative options for power plants, for the possibility of going into space, one of which may be, for example, nuclear power plants.
The larger the planet and its mass, the less the efficiency of chemical fuel becomes. Lack of efficiency = increased consumption. Increased consumption = reduced economic viability. Ultimately, Hippke notes, each launch will require so much fuel that it will generally reduce the number of possible launches and, as a result, the development of the space program.
But since we are talking about hypothetical extraterrestrial civilizations, it is quite possible that we are talking about completely different, completely different from our technologies, allowing them to explore outer space. Nevertheless, we have another quite reasonable explanation of why we still haven't found anyone in space.
Nikolay Khizhnyak
