Astronomer David Kipping from Columbia University in the United States offered several explanations for the paradox of the “red sky,” according to which the sky for some reason is not visible to the most numerous types of stars in the Universe-red dwarfs. The scientist’s article is published in the journal Proceedings of the National Academy of Sciences.
Kipping used Bayesian statistics, which show that the probability of an event occurring depends on new information about it. The scientist considered the probability of a reasonable observer for a Sun-type star (spectral type F, G, or K) or a red dwarf. Red dwarfs are five times more common than main-sequence stars and live 20 times longer. In addition, numerous rocky Earth-like planets are found around them.
The chance that a reasonable observer will accidentally appear at a star similar to the Sun, and not at a red dwarf, is one in 100. However, this contradicts the Copernican principle (also known as the principle of mediocrity), according to which humanity does not occupy a special position in the universe.
The scientist concluded that red dwarfs may have a lower probability of intelligent life, a shorter available time window for the evolution of complex life, or a lower probability of habitable planets in the vicinity of red dwarfs. In theory, one or even several of the three options can explain the absence of a “red sky,” since the observer can only occur far away from red dwarfs. As Kipping writes in the article, all three options seem possible due to limited knowledge, but future astrobiological studies will help clarify the exact cause of the paradox.