“2019年USAAAO决赛第1题”的版本间的差异
来自astro-init
Jingsong Guo（讨论 | 贡献） |
Jingsong Guo（讨论 | 贡献） |
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==英文题目== | ==英文题目== | ||
| − | 1. (7 points) Assuming that the present density of baryonic matter is $$ρ_{b0} = 4.17*10^{-28} kg/m^3$$ , what was the density of baryonic matter at the time of Big Bang nucelosynthesis (when $$T | + | 1. (7 points) Assuming that the present density of baryonic matter is $$ρ_{b0} = 4.17*10^{-28} kg/m^3$$ , what was the density of baryonic matter at the time of Big Bang nucelosynthesis (when $$T \sim 10^{10} K$$)? Assume the present temperature, T0 to be 2.7 K. |
2020年3月7日 (六) 17:34的版本
英文题目
1. (7 points) Assuming that the present density of baryonic matter is $$ρ_{b0} = 4.17*10^{-28} kg/m^3$$ , what was the density of baryonic matter at the time of Big Bang nucelosynthesis (when $$T \sim 10^{10} K$$)? Assume the present temperature, T0 to be 2.7 K.
