Excitotoxin 发表于 2025-3-28 15:03:38
http://reply.papertrans.cn/88/8733/873279/873279_41.pngEngaged 发表于 2025-3-28 20:47:42
Robertson-Walker cosmology,rtion of the universe. Hence any cosmological model reflects our own prejudice. Nevertheless, there are certain assumptions which seem to have a high degree of plausibility. After having built a cosmological model one can compare it with the few data we do have. Although imperfect, this approach seepalliate 发表于 2025-3-29 02:04:34
Spherical symmetry,plicitly known solutions of Einstein’s equations for physically plausible matter fields have a high degree of symmetry. Secondly, a spherically symmetric spacetimes are very good descriptions of non-rotating, isolated stars and therefore of astrophysical interest. (If the star rotates the rotation a浮雕 发表于 2025-3-29 06:29:30
Singularity theorems,at there has been a big bang — or at least that there are regions in spacetime where general relativity breaks down. They are one of the main motivations for attempting to quantise general relativity. While there is a lot of evidence in favour of this interpretation we will see that there are also o