1 Department of Astronomy, School of Science, The University of Tokyo , Bunkyo-ku, Tokyo, Japan .
2 Research Center for the Early Universe, School of Science, The University of Tokyo , Bunkyo-ku, Tokyo, Japan .
Astrobiology. 2019 Jan;19(1):126-131. doi: 10.1089/ast.2018.1895. Epub 2018 Aug 21.
The observed value Λ of the cosmological constant Λ is extremely smaller than theoretical expectations, and the anthropic argument has been proposed as a solution to this problem because galaxies do not form when Λ ≫ Λ. However, the contemporary galaxy formation theory predicts that stars form even with a high value of Λ/Λ ∼ 50, which makes the anthropic argument less persuasive. Here we calculate the probability distribution of Λ using a model of cosmological galaxy formation, considering extinction of observers caused by radiation from nearby supernovae. The life survival probability decreases in a large Λ universe because of higher stellar density. Using a reasonable rate of lethal supernovae, we find that the mean expectation value of Λ can be close to Λ; hence this effect may be essential to understand the small but nonzero value of Λ. It is predicted that we are located on the edge of habitable regions about stellar density in the Galaxy, which may be tested by future exoplanet studies.
观测到的宇宙常数 Λ 值极小，远低于理论预期，因此提出了人择论证来解决这个问题，因为当 Λ ≫ Λ 时星系不会形成。然而，当代星系形成理论预测，即使 Λ/Λ ∼ 50 值很高，恒星也会形成，这使得人择论证的说服力降低。在这里，我们使用宇宙星系形成模型来计算 Λ 的概率分布，考虑了由于附近超新星辐射而导致的观察者的消光。在大 Λ 宇宙中，由于恒星密度较高，生命的生存概率会降低。使用合理的致死超新星率，我们发现 Λ 的平均值可以接近 Λ；因此，这种效应对于理解宇宙常数的小但非零值可能是至关重要的。据预测，我们位于银河系中恒星密度的可居住区域的边缘，这可能通过未来的系外行星研究来验证。
