2019年USAAAO决赛第1题
来自astro-init
Jingsong Guo(讨论 | 贡献)2020年3月7日 (六) 17:28的版本
英文题目
1. (7 points) Assuming that the present density of baryonic matter is $$ρb0 = 4.17*10^28 kg/m3$$ , what was the density of baryonic matter at the time of Big Bang nucelosynthesis (when T = 10^10 K)? Assume the present temperature, T0 to be 2.7 K.